Vitamins & Supplements · Collagen supplement
Collagen Peptides
Hydrolyzed collagen · also called Hydrolyzed collagen, collagen hydrolysate, colágeno hidrolizado
Collagen peptides are collagen from animal tissue broken into small pieces and sold as powders, capsules, drinks and gummies. They are mainly studied for skin, joint pain, bone and muscle. Pooled trials lean positive for osteoarthritis pain but are mixed for skin, where higher-quality trials show no effect. Fish-based products can cause severe reactions in people with fish allergy.
General information, not medical advice. Last substantive update · Not medically reviewed. A named clinician has not signed off on this page. How this page is made
About Collagen Peptides
Collagen peptides are small pieces of collagen taken by mouth. Trials are mixed: moderate for osteoarthritis pain, mixed for skin, thin elsewhere. Fish allergy and product quality are the main cautions.
What collagen peptides are
Collagen is a main protein in skin, bone, tendon and cartilage. Collagen peptides, or hydrolyzed collagen, are collagen from animal tissue that has been broken into small pieces so it mixes easily into drinks and food.
They are sold as powders, capsules, drinks and gummies. Source tissues named in the studies include cow hides and bones, fish skin and scales, and jellyfish.
Food versus pills
Collagen is found in animal skin, bone and connective tissue, and in foods such as bone broth and gelatin. Amounts of collagen in foods were not read from USDA or NIH sources, so none are stated here.
Trials on this page tested supplements, not foods. No trial comparing food collagen with peptide pills was read. Bone broth, gelatin, marine collagen and other types have their own pages.
What the research shows
Osteoarthritis has the strongest result: a 2024 review of 35 trials found small-to-moderate improvements in pain and function, though it pooled several collagen products.
For skin, early reviews favoured collagen, but a 2025 review found no effect in trials not paid for by drug companies or in higher-quality trials. For bone, muscle and tendons the evidence is low or very low, and for hair, nails and gut lining it is too thin to judge.
At a glance
Traditional uses history, not proof
- Bone broth and gelatin foods are traditional sources of collagen
- Sold as a beauty and joint supplement
Studied for research
- Osteoarthritis pain and function, moderate certainty
- Skin hydration and elasticity, mixed evidence
- Bone density, low certainty
- Muscle gain with exercise, low certainty
- Tendons and ligaments, very low certainty
- Hair, nails and gut lining, insufficient evidence
Main compounds
- Collagen peptides
- Hydroxyproline
- Glycine and proline
Common forms
- Powder
- Capsules and tablets
- Drinks and shots
- Gummies
- Cow-derived and fish-derived products
Research links: 2024 review: collagen derivatives for osteoarthritis (35 trials) · 2025 review: collagen and skin ageing by funding source · 2023 review: oral collagen and skin (26 trials) · 2018 trial: collagen peptides and bone density · 2020 case: anaphylaxis from fish collagen gummies · Research Library · Genes & Biomarkers Library
What it is and its history
- Accepted scientific name
- Collagen peptides (hydrolyzed collagen, collagen hydrolysate)
- Common names
- Collagen peptides (English); Hydrolyzed collagen (English); Collagen hydrolysate (English); Bioactive collagen peptides (English); Péptidos de colágeno (Spanish); Colágeno hidrolizado (Spanish)
- Family or group
- Protein ingredient. Collagen is a main structural protein of skin, bone, tendon and cartilage; supplements are collagen broken into small peptides.
- Harvest and processing
- Made by breaking collagen from animal tissue into small pieces (hydrolysis). Source tissues named in the sources: cow hides and bones, fish skin and scales, jellyfish. Details of the process were not read from a source.
- Look-alikes and adulterants
- Name: Gelatin; Note: Cooked, partly broken collagen. Has its own page.; Name: Marine collagen; Note: Peptides from fish skin and scales; fish allergy is a concern. Has its own page.; Name: Bovine collagen; Note: Peptides from cow hides and bones. Has its own page.; Name: Undenatured type II collagen (UC-II); Note: A different, non-hydrolyzed product; has its own page.; Name: Bone broth; Note: A food made by simmering bones; has its own page.
- Sustainability and conservation
- Not assessed.
What is inside, and how it may work
What it contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.
Main compounds
| Compound | Family | Where it is concentrated | Activity studied | Level of evidence |
|---|---|---|---|---|
| Collagen peptides | protein fragments | Not read from a source. | The ingredient tested in the skin, joint, bone and muscle trials. 13 8 20 | Human data |
| Hydroxyproline | amino acid in collagen | Not read from a source. | Found in collagen and gelatin; the body can turn it into oxalate (urine marker). 6 | Human data |
| Glycine, proline, hydroxylysine | amino acids in collagen | Not read from a source. | Blood glycine, proline, hydroxyproline and hydroxylysine rose after gelatin in one small study. 16 | Human data |
Mechanisms, receptors and pathways
| Target or pathway | Gene or receptor | What was found | Level |
|---|---|---|---|
| Digestion into amino acids and peptides | Not specified in the sources read | After gelatin, blood levels of glycine, proline, hydroxyproline and hydroxylysine rose within an hour in 8 men. Whether intact peptides reach skin or joints was not shown. 16 | Human data |
| Collagen-making markers | P1NP (type I collagen propeptide) | P1NP rose after collagen peptides (bone trial) and after gelatin before exercise. This is a marker, not proof of stronger tissue. 8 16 | Human data |
| Fish collagen as an allergen | IgE antibodies | Fish collagen triggered IgE cross-linking on mast cells in a lab test and cross-reacted across 22 fish species. 7 | Human samples |
| Hydroxyproline to oxalate | Not specified | Gelatin raised urine oxalate and glycolate; the authors estimate hydroxyproline contributes to oxalate made in the body. 6 | Human data |
Absorption, metabolism and elimination
- Absorption
- Digested to amino acids and small peptides; blood amino acids peaked about 1 hour after gelatin in one small study.
- Distribution
- Not found.
- Metabolism
- Hydroxyproline can be converted to glycolate and oxalate (controlled study).
- Elimination
- Oxalate leaves in urine (controlled study).
- Bioavailability
- Not compared across products in the sources read.
Isolated compounds versus whole extracts
Collagen peptides are a processed protein ingredient. Whole foods that contain collagen (skin, bone, connective tissue, bone broth, gelatin) bring other nutrients and different amounts. No trial comparing food collagen with peptide pills was read.
Nutritional composition
No USDA or NIH amounts for collagen in foods were read, so none are stated. Product forms (powder, capsules, drinks, gummies) and source animals come from the existing AlternativeMed summary.
1 moderate certainty1 mixed findings2 low certainty1 very low certainty3 not enough evidence
What was looked at
The 8 benefits and uses checked for Collagen Peptides, each with how strong the evidence is. Tap one to open it.
- Skin hydration, elasticity and wrinklesMixed findings
- Osteoarthritis pain and functionModerate certainty
- Bone densityLow certainty
- Muscle mass and strength (with exercise)Low certainty
- Tendons, ligaments and recoveryVery low certainty
- Hair and nailsNot enough evidence
- Gut lining claimsNot enough evidence
- Collagen with vitamin CNot enough evidence
Lab markers tracked in the studies
Skin hydration and elasticityOsteoarthritis pain and function scoresBone mineral densityFat-free mass and leg strengthP1NP (collagen-making marker)Nail growth rate and broken nails
What is Collagen Peptides good for?
The main studied uses and how strong the human evidence is for each. Most trials are short and use branded products, and several pool different kinds of collagen.
Benefits, one by one
Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.
Skin hydration, elasticity and wrinkles
Mixed findingsMany trials of swallowed collagen peptides report better skin hydration and elasticity than placebo. Two earlier pooled reviews were favourable. A 2025 review that split trials by funding and quality found no effect in trials not paid for by drug companies and none in higher-quality trials. So the result is mixed and depends on who ran the trial.
