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VITAMINS & SUPPLEMENTS · GUIDE

Gelatin and Undenatured Type II Collagen

How gelatin and undenatured type II collagen (UC-II) differ from collagen peptides, what trials of 40 mg UC-II show for knee symptoms, and where the evidence stops.

Content last updated . This page has not been medically reviewed.

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Quick answer
Gelatin and UC-II are both called "collagen" but are different products. Gelatin is cooked, partly broken-down collagen used as a food ingredient. UC-II is a small-amount cartilage-derived supplement whose proposed way of working is immune-related, not about supplying amino acids. The trials of UC-II are mostly small, short, and about knee symptoms. The head-to-head of peptides and gelatin is on Collagen peptides vs gelatin, the longer UC-II comparison is on UC-II vs hydrolyzed collagen for joints, and the main guide is Collagen supplements.

Gelatin

Gelatin is made by denaturing and partly breaking down collagen. Hydrolyzed collagen (collagen peptides) is made from the same raw materials, commonly pig or cow skin, and is broken down further. [1] In the same review, commercial gelatin can itself be a starting material for making collagen hydrolysate. [1]

What did people studied show? One small crossover study gave eight healthy men 5 or 15 g of vitamin C-enriched gelatin or placebo before short bouts of rope skipping. After 15 g, a blood marker of new collagen type I (the amino-terminal propeptide) was about double. [2] That is a blood marker in eight men with a vitamin C-enriched product, not a result for skin, joints or bone. In my PubMed searches for randomized trials of gelatin supplements for skin, joints or bone, I did not find a trial of plain food gelatin I could verify, so for those uses: Proper evidence not found for gelatin itself. The trials summarized on the collagen for skin, joints and bone page tested hydrolyzed collagen, not gelatin.

Bone broth is a separate food; see Bone broth vs collagen supplements.

Undenatured type II collagen (UC-II)

UC-II is derived from chicken sternum cartilage. [3] It is processed to keep its structure. A review describes its proposed action as an immune-mediated process called oral tolerance. [4] That is the review's explanation; the human trials below measured symptoms, not that mechanism.
5 findings · 5 supportedThe colour follows the evidence label on each card.

  1. 191 people with knee osteoarthritis, 180 days, 40 mg UC-II vs placebo vs glucosamine plus chondroitin

    Promising but limited

    UC-II improved overall WOMAC symptom score compared with both comparators; safety outcomes did not differ. [3]

  2. 55 healthy people with knee pain after a stepmill test, 120 days, 40 mg UC-II vs placebo

    Promising but limited

    Improved knee joint extension; well tolerated. [5]

  3. Review of 8 randomized trials, 243 people on UC-II

    Promising but limited

    Authors called UC-II promising in early knee osteoarthritis, with limited literature and a need for larger studies. [6]

  4. Review of 12 studies

    Promising but limited

    Authors concluded 40 mg daily was safe and effective in the short and mid-term. [4]

  5. Overview of osteoarthritis supplements

    Promising but limited

    UC-II was one of two supplements with a clinically important effect on pain at medium term; evidence quality across all supplements ranged from very low to high. [7]

Limits: several UC-II trials are small, they were short, and the abstracts I read do not say who funded each one. Results apply to adults with knee osteoarthritis or knee pain, not to skin, bone or other uses, for which Proper evidence not found in the sources read here.

Study amounts

The studies above used 40 mg of UC-II a day. [3] That is a study amount, not a recommendation. It is a tiny amount compared with the grams of collagen peptides used in other trials, and the two products cannot be compared by weight.

Related

Collagen types and sources · Reading supplement labels

Frequently asked questions

Is gelatin the same as collagen?

Gelatin is collagen that has been denatured and partly broken down; hydrolyzed collagen is made from the same raw materials and broken down further. [1]

What is UC-II and how much do studies use?

Undenatured type II collagen from chicken sternum cartilage; the trials above used 40 mg a day. [3] That is a study amount.

Does UC-II work for knee osteoarthritis?

Small to mid-sized trials suggest less pain and better function in the short term, with larger and longer studies still needed. [6]

Is gelatin proven for skin, joints or bone?

Proper evidence not found in the searches described above; one small blood-marker study exists. [2]

Can gelatin or UC-II cause allergic reactions?

They can in people allergic to the source animal, and gelatin can matter in alpha-gal syndrome. [8] Ask an allergy clinician.

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

How to read the evidence labels

Labels used on this page: "promising but limited" (small or short studies, larger ones needed), "insufficient evidence", and "Proper evidence not found" (I looked and found nothing usable).

Safety and who should ask first
  • Allergy: UC-II comes from chicken; gelatin comes from animal skin or bone. Some people with alpha-gal syndrome (a tick-linked allergy to mammal meat) react to gelatin. [8] [9] If you have swelling of the face or throat or trouble breathing after a product, call 911 or your local emergency number. [10]
  • Immune conditions: because UC-II is proposed to act on the immune system, people with autoimmune conditions or on immune-suppressing medicines should ask a clinician or pharmacist first. The sources read here did not study those groups, so the evidence is not found for them.
  • Pregnancy, breastfeeding and children: Proper evidence not found in the sources read here. Ask a clinician.
  • Medicines and quality: see Medication interactions and Quality testing and certifications. Never stop or change a prescribed medicine because of a supplement.
References
  1. Al Hajj W, Salla M, Krayem M, et al. Hydrolyzed collagen: Exploring its applications in the food and beverage industries and assessing its impact on human health - A comprehensive review. Heliyon 2024 (open-access full text read).
  2. Shaw G, Lee-Barthel A, Ross ML, et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr 2017. Read 2026-10-23.
  3. Lugo JP, Saiyed ZM, Lane NE. Efficacy and tolerability of an undenatured type II collagen supplement in modulating knee osteoarthritis symptoms: a multicenter randomized, double-blind, placebo-controlled study. Nutr J 2016. Read 2026-10-23.
  4. Gupta A, Maffulli N. Undenatured type II collagen for knee osteoarthritis. Ann Med 2025. Read 2026-10-23.
  5. Lugo JP, Saiyed ZM, Lau FC, et al. Undenatured type II collagen (UC-II) for joint support: a randomized, double-blind, placebo-controlled study in healthy volunteers. J Int Soc Sports Nutr 2013. Read 2026-10-23.
  6. Kumar P, Bansal P, Rajnish RK, et al. Efficacy of undenatured collagen in knee osteoarthritis: review of the literature with limited meta-analysis. Am J Transl Res 2023. Read 2026-10-23.
  7. Liu X, Machado GC, Eyles JP, Ravi V, Hunter DJ. Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis. Br J Sports Med 2018. Read 2026-10-23.
  8. Tick bites, IgE to galactose-alpha-1,3-galactose and urticarial or anaphylactic reactions to mammalian meat: the alpha-gal syndrome. Allergy 2024. Read 2026-10-23.
  9. Platts-Mills TAE, Li RC, Keshavarz B, et al. Diagnosis and Management of Patients with the alpha-Gal Syndrome. J Allergy Clin Immunol Pract 2020. Read 2026-10-23.
  10. MedlinePlus (US National Library of Medicine). Anaphylaxis. Read 2026-10-23.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.