5 studiesProducts and sources vary (cow, fish, pig). Studied amounts are in th…
Studies, doses and limits
What the trials found
A 2021 review of 19 trials (1,125 people, 95% women) and a 2023 review of 26 trials (1,721 people) both favoured collagen for hydration and elasticity. A 2025 review of 23 trials (1,474 people) found the same overall, but not in trials without drug-company funding, nor in high-quality trials; its authors say there is currently no clinical evidence to support use for skin ageing. One 69-woman trial found better elasticity than placebo after 8 weeks. A 2026 umbrella review of 16 reviews was favourable for skin overall.
Results
Mixed. Pooled trials lean positive, but the better-quality and independent trials do not show an effect.
Effect sizes as reported
2021: favoured collagen for hydration, elasticity and wrinkles. 2023: hydration Z = 4.94, elasticity Z = 4.49. 2025: no effect in non-industry or high-quality trials. No plain-unit sizes in the abstracts.
Why this rating
Mixed because reviews that pool all trials look positive while the 2025 funding and quality split shows no effect. Not rated higher because trial quality is uneven and funding seems to matter.
Form and dose studied
Products and sources vary (cow, fish, pig). Studied amounts are in the studies table.
Who was studied
Mostly women aged 20 to 70.
Limits
Many trials are small, short and funded by makers. Skin was measured with instruments and scores, not with long-term outcomes.
Why researchers looked
Collagen is a main protein of the deeper skin layer, and skin changes with age, so researchers tested whether swallowing it helps.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Not established
Not established in people. Collagen is broken down in digestion; whether the peptides reach skin or joints and act there is not shown in the sources read.
A proposed mechanism does not show that the effect happens in people.
No safety signal in these trials, but they were short. See the Safety tab.
Osteoarthritis pain and function
Moderate certaintyA 2024 pooled review of 35 trials (3,165 people) found collagen products gave small-to-moderate improvements in pain and in how well joints work, compared with placebo or control, with no extra side effects. Most trials were in knee osteoarthritis and several types of collagen were pooled, not only peptides. A separate review of type I hydrolyzed collagen also reported less joint pain.
3 studiesSeveral collagen types studied, so the result is not specific to pept…
Studies, doses and limits
What the trials found
The 2024 trial sequential meta-analysis found pain scores improved (SMD -0.35, moderate certainty) and function improved (SMD -0.31, high certainty), with no more withdrawals or side effects than control. A 2025 review of 36 trials of type I hydrolyzed collagen found studies on joints reported less pain and better function. A 2021 review of 15 trials, mostly in athletes, found collagen peptides most helpful for joint function and pain. None measured rebuilt cartilage.
Results
Small-to-moderate improvement in pain and function scores. It is an add-on, not a replacement for medical care.
Effect sizes as reported
Pain SMD -0.35 (95% CI -0.48 to -0.22); function SMD -0.31 (-0.41 to -0.22).
Why this rating
Moderate: the biggest review rated pain moderate and function high certainty, but it pools different collagen products (hydrolyzed, gelatin, undenatured type II) and pain is self-reported. One author of the 2025 review works for a collagen maker.
Form and dose studied
Several collagen types studied, so the result is not specific to peptides.
Who was studied
Adults with osteoarthritis, mainly of the knee; athletes in the 2021 review.
Limits
Short trials, wide differences between them, mixed products, self-reported pain.
Why researchers looked
Cartilage and joint tissue contain collagen, and osteoarthritis pain is common, so many trials have tested collagen products.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Not established
Not established in people. Collagen is broken down in digestion; whether the peptides reach skin or joints and act there is not shown in the sources read.
A proposed mechanism does not show that the effect happens in people.
Collagen did not raise side effects in the 2024 review.
Bone density
Low certaintyOne 12-month trial in 131 postmenopausal women found small gains in bone density scans with collagen peptides compared with placebo. A 2025 pooled review also reported higher density but with very large differences between trials. A 2025 systematic review said limits in bone studies prevent firm conclusions. Fractures were not shown to fall.
3 studiesOne branded peptide product at one amount for 12 months.
Studies, doses and limits
What the trials found
The 2018 trial (102 of 131 women finished) found spine and femoral neck T-scores rose slightly with collagen and the bone-forming marker P1NP went up. The 2025 meta-analysis found higher density (I2 = 80%) and said results were bigger with calcium and vitamin D. It did not show fewer fractures.
Results
Small gains on scans in one trial and a variable pooled result. Not a replacement for osteoporosis care.
Effect sizes as reported
Spine T-score +0.1 vs -0.03; femoral neck +0.09 vs -0.01 (2018 trial).
Why this rating
Low: one main trial, a pooled result with very high variation, and no fracture data.
Form and dose studied
One branded peptide product at one amount for 12 months.
Who was studied
Postmenopausal women with low bone density.
Limits
One trial, with dropouts; changes are small; fractures not measured.
Why researchers looked
Collagen is a main protein inside bone, so researchers asked whether it adds to bone strength in older women.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Preliminary mechanism
Not established. The trial authors suggest more bone-forming activity based on blood markers; this is not proven.
A proposed mechanism does not show that the effect happens in people.
No safety problem reported in the trial abstract.
Muscle mass and strength (with exercise)
Low certaintyIn a 12-week trial of 53 older men with muscle loss, those who took collagen peptides with strength training gained more fat-free mass and leg strength than those who trained with placebo. Everyone improved with training. A review of 15 trials called muscle results mixed and found no clear extra muscle-building compared with better-quality proteins.
3 studies15 g a day of peptides in the trial (studied amount); other trials va…
Studies, doses and limits
What the trials found
In the 2015 trial fat-free mass rose +4.2 kg with collagen versus +2.9 kg with placebo, and leg strength +16.5 versus +7.3 Nm. The 2021 review found collagen synthesis rose but muscle protein building was no better than with other proteins. The 2025 meta-analysis found a muscle performance effect of SMD 0.60 (0.05 to 1.15).
Results
Modest extra gains when added to training, in small trials.
Effect sizes as reported
Fat-free mass +4.2 vs +2.9 kg; leg strength +16.5 vs +7.3 Nm.
Why this rating
Low: small trials, some linked to a collagen maker, and one review shows no edge over other proteins.
Form and dose studied
15 g a day of peptides in the trial (studied amount); other trials varied.
Who was studied
Older men with sarcopenia; athletes in other trials.
Limits
Small, mostly men, product-specific.
Why researchers looked
Collagen is a protein, so researchers asked whether it helps build muscle.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Not established
Not established. Collagen made collagen-making rise in one review but did not raise muscle protein building more than higher-quality proteins.
A proposed mechanism does not show that the effect happens in people.
No safety problem reported.
Tendons, ligaments and recovery
Very low certaintyA 2026 review of only six human studies found a cautiously positive signal for collagen peptides as an add-on to rehabilitation after tendon or ligament tears or surgery, but called the evidence sparse and low certainty. A small 8-man study with vitamin C and gelatin raised a blood marker of collagen making, which is not the same as a stronger tendon.
2 studiesNot comparable across studies.
Studies, doses and limits
What the trials found
The 2026 review included three direct studies in tears or after surgery and three indirect ones; most oral products had other ingredients too. The 2017 crossover study used 8 healthy men and gelatin, not peptides.
Results
Possible small help as an add-on; too little evidence to say.
Effect sizes as reported
No effect sizes in the abstracts.
Why this rating
Very low: six studies, mixed products, low certainty.
Form and dose studied
Not comparable across studies.
Who was studied
People recovering from tendon or ligament injury; healthy young men in the gelatin study.
Limits
Few studies, mixed products, blood marker only in the gelatin study.
Why researchers looked
Tendons are mostly collagen, which makes the idea natural to test.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Preliminary mechanism
Not established. A blood marker of collagen making doubled in 8 men after gelatin before exercise; this does not show tendon repair.
A proposed mechanism does not show that the effect happens in people.
No safety problems reported in the abstracts.
Hair and nails
Not enough evidenceFor nails, one open-label study of 25 people with brittle nails (no placebo group) reported faster nail growth and fewer broken nails. For hair, the one controlled trial tested a tablet that had fish collagen plus amino acids, iron and selenium, added to hair-loss drugs, so collagen cannot be separated out.
2 studiesOne branded peptide for nails; a multi-ingredient tablet for hair.
Studies, doses and limits
What the trials found
Nail study: growth +12%, broken nails -42%, but no placebo. Hair trial of 83 people: global score 1.67 versus 0.66 with drug treatment alone at 12 weeks, in a multi-ingredient product made by the authors' company.
Results
Too little to judge for collagen alone.
Effect sizes as reported
Nail growth +12%; broken nails -42% (open-label).
Why this rating
Insufficient: no placebo-controlled test of collagen alone for hair or nails.
Form and dose studied
One branded peptide for nails; a multi-ingredient tablet for hair.
Who was studied
People with brittle nails or hair loss.
Limits
Open-label, small, multi-ingredient, company-linked.
Why researchers looked
Hair and nails are mostly keratin, not collagen, but supplements are widely sold for them.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Not established
Not established.
A proposed mechanism does not show that the effect happens in people.
Supplement was generally well tolerated in the hair trial.
Gut lining claims
Not enough evidenceThe idea that collagen 'heals the gut' rests mostly on lab and animal work. The one small human trial read (20 volunteers before a hard run) found no difference from placebo in a gut leakiness test or in gut symptoms.
1 studies10 g a day for 7 days in the trial (studied amount).
Studies, doses and limits
What the trials found
In the 2023 crossover trial collagen did not change exercise-induced gut changes, inflammation markers or symptoms.
Results
No benefit shown in the one human trial.
Effect sizes as reported
No difference (all p > 0.05).
Why this rating
Insufficient: one small trial, neutral; two authors work for a collagen maker.
Form and dose studied
10 g a day for 7 days in the trial (studied amount).
Who was studied
Healthy runners.
Limits
Small, one short exercise test.
Why researchers looked
Marketing links collagen's amino acids to the gut wall.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Preliminary mechanism
Lab and animal ideas only; not shown in people.
A proposed mechanism does not show that the effect happens in people.
No harm reported.
Collagen with vitamin C
Not enough evidenceThe body needs vitamin C to build its own collagen. In an 8-man crossover study, vitamin C-enriched gelatin before exercise raised a blood marker of collagen making. Whether adding vitamin C to collagen peptides improves anything people can feel was not shown in the studies read.
2 studiesGelatin at 5 or 15 g, three times a day for three days in the trial.
Studies, doses and limits
What the trials found
Eight healthy men; 15 g gelatin plus vitamin C before rope skipping doubled P1NP. No outcome such as pain or injury was measured.
Results
Blood marker only. No benefit for skin, joints or tendons was shown.
Effect sizes as reported
P1NP about doubled with 15 g gelatin.
Why this rating
Insufficient: eight people, gelatin not peptides, marker not outcome.
Form and dose studied
Gelatin at 5 or 15 g, three times a day for three days in the trial.
Who was studied
Healthy young men.
Limits
Eight men; marker only.
Why researchers looked
Vitamin C is a known part of collagen building, so makers often add it.
Traditional use
Collagen is a protein found in skin, bone, tendon and cartilage. Swallowed collagen is digested into amino acids and small peptides; that is different from showing it rebuilds those tissues.
Proposed mechanism Preliminary mechanism
Established nutrition: vitamin C is needed for collagen formation (stated in the existing site summary, not re-checked here). The trial result is a blood marker only.
A proposed mechanism does not show that the effect happens in people.
None noted.
Connections to the rest of health
How Collagen Peptides connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.
Explore every connection: goals, body systems, organs, symptoms, genes
A. Wellness goals
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Healthy Skin | Mixed findings | Skin hydration, elasticity and wrinkles: Many trials of swallowed collagen peptides report better skin hydration and elasticity than placebo. Two earlier pooled reviews were favourable. A 2025 review that split trials by funding and quality found no effect in trials not paid for by drug companies and none in higher-quality trials. So the result is mixed and depends on who ran the trial. | 21 14 12 13 15 | |
| Anti Aging Support | Mixed findings | Skin hydration, elasticity and wrinkles: Many trials of swallowed collagen peptides report better skin hydration and elasticity than placebo. Two earlier pooled reviews were favourable. A 2025 review that split trials by funding and quality found no effect in trials not paid for by drug companies and none in higher-quality trials. So the result is mixed and depends on who ran the trial. | 21 14 12 13 15 | |
| Joint Support | Moderate certainty | Osteoarthritis pain and function: A 2024 pooled review of 35 trials (3,165 people) found collagen products gave small-to-moderate improvements in pain and in how well joints work, compared with placebo or control, with no extra side effects. Most trials were in knee osteoarthritis and several types of collagen were pooled, not only peptides. A separate review of type I hydrolyzed collagen also reported less joint pain. | 10 1 5 | |
| Mobility Support | Moderate certainty | Osteoarthritis pain and function: A 2024 pooled review of 35 trials (3,165 people) found collagen products gave small-to-moderate improvements in pain and in how well joints work, compared with placebo or control, with no extra side effects. Most trials were in knee osteoarthritis and several types of collagen were pooled, not only peptides. A separate review of type I hydrolyzed collagen also reported less joint pain. | 10 1 5 | |
| Bone Health | Low certainty | Bone density: One 12-month trial in 131 postmenopausal women found small gains in bone density scans with collagen peptides compared with placebo. A 2025 pooled review also reported higher density but with very large differences between trials. A 2025 systematic review said limits in bone studies prevent firm conclusions. Fractures were not shown to fall. | 8 17 1 | |
| Muscle Recovery | Low certainty | Muscle mass and strength (with exercise): In a 12-week trial of 53 older men with muscle loss, those who took collagen peptides with strength training gained more fat-free mass and leg strength than those who trained with placebo. Everyone improved with training. A review of 15 trials called muscle results mixed and found no clear extra muscle-building compared with better-quality proteins. | 20 5 17 | |
| Recovery Optimization | Very low certainty | Tendons, ligaments and recovery: A 2026 review of only six human studies found a cautiously positive signal for collagen peptides as an add-on to rehabilitation after tendon or ligament tears or surgery, but called the evidence sparse and low certainty. A small 8-man study with vitamin C and gelatin raised a blood marker of collagen making, which is not the same as a stronger tendon. Collagen with vitamin C: The body needs vitamin C to build its own collagen. In an 8-man crossover study, vitamin C-enriched gelatin before exercise raised a blood marker of collagen making. Whether adding vitamin C to collagen peptides improves anything people can feel was not shown in the studies read. | 9 16 22 | |
| Hair Support | Not enough evidence | Hair and nails: For nails, one open-label study of 25 people with brittle nails (no placebo group) reported faster nail growth and fewer broken nails. For hair, the one controlled trial tested a tablet that had fish collagen plus amino acids, iron and selenium, added to hair-loss drugs, so collagen cannot be separated out. | 4 11 | |
| Gut Health | Not enough evidence | Gut lining claims: The idea that collagen 'heals the gut' rests mostly on lab and animal work. The one small human trial read (20 volunteers before a hard run) found no difference from placebo in a gut leakiness test or in gut symptoms. | 18 |
B. Body systems
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Skin Hair Beauty | Biological association | Mixed findings | Studied for: Skin hydration, elasticity and wrinkles Studied for: Hair and nails | 21 14 12 13 15 4 11 |
| Integumentary System | Biological association | Mixed findings | Studied for: Skin hydration, elasticity and wrinkles | 21 14 12 13 15 |
| Bones Joints Muscles | Biological association | Moderate certainty | Studied for: Osteoarthritis pain and function Studied for: Bone density | 10 1 5 8 17 20 9 16 22 |
| Musculoskeletal System | Biological association | Moderate certainty | Studied for: Osteoarthritis pain and function | 10 1 5 |
| Digestive System | Biological association | Not enough evidence | Studied for: Gut lining claims | 18 |
E. Health conditions
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Fish allergy | Adverse effect or risk | Case report | Fish collagen can trigger severe allergic reactions in people with fish allergy. Fish collagen can trigger severe reactions in people with fish allergy. Preparation or compound: Marine (fish) collagen |
19 7 |
| Kidney stones | Not enough evidence | Gelatin raised urine oxalate in a controlled study; stone risk was not shown. Preparation or compound: Gelatin |
6 | |
| Knee osteoarthritis | Preliminary | Collagen derivatives gave small-to-moderate improvements in pain and function scores in a 35-trial review. Preparation or compound: Collagen derivatives |
10 |
I. Biomarkers
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Skin hydration and elasticity | Biological association | Mixed findings | Measured in trials: better in industry-linked and lower-quality trials; no effect in the rest. A lab change is not the same as a health benefit. | 14 12 13 |
| Osteoarthritis pain and function scores | Biological association | Moderate certainty | Measured in trials: lower pain, better function. A lab change is not the same as a health benefit. | 10 |
| Bone mineral density | Biological association | Low certainty | Measured in trials: slightly higher. A lab change is not the same as a health benefit. | 8 17 |
| Fat-free mass and leg strength | Biological association | Low certainty | Measured in trials: higher. A lab change is not the same as a health benefit. | 20 |
| P1NP (collagen-making marker) | Biological association | Low certainty | Measured in trials: higher. A lab change is not the same as a health benefit. | 8 16 |
| Nail growth rate and broken nails | Biological association | Very low certainty | Measured in trials: faster growth, fewer broken nails. A lab change is not the same as a health benefit. | 4 |
K. Biological pathways
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Vitamin C | Preliminary mechanism | Human | Needed to build collagen; tested with gelatin in one small study. | 16 |
L. Active compounds
| Connected to | Kind of connection | Evidence status | Context | Studies |
|---|---|---|---|---|
| Collagen peptides | Biological association | Human | The ingredient tested in the skin, joint, bone and muscle trials. | 13 8 20 |
| Hydroxyproline | Biological association | Human | Found in collagen and gelatin; the body can turn it into oxalate (urine marker). | 6 |
| Glycine, proline, hydroxylysine | Biological association | Human | Blood glycine, proline, hydroxyproline and hydroxylysine rose after gelatin in one small study. | 16 |
Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 26, 2026).
Evidence at a glance: what the research found for 8 outcomes
Each outcome below is one thing researchers measured. Certainty is how far the evidence can be trusted, not how well it works. The full studies are on the next tab.
The evidence
The research centre for Collagen Peptides. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.
Evidence by outcome
Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).
How we rate evidence
High certainty
Several well-run trials or reviews agree; further research is unlikely to change the picture much.
Moderate certainty
Good trials point the same way, but some doubt remains.
Low certainty
Small, short or inconsistent trials. The finding could change with better research.
Very low certainty
Very little or very weak human data. Treat as a possibility only.
Mixed findings
Trials or reviews disagree with each other.
Not enough evidence
Not enough human research to say either way.
Evidence against
Good research found no benefit, or found harm.
We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We started from our existing collagen summary, then re-read PubMed abstracts for every review, trial, case report and lab study cited. Only abstracts were read. Official fact-sheet pages from NIH ODS, NCCIH and MedlinePlus could not be read and are marked unverified.
Study library: every study we checked 22
| Study | Design | People | Product, dose, length | Result |
|---|---|---|---|---|
| Brueckheimer 2025 The Effects of Type I Collagen Hydrolysate Supplementation on Bones, Muscles, and Joints: A Systematic Review. Orthop Rev (Pavia) · PMID 39980497 · DOI |
Systematic review |
36 randomised trials of type I hydrolyzed collagen | Type I hydrolyzed collagen Oral Varied Varied · vs Placebo or control |
Joint studies reported less pain and better function. Bone studies had limits that prevent firm conclusions. Muscle results were inconsistent, mostly positive only when combined with exercise. Not stated in the abstract (Not applicable) Methods, limits and fundingOutcomes: Bone, muscle and joint outcomes Limitations: Wide differences between trials; no meta-analysis numbers. Funding and conflicts: One author works for a hydrolyzed-collagen company; the authors say this did not influence the review. Read: abstract |
| Cammilleri 2025 Toxic metals and metalloids in collagen supplements of fish and jellyfish origin: Risk assessment for daily intake. Open Med (Wars) · PMID 40292256 · DOI |
Laboratory analysis n/a |
Marine collagen supplements (fish and jellyfish), various brands | Marine collagen supplements Oral products tested in a lab · vs EU limits |
Arsenic was highest (average 0.59 mg/kg), then lead (0.13 mg/kg). Mercury was found in only 12% of samples. Brands differed a lot. Jellyfish and one mackerel-skin product had none detected. None passed the EU limits and calculated daily intakes were below tolerable levels. Arsenic 0.59 +/- 0.28 mg/kg; lead 0.13 +/- 0.02 mg/kg (Not applicable) Methods, limits and fundingOutcomes: Lead, cadmium, chromium, mercury, arsenic Limitations: A set of brands, not the whole market; bovine products not tested. Funding and conflicts: Editor-in-chief of the journal declares a role; no other conflicts. Read: abstract |
| Chen 2026 Heavy metal and Microplastic exposure from sports protein Supplements: Integrated health risk modeling and scenario analysis. Environ Res · PMID 41655677 · DOI |
Laboratory analysis n/a |
30 30 sports protein products sold in China (one was collagen) |
Sports protein supplements Oral products tested in a lab |
Every sample had at least one metal. One collagen product had mercury at 0.02 mg/kg. Microplastics were found in all samples (2 to 19 particles per 30 g serving). Collagen sample mercury 0.02 mg/kg (Not applicable) Methods, limits and fundingOutcomes: Arsenic, cadmium, lead, mercury; microplastics Limitations: Only one collagen product among 30; results do not apply to collagen as a whole. Funding and conflicts: No competing interests declared. Read: abstract |
| Hexsel 2017 Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails. J Cosmet Dermatol · PMID 28786550 · DOI |
Open label trial |
25 25 people with brittle nails |
Specific bioactive collagen peptides (one branded product) Oral 2.5 g once a day (studied in the trial) 24 weeks, then 4 weeks off |
Nail growth rose 12% and broken nails fell 42%. 64% had global improvement. With no placebo group these results could be due to expectation. Nail growth +12%; broken nails -42% (Not given in the abstract) Methods, limits and fundingOutcomes: Nail growth rate, broken nails, global improvement Limitations: Open-label, no placebo, 25 people, one product. Funding and conflicts: Branded product named in the abstract; funding not stated. Read: abstract |
| Khatri 2021 The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review. Amino Acids · PMID 34491424 · DOI |
Systematic review |
15 randomised trials: 12 in recreational athletes, 2 in older adults, 1 in untrained women | Collagen peptides with exercise Oral Varied; collagen synthesis was higher at 15 g a day Varied · vs Placebo or other protein |
Most helpful for joint function and joint pain. Some gains in body composition, strength and recovery. Collagen making rose at 15 g a day but muscle protein building was not better than with higher-quality proteins. Not stated in the abstract (Not applicable) Methods, limits and fundingOutcomes: Joint pain, body composition, muscle recovery, muscle and collagen making Limitations: Mostly athletes; small trials; mechanisms unclear. Funding and conflicts: A company statement says it had no part in conceiving or writing the review. Read: abstract |
| Knight 2006 Hydroxyproline ingestion and urinary oxalate and glycolate excretion. Kidney Int · PMID 17021603 · DOI |
Controlled human study |
Healthy volunteers on controlled oxalate diets | Gelatin (rich in hydroxyproline) compared with whey protein Oral 30 g of gelatin or whey in the main comparison (studied in the trial) Single controlled diets · vs Whey protein |
Urinary oxalate was 43% higher and glycolate 5.3-fold higher after gelatin than after whey. Changes were seen with 5 and 10 g loads but not 1 or 2 g. Kidney stone rates were not measured. Oxalate +43%; glycolate 5.3-fold (Not given in the abstract) Methods, limits and fundingOutcomes: Urinary oxalate and glycolate Limitations: Gelatin, not collagen peptides; number of volunteers not in the abstract; urine marker, not stones. Funding and conflicts: Public research funding listed (NIH). Read: abstract |
| Kobayashi 2016 Fish collagen is an important panallergen in the Japanese population. Allergy · PMID 26785247 · DOI |
Laboratory human samples human samples |
Blood from Japanese people with fish allergy | Fish collagen (mackerel) as an allergen |
Half (50%) of the people with fish allergy had IgE antibodies to mackerel collagen. The antibodies cross-reacted with 22 fish species (87% to 98%). Collagen also triggered mast cells in a lab test. 50% had IgE to mackerel collagen (Not given in the abstract) Methods, limits and fundingOutcomes: IgE antibodies to fish collagen Limitations: Lab and blood tests, not a swallowing challenge; Japanese raw-fish eaters. Funding and conflicts: No funding detail in the record read. Read: abstract |
| König 2018 Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women-A Randomized Controlled Study. Nutrients · PMID 29337906 · DOI |
Randomised controlled trial |
131 131 postmenopausal women with age-related low bone density (102 finished) |
Specific collagen peptides Oral 5 g a day (studied in the trial) 12 months · vs Placebo |
Bone density T-scores rose slightly with collagen (spine +0.1 vs -0.03; femoral neck +0.09 vs -0.01). The bone-forming marker P1NP rose with collagen. Fractures were not measured. Spine T-score +0.1 vs -0.03 (p = 0.030); femoral neck +0.09 vs -0.01 (p = 0.003) (Not given in the abstract) Methods, limits and fundingOutcomes: Bone mineral density (spine, femoral neck); bone markers P1NP and CTX Limitations: One product; about a fifth dropped out; changes are small; fractures not measured. Funding and conflicts: Authors declare no conflict of interest, but the study uses a branded peptide and several authors have worked with its maker in other papers; check the full text. Read: abstract |
| Latini 2026 Clinical evidence for low-molecular-weight collagen peptides in tendon and ligament tears: a systematic review with narrative synthesis. Front Med (Lausanne) · PMID 42666580 · DOI |
Systematic review |
6 human studies in tendon or ligament tears and after surgery | Hydrolyzed or low-molecular-weight collagen peptides Oral or injected Varied Varied · vs Various |
A cautiously positive signal as an add-on to rehabilitation, but the evidence is sparse, varied and low certainty. Most oral products also contained other ingredients. Not stated (Not applicable) Methods, limits and fundingOutcomes: Pain, function, painkiller use, imaging Limitations: Only 6 studies; mostly multi-ingredient products; only one direct tear study used a clearly defined peptide. Funding and conflicts: Two authors work at physiotherapy clinics; no commercial relationships declared. Read: abstract |
| Liang 2024 Efficacy and safety of collagen derivatives for osteoarthritis: A trial sequential meta-analysis. Osteoarthritis Cartilage · PMID 38218227 · DOI |
Systematic review meta analysis |
3165 35 randomised trials in people with osteoarthritis (25 trials, 2,856 people, in the main analysis) |
Collagen derivatives (hydrolyzed collagen, gelatin, undenatured type II collagen and others) Oral Varied by trial Varied · vs Placebo or control |
Small-to-moderate improvement in pain and in function versus control. Collagen derivatives did not raise the risk of side effects or dropouts. Pain SMD -0.35; function SMD -0.31 (Pain -0.48 to -0.22 (moderate certainty); function -0.41 to -0.22 (high certainty)) Methods, limits and fundingOutcomes: Pain and function scores; withdrawals and side effects Limitations: Groups different collagen products together, so the result is not specific to peptides. Pain is self-reported. Cartilage repair was not measured. Funding and conflicts: No conflict statement in the record read. Read: abstract |
| Milani 2023 Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study. Skin Res Technol · PMID 37357646 · DOI |
Randomised controlled trial |
83 83 people with hair loss (pattern hair loss or long-lasting telogen effluvium) |
One tablet with fish collagen (300 mg) plus taurine, cysteine, methionine, iron and selenium, added to drug treatment Oral tablet 1 tablet a day (studied in the trial) 12 weeks · vs Drug treatment alone |
Hair scores were better in the group with the tablet plus drugs (1.67 vs 0.66 at 12 weeks). Collagen cannot be separated from the other ingredients. Global score 1.67 vs 0.66 (p < 0.001) (Not given in the abstract) Methods, limits and fundingOutcomes: Global assessment of hair loss from photographs Limitations: Multi-ingredient tablet; assessor-blinded only (no placebo); short. Funding and conflicts: Two authors work for the company that sells the supplement. Read: abstract |
| Myung 2025 Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Am J Med · PMID 40324552 · DOI |
Systematic review meta analysis |
1474 23 randomised controlled trials |
Hydrolyzed collagen (collagen peptides) taken by mouth (collagen supplements) Varied Varied by trial Varied · vs Placebo |
Across all 23 trials collagen improved hydration, elasticity and wrinkles. In trials not funded by drug companies there was no effect. High-quality trials showed no significant effect on any measure. The authors say there is currently no clinical evidence to support use to prevent or treat skin ageing. Numbers not given in the abstract (Not given in the abstract) Methods, limits and fundingOutcomes: Skin hydration, elasticity and wrinkles, split by funding source and study quality Limitations: Abstract gives no effect sizes. Search ended June 2024. Funding and conflicts: No conflict statement in the record read. The review itself looked at drug-company funding of trials. Read: abstract |
| Proksch 2014 Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study. Skin Pharmacol Physiol · PMID 23949208 · DOI |
Randomised controlled trial |
69 69 women aged 35 to 55 |
Collagen hydrolysate (one specific collagen peptide product) Oral 2.5 g or 5.0 g once a day (studied in the trial) 8 weeks, plus 4 weeks follow-up · vs Placebo |
Skin elasticity was better than placebo in both collagen groups at 8 weeks, and still higher at 4 weeks after stopping in older women. Moisture and water loss did not reach statistical significance. No side effects were noted. Elasticity improved versus placebo (numbers not in the abstract) (Not given in the abstract) Methods, limits and fundingOutcomes: Skin elasticity (main), moisture, water loss, roughness Limitations: Small trial, 23 per group, short, one product, women only. Funding and conflicts: No funding or conflict statement in the record read; the product is a branded peptide, so manufacturer links are possible. Read: abstract |
| Pu 2023 Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients · PMID 37432180 · DOI |
Systematic review meta analysis |
1721 26 randomised controlled trials |
Hydrolyzed collagen (collagen peptides) taken by mouth Varied (fish, cow, pig and other sources) Varied by trial Varied; hydration effects differed by length of use · vs Placebo |
Skin hydration (Z = 4.94) and elasticity (Z = 4.49) were better than with placebo. Effects on hydration varied with collagen source and length of use. The authors found several biases in the included trials and call for larger trials. Z = 4.94 (hydration); Z = 4.49 (elasticity); both p < 0.00001 (Not given in the abstract) Methods, limits and fundingOutcomes: Skin hydration and elasticity Limitations: Biases in the included trials; effect sizes in plain units were not in the abstract. Funding and conflicts: Authors declare no conflict of interest; funders had no role. Read: abstract |
| Ravindran 2026 Collagen Supplementation for Skin and Musculoskeletal Health: An Umbrella Review of Meta-Analyses on Elasticity, Hydration, and Structural Outcomes. Aesthet Surg J Open Forum · PMID 41809116 · DOI |
Umbrella review |
7983 16 systematic reviews covering 113 randomised trials |
Collagen supplements (various types) Oral Varied Varied · vs Placebo or control |
Skin, musculoskeletal and osteoarthritis outcomes were favourable overall; oral health and heart-metabolic markers gave mixed results. The authors call the benefits consistent and meaningful. Numbers not given in the abstract (Not given in the abstract) Methods, limits and fundingOutcomes: Skin, muscle and bone, osteoarthritis, oral health, heart and metabolic markers Limitations: Pools many collagen types, not only peptides. It sits alongside the 2025 skin review that found no effect in higher-quality trials, so its strong wording is not shared by all reviews. Funding and conflicts: No conflict statement in the record read. Read: abstract |
| Shaw 2017 Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr · PMID 27852613 · DOI |
Randomised crossover trial |
8 8 healthy young men |
Vitamin C-enriched gelatin (not collagen peptides) Oral 5 g or 15 g, three times a day for 3 days (studied in the trial) Single doses, then 3 days · vs Placebo |
Gelatin raised blood glycine, proline and hydroxyproline. After 15 g before exercise, a blood marker of collagen making (P1NP) doubled. Ligaments grown in the lab and treated with the blood serum had more collagen. P1NP about doubled with 15 g gelatin (Not given in the abstract) Methods, limits and fundingOutcomes: Blood amino acids, collagen-making marker (P1NP), engineered ligaments in the lab Limitations: Eight men; blood marker only; gelatin, not peptides; no injury outcome. Funding and conflicts: Public research funding listed (NIH). Gelatin product source not stated in the abstract. Read: abstract |
| Sun 2025 Efficacy of collagen peptide supplementation on bone and muscle health: a meta-analysis. Front Nutr · PMID 41049371 · DOI |
Meta-analysis |
Randomised trials of collagen peptides alone or with calcium and vitamin D | Collagen peptides Oral Varied Varied · vs Placebo or control |
Collagen peptides raised bone density at the femoral neck and spine, but results differed a lot between trials (I2 = 80%). Bone markers (SMD 0.40 to 0.58) and muscle performance (SMD 0.60) improved. Results were larger with calcium and vitamin D. Bone markers SMD 0.40 to 0.58; muscle SMD 0.60 (0.05 to 1.15) (Muscle 0.05 to 1.15) Methods, limits and fundingOutcomes: Bone density, bone turnover markers, muscle performance, fracture risk Limitations: Very large differences between trials for bone density. Fractures themselves were not shown, despite the conclusion's wording. Funding and conflicts: Authors declare no commercial relationships. Read: abstract |
| Taylor 2023 The effects of collagen peptides on exercise-induced gastrointestinal stress: a randomized, controlled trial. Eur J Nutr · PMID 36370176 · DOI |
Randomised crossover trial |
20 20 volunteers (16 men) doing a hard 70-minute run |
Collagen peptides Oral 10 g a day (studied in the trial) 7 days before, and 45 minutes before, the run · vs Placebo |
No difference between collagen and placebo in the gut leakiness test, inflammation markers or gut symptoms. No difference (all p > 0.05) (Not applicable) Methods, limits and fundingOutcomes: Gut leakiness test, gut-injury and inflammation markers, gut symptoms Limitations: Small, athletes only, one exercise test. Funding and conflicts: Supplements were supplied by funders; two authors work for a collagen maker. Read: abstract |
| Ueno 2020 A case of pediatric anaphylaxis caused by gummy tablets containing fish collagen. Asia Pac Allergy · PMID 33178560 · DOI |
Case report |
1 One 9-year-old girl with fish allergy |
Fruit gummies containing fish collagen Oral 2 gummies Single exposure |
She had anaphylaxis after two gummies. A supervised challenge with fish collagen confirmed the cause. One confirmed anaphylaxis (Not applicable) Methods, limits and fundingOutcomes: Allergic reaction Limitations: Single case. Funding and conflicts: Authors report no financial conflicts. Read: abstract |
| Zdzieblik 2015 Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial. Br J Nutr · PMID 26353786 · DOI |
Randomised controlled trial |
53 53 men, average age 72, with sarcopenia (age-related muscle loss) |
Collagen peptides Oral 15 g a day (studied in the trial) 12 weeks, with guided strength training 3 times a week · vs Silica placebo plus the same training |
Everyone improved with training. Gains were larger with collagen: fat-free mass +4.2 kg vs +2.9 kg, leg strength +16.5 vs +7.3 Nm, fat mass -5.4 vs -3.5 kg (all p < 0.05). Fat-free mass +4.2 vs +2.9 kg; leg strength +16.5 vs +7.3 Nm (Not given in the abstract) Methods, limits and fundingOutcomes: Fat-free mass, fat mass, leg strength, balance Limitations: Small, men only, one product, short. Funding and conflicts: Funding not stated in the abstract. Some authors are linked to the peptide maker (named in the author list as the company that supplied it is not stated in the abstract), so treat as possibly industry-linked. Read: abstract |
| de Miranda 2021 Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis. Int J Dermatol · PMID 33742704 · DOI |
Systematic review meta analysis |
1125 19 randomised, double-blind, placebo-controlled trials; ages 20 to 70; 95% women |
Hydrolyzed collagen (collagen peptides) taken by mouth Powder, capsule or drink (forms varied) Varied by trial; the review points to about 90 days of use Trials varied; the review highlights 90 days · vs Placebo |
Pooled results favoured hydrolyzed collagen over placebo for skin hydration, elasticity and wrinkles. The authors concluded it is effective after about 90 days. Numbers not given in the abstract (Not given in the abstract) Methods, limits and fundingOutcomes: Skin wrinkles, hydration, elasticity, firmness Limitations: Abstract does not report trial quality, funding or bias. A later review (2025) found different results in better-quality and non-industry trials. Funding and conflicts: No conflict statement in the record read. Read: abstract |
| s-site-summary Existing AlternativeMed collagen nutrient summary (read 2026-10-26) |
Internal summary n/a |
Methods, limits and fundingRead: summary-only |
What we do not know yet
- No long trial showed that swallowed collagen changes skin structure or joint cartilage.
- No fracture trial was read.
- NIH ODS, NCCIH and MedlinePlus collagen pages could not be read.
- No interaction, pregnancy, breastfeeding or children safety data were found.
- Collagen amounts in foods were not read.
- Contamination of bovine collagen and label accuracy were not researched.
How new research is added
New studies are found by a saved PubMed search and placed in a review queue before the page changes.
Lab markers
What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".
Other 6
Skin hydration and elasticity
Better in industry-linked and lower-quality trials; no effect in the rest in trials
Hydration is how much water the outer skin holds. Elasticity is how well skin springs back after being stretched. Both are read with a skin instrument.
Mixed findingsResults and what it means
Why it was measured
To see whether swallowed collagen changes how skin behaves.
Statistical vs. clinical meaning
The result changes with trial quality and funding.
Safety implication
No safety problem was noted in the one trial that reported it.
| Study | Result | People | Product |
|---|---|---|---|
| 14 | Hydration Z = 4.94 and elasticity Z = 4.49 versus placebo | 26 trials, 1,721 people | Hydrolyzed collagen |
| 12 | No effect in trials without drug-company funding or in high-quality trials | 23 trials, 1,474 people | Collagen supplements |
| 13 | Elasticity better than placebo at 8 weeks | 69 women aged 35 to 55 | Collagen peptides daily for 8 weeks |
Osteoarthritis pain and function scores
Lower pain, better function in trials
Questionnaires where people rate their own joint pain and how well they can move.
Moderate certaintyResults and what it means
Why it was measured
To see whether collagen eases joint pain or improves movement.
Statistical vs. clinical meaning
Small-to-moderate changes in self-rated scores; not a measure of cartilage.
Safety implication
No extra adverse events or withdrawals versus control.
| Study | Result | People | Product |
|---|---|---|---|
| 10 | Pain SMD -0.35 (95% CI -0.48 to -0.22); function SMD -0.31 (-0.41 to -0.22) | 35 trials, 3,165 people with osteoarthritis | Collagen derivatives, several types |
Bone mineral density
Slightly higher in trials
A scan that measures how dense bones are. T-scores compare density with a healthy young adult.
Low certaintyResults and what it means
Why it was measured
To see whether collagen changes bone density in older women.
Statistical vs. clinical meaning
Small changes with very large differences between trials; not fracture data.
Safety implication
No problem reported.
Fat-free mass and leg strength
Higher in trials
Fat-free mass is everything except fat (mostly muscle, bone and water), measured with a body scan. Leg strength is measured with a machine.
Low certaintyResults and what it means
Why it was measured
To see whether collagen adds to the effect of strength training in older men.
Statistical vs. clinical meaning
Modest extra gains in one small trial.
Safety implication
None reported.
| Study | Result | People | Product |
|---|---|---|---|
| 20 | Fat-free mass +4.2 vs +2.9 kg; leg strength +16.5 vs +7.3 Nm (both p < 0.05) | 53 men aged about 72 with sarcopenia | Collagen peptides plus training for 12 weeks |
P1NP (collagen-making marker)
Higher in trials
A blood marker that rises when the body makes type I collagen (bone and connective tissue).
Low certaintyResults and what it means
Why it was measured
Used as a stand-in for collagen building in bone and tendon studies.
Statistical vs. clinical meaning
A blood marker, not a measure of stronger bone or tendon.
Safety implication
None reported.
Nail growth rate and broken nails
Faster growth, fewer broken nails in trials
How fast nails grow and how often they crack or chip.
Very low certaintyResults and what it means
Why it was measured
To see whether collagen helps brittle nails.
Statistical vs. clinical meaning
No placebo group, so the change may be expectation.
Safety implication
None reported.
| Study | Result | People | Product |
|---|---|---|---|
| 4 | Growth +12%; broken nails -42% | 25 people with brittle nails | Collagen peptides daily for 24 weeks, no placebo |
Safety
What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.
Main points to know 3
- Fish-derived collagen can cause severe allergic reactions in people with fish allergy. In a Japanese study half of the people with fish allergy had antibodies to fish collagen, and the antibodies reacted across 22 fish species. A 9-year-old girl with fish allergy had anaphylaxis after two gummies made with fish collagen. Marine collagen products come from fish skin and scales. Ask an allergist before using any marine collagen if you have a fish allergy. Laboratory study and case report 7 19
- Metal contamination varies by brand. A 2025 lab study of marine collagen supplements found arsenic and lead in many samples, with big differences between brands. None passed the EU limits and calculated daily intakes were below tolerable levels. A 2026 study of 30 sports protein products found at least one metal in every sample, including one collagen product with a little mercury. These are small brand-level tests, not a survey of all products, and bovine collagen was not covered. Laboratory analysis 2 3
- Possible link with kidney stones is a question, not a finding. Collagen and gelatin contain hydroxyproline, which the body can turn into oxalate. In a controlled study, 30 g of gelatin raised urine oxalate by 43% compared with whey protein. Whether collagen supplements raise the chance of kidney stones was not shown in the sources read. People who have had kidney stones should ask a doctor. Controlled human study (urine marker) 6
Side effects 4
| Effect | How often | Severity and recovery | Evidence |
|---|---|---|---|
| No extra side effects or dropouts in osteoarthritis trials Rates of mild stomach upset, bloating or taste complaints were not given in the abstracts read. | Not different from control in a 35-trial review | Not applicable Not applicable | Meta-analysis 10 |
| No side effects noted in a skin trial | None noted in 69 women over 8 weeks | Not applicable Not applicable | Randomised trial 13 |
| Allergic reaction (hives, swelling, anaphylaxis) to fish collagen Reaction to cow or pig sources was not covered in the sources read. | One confirmed child case; half of fish-allergic people in one Japanese sample had antibodies | Can be life-threatening Needs emergency treatment | Case report and laboratory study 19 7 |
| Higher urine oxalate (lab marker) | 43% higher after 30 g gelatin than after whey in one study | Not a stone outcome Not studied | Controlled human study 6 |
Liver
No liver injury from collagen peptides was found in the sources read. A liver-safety reference (LiverTox) was not opened.
How often. No frequency was found.
Monitoring. No agency monitoring advice was found.
This is a safety connection. It is not evidence that Collagen Peptides supports liver health.
Medicines and supplements 3
| With | Why it matters | Importance | Evidence | What to do |
|---|---|---|---|---|
| Prescription medicines (general) prescription | No mechanism found. | No interaction study between collagen peptides and any medicine was found in the sources read. | Absence of evidence Not enough evidence | Absence of a study is not proof of safety. Tell a doctor or pharmacist about all supplements. |
| Other supplements, including vitamin C supplement | Vitamin C is often added to collagen products. The sources read did not report a harmful combination. | No interaction reported. | Absence of evidence Not enough evidence 16 | Check labels for added ingredients. Ask a pharmacist. |
| Calcium and vitamin D supplement | Studied together with collagen for bone, and results were reported as larger. | A benefit signal, not a safety issue. | Meta-analysis Low certainty 17 | Ask a doctor before combining bone supplements. |
Who should check first 4
| Situation | Advice | Evidence |
|---|---|---|
| Fish allergy (marine collagen) | Avoid fish-derived collagen unless an allergist says otherwise. Check gummies and processed products for 'fish collagen'. | Case report and laboratory study 19 7 |
| Pregnancy and breastfeeding | No safety study of collagen peptides in pregnancy or breastfeeding was found in the sources read. Ask a doctor or midwife before using it. | Absence of evidence |
| Children | No trial safety data in children were read, apart from the fish-allergy case. Do not give it to a child without a doctor's advice. | Absence of evidence and case report 19 |
| History of kidney stones or kidney disease | Ask a doctor. Gelatin raised urine oxalate in one study; effects of collagen supplements on stones were not studied. | Controlled human study 6 |
Overdose, product quality and regulators
Summary. No poisoning or overdose reports for collagen peptides were found in the sources read.
Animal. Not reviewed.
High dose or long term signals. Long-term safety beyond about 12 months was not found in the trials read.
Overdose response. Not found.
Genotoxicity. Not researched.
Product quality depends on the raw material and the maker. Two small lab studies looked at metals; neither covered bovine collagen, bone broth powders or label accuracy.
Metals in marine collagen. Arsenic highest (average 0.59 mg/kg), lead 0.13 mg/kg; mercury in 12% of samples; jellyfish and one mackerel-skin product had none detected; none passed EU limits. 2
Metals and microplastics in sports proteins. All 30 products had at least one metal and microplastics. One collagen sample had mercury at 0.02 mg/kg. 3
Added ingredients. Collagen is sold in gummies, drinks and multi-ingredient tablets, which may add sugar, vitamins, iron or selenium. A fish-collagen gummy caused anaphylaxis in one child. 19 11
| Body | Action | Date |
|---|---|---|
| European Union (limits for metals in food supplements) (European Union) | A 2025 study reports that none of the marine collagen samples it tested passed EU regulatory limits for metals. The limits themselves were not read. source | 2025 |
When to get medical help
- Swelling of the face, lips or tongue, hives, wheezing or trouble breathing after taking a collagen product (especially fish collagen): call emergency services.
- A child with fish allergy who has any reaction after a gummy or drink: get emergency help.
- Severe pain in the side or back, blood in the urine, or fever after starting a gelatin or collagen product in someone with a stone history: see a doctor.
- Persistent vomiting or stomach pain after a product: stop it and see a doctor.
Stop using the product and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.
General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.
Frequently asked questions
What are collagen peptides?
Collagen peptides, also called hydrolyzed collagen, are collagen from animal tissue broken into small pieces so they dissolve easily. They are sold as powders, capsules, drinks and gummies.
Does collagen make skin look younger?
Does collagen help joint pain?
Does collagen strengthen bones?
Does collagen build muscle?
Is collagen good for hair and nails?
Does collagen heal the gut?
This claim rests mainly on lab and animal work. The one small human trial read found no difference from placebo.
Who should avoid marine collagen?
Are collagen supplements safe?
Can collagen supplements contain heavy metals?
Can collagen raise the risk of kidney stones?
Collagen and gelatin contain hydroxyproline, which the body can turn into oxalate. Gelatin raised urine oxalate in one controlled study. Stones were not measured, so it is a question, not a finding.
Is collagen the same as gelatin or bone broth?
No. Gelatin is cooked, partly broken collagen, and bone broth is a food. Each has its own page on this site.
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Editorial transparency
- Written by
- AlternativeMed editorial team. Research compiled with AI assistance, then checked against the sources listed.
- Medical review
- None. This page has not been reviewed by a physician or pharmacist.
- First published
- 2026-10-26
- Last substantive update
- 2026-10-26
- How we research
- We started from our existing collagen summary, then re-read PubMed abstracts for every review, trial, case report and lab study cited. Only abstracts were read. Official fact-sheet pages from NIH ODS, NCCIH and MedlinePlus could not be read and are marked unverified.
- How we rate evidence
- See "How we rate evidence" in the Evidence tab.
- Independence
- No product is promoted on this page. No affiliate links are shown. Several trials were funded by or linked to collagen makers; this is flagged where the abstracts show it.
Sources 22
Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.
- Brueckheimer PJ, Costa Silva T, Rodrigues L, Zague V, Isaia Filho C. The Effects of Type I Collagen Hydrolysate Supplementation on Bones, Muscles, and Joints: A Systematic Review.. Orthop Rev (Pavia). 2025. PMID 39980497. DOI 10.52965/001c.129086. (abstract)
- Cammilleri G, Tortorici M, Pantano L, Galluzzo FG, Pulvirenti A, Buscemi MD et al.. Toxic metals and metalloids in collagen supplements of fish and jellyfish origin: Risk assessment for daily intake.. Open Med (Wars). 2025. PMID 40292256. DOI 10.1515/med-2025-1141. (abstract)
- Chen M, Dong R, Lai W. Heavy metal and Microplastic exposure from sports protein Supplements: Integrated health risk modeling and scenario analysis.. Environ Res. 2026. PMID 41655677. DOI 10.1016/j.envres.2026.123988. (abstract)
- Hexsel D, Zague V, Schunck M, Siega C, Camozzato FO, Oesser S. Oral supplementation with specific bioactive collagen peptides improves nail growth and reduces symptoms of brittle nails.. J Cosmet Dermatol. 2017. PMID 28786550. DOI 10.1111/jocd.12393. (abstract)
- Khatri M, Naughton RJ, Clifford T, Harper LD, Corr L. The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review.. Amino Acids. 2021. PMID 34491424. DOI 10.1007/s00726-021-03072-x. (abstract)
- Knight J, Jiang J, Assimos DG, Holmes RP. Hydroxyproline ingestion and urinary oxalate and glycolate excretion.. Kidney Int. 2006. PMID 17021603. DOI 10.1038/sj.ki.5001906. (abstract)
- Kobayashi Y, Akiyama H, Huge J, Kubota H, Chikazawa S, Satoh T et al.. Fish collagen is an important panallergen in the Japanese population.. Allergy. 2016. PMID 26785247. DOI 10.1111/all.12836. (abstract)
- König D, Oesser S, Scharla S, Zdzieblik D, Gollhofer A. Specific Collagen Peptides Improve Bone Mineral Density and Bone Markers in Postmenopausal Women-A Randomized Controlled Study.. Nutrients. 2018. PMID 29337906. DOI 10.3390/nu10010097. (abstract)
- Latini L, Porta F, Vitale N, Vreju FA, Filippucci E. Clinical evidence for low-molecular-weight collagen peptides in tendon and ligament tears: a systematic review with narrative synthesis.. Front Med (Lausanne). 2026. PMID 42666580. DOI 10.3389/fmed.2026.1891011. (abstract)
- Liang CW, Cheng HY, Lee YH, Liao CD, Huang SW. Efficacy and safety of collagen derivatives for osteoarthritis: A trial sequential meta-analysis.. Osteoarthritis Cartilage. 2024. PMID 38218227. DOI 10.1016/j.joca.2023.12.010. (abstract)
- Milani M, Colombo F, GFM‐O‐Trial Investigators Group. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study.. Skin Res Technol. 2023. PMID 37357646. DOI 10.1111/srt.13381. (abstract)
- Myung SK, Park Y. Effects of Collagen Supplements on Skin Aging: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.. Am J Med. 2025. PMID 40324552. DOI 10.1016/j.amjmed.2025.04.034. (abstract)
- Proksch E, Segger D, Degwert J, Schunck M, Zague V, Oesser S. Oral supplementation of specific collagen peptides has beneficial effects on human skin physiology: a double-blind, placebo-controlled study.. Skin Pharmacol Physiol. 2014. PMID 23949208. DOI 10.1159/000351376. (abstract)
- Pu SY, Huang YL, Pu CM, Kang YN, Hoang KD, Chen KH et al.. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis.. Nutrients. 2023. PMID 37432180. DOI 10.3390/nu15092080. (abstract)
- Ravindran R, Pizzol D, López-Gil JF, Rahmati M, Boyer L, Fond G et al.. Collagen Supplementation for Skin and Musculoskeletal Health: An Umbrella Review of Meta-Analyses on Elasticity, Hydration, and Structural Outcomes.. Aesthet Surg J Open Forum. 2026. PMID 41809116. DOI 10.1093/asjof/ojag018. (abstract)
- Shaw G, Lee-Barthel A, Ross ML, Wang B, Baar K. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis.. Am J Clin Nutr. 2017. PMID 27852613. DOI 10.3945/ajcn.116.138594. (abstract)
- Sun C, Yang A, Teng F, Xia Y. Efficacy of collagen peptide supplementation on bone and muscle health: a meta-analysis.. Front Nutr. 2025. PMID 41049371. DOI 10.3389/fnut.2025.1646090. (abstract)
- Taylor G, Leonard A, Tang JCY, Dunn R, Fraser WD, Virgilio N et al.. The effects of collagen peptides on exercise-induced gastrointestinal stress: a randomized, controlled trial.. Eur J Nutr. 2023. PMID 36370176. DOI 10.1007/s00394-022-03051-2. (abstract)
- Ueno R, Takaoka Y, Shimojo N, Ohno F, Yamaguchi T, Matsunaga K et al.. A case of pediatric anaphylaxis caused by gummy tablets containing fish collagen.. Asia Pac Allergy. 2020. PMID 33178560. DOI 10.5415/apallergy.2020.10.e35. (abstract)
- Zdzieblik D, Oesser S, Baumstark MW, Gollhofer A, König D. Collagen peptide supplementation in combination with resistance training improves body composition and increases muscle strength in elderly sarcopenic men: a randomised controlled trial.. Br J Nutr. 2015. PMID 26353786. DOI 10.1017/S0007114515002810. (abstract)
- de Miranda RB, Weimer P, Rossi RC. Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis.. Int J Dermatol. 2021. PMID 33742704. DOI 10.1111/ijd.15518. (abstract)
- . Existing AlternativeMed collagen nutrient summary (read 2026-10-26). . . (summary-only)
Where to buy
Check the label first. Whatever you buy, look for these:
- The amount of the active ingredient per serving, not just the front-label claim
- A third-party testing mark (USP, NSF or ConsumerLab)
- Other ingredients and allergens
- Ask a pharmacist about interactions with your medicines
Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.
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