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Collagen Supplements: What They Are, Types, Sources and Evidence

VITAMINS & SUPPLEMENTS · GUIDE

Collagen for Tendons, Ligaments and Sports Injuries: What Studies Tested

What small trials and reviews tested with collagen peptides or gelatin for tendons, ligaments and ankle or Achilles problems, and why results from healthy people do not show injury healing.

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

Back to Collagen Supplements: What They Are, Types, Sources and Evidence
Quick answer

3. People with a problem.

2 findings · 2 limited or unclearThe colour follows the evidence label on each card.

  1. Achilles tendinopathy

    Symptom score rose more in the first 3 months on collagen; no adverse events reported [6]

    Design: Crossover pilot, 20 patients, with calf-strengthening exerciseStudy amount: Specific collagen peptides vs placebo, 3 months each

  2. Chronic ankle instability

    Self-rated ankle stability improved; the ankle machine measure did not differ; fewer ankle injuries in the 3-month follow-up [7]

    Design: 50 athletes, randomized, placeboStudy amount: 5 g a day for 6 months

Both studies are small. The pilot is a crossover with only 20 patients; the ankle study relies mostly on questionnaires. Authors of the ankle study include a collagen research firm. [7]

What recent reviews conclude

A 2026 systematic review of six human studies on tendon and ligament tears and post-surgery settings found a "cautiously positive signal" as an add-on to rehabilitation, but low certainty, mixed products, and only one tear study with a clearly defined formulation. [8] The 2022 review noted that collagen-derived peptides were most often part of the supplements tested. [1]

Frequently asked questions

Does collagen heal tendons?

Proper evidence not found. Trials measured blood markers, stiffness or questionnaires; one pilot in Achilles tendinopathy combined collagen with exercise. [6]

Does collagen help with Achilles tendinopathy?

One 20-patient crossover pilot reported better symptom scores alongside calf exercise, so the result is limited. [6]

Does vitamin C with collagen matter for tendons?

Some studies used vitamin C-enriched gelatin, so the effect of collagen alone cannot be separated. [2]

Do athletes need collagen to prevent injuries?

Proper evidence not found for prevention in healthy athletes; the ankle trial involved athletes who already had instability. [7]

Should I use it while recovering from surgery?

Ask your surgeon or physiotherapist first, since supplements may pose risks around surgery. [9]

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, mixed, insufficient evidence, preclinical. Studies of collagen and tendons or ligaments are few and small, and they measure different things: blood markers, tendon stiffness on ultrasound, questionnaires, or re-injury counts. A 2022 systematic review said high-quality studies are scarce and that definitive dietary advice "remains elusive." [1] Label: promising but limited. Rehabilitation of an injury is led by a clinician or physiotherapist; a supplement is not a substitute.

Three kinds of evidence, kept apart

1. Blood markers after a single dose (biomarker only). In 8 men, vitamin C-enriched gelatin (5 g or 15 g) raised circulating glycine and proline, and blood from those given 15 g an hour before rope-skipping showed double the collagen-synthesis marker; serum from the volunteers also changed engineered ligaments in a dish. [2] A later crossover in 10 men with 15 g of gelatin, hydrolyzed collagen or a gummy found a roughly 20% rise in the marker for gelatin and hydrolyzed collagen, but variability was large and no result was statistically significant. [3] A marker in blood is not a stronger tendon.

2. Healthy people, tendon structure. In 39 young men, 15 g a day for 15 weeks of lower-body training did not change tendon size or stiffness more than placebo. [4] In 50 young sedentary men, 10 g a day for 16 weeks increased muscle and Achilles tendon stiffness on ultrasound versus placebo, with no change in tendon size. [5] The two results differ, and stiffness is a mechanical measurement, not a sign of injury recovery.

Limits and what we did not find
  • Proper evidence not found that oral collagen heals a torn tendon or ligament, shortens return to sport, or prevents injuries in healthy athletes. We searched PubMed for collagen peptides and tendon, ligament and ankle trials.
  • Products differ (gelatin, hydrolyzed peptides, products with vitamin C). Do not carry one result to another: see collagen peptides vs gelatin.
  • Injectable "peptides" for injuries are a different topic: tendon and ligament injury claims.
Safety and when to ask
A suspected tear, sudden loss of function or a joint that gives way should be assessed by a clinician; do not rely on a supplement. Supplements can interact with medicines and may carry risks before surgery. [9] Allergy to fish, egg or beef sources is covered in collagen allergy. Talk to a clinician or pharmacist, and see medication interactions. For where collagen sits in the body, see collagen in skin, bone, cartilage, tendon and gut; for joint trials, collagen for skin, joints and bone.
References
  1. Hijlkema A et al. The impact of nutrition on tendon health and tendinopathy: a systematic review. J Int Soc Sports Nutr 2022. PubMed abstract. Read 2026-10-22.
  2. Shaw G et al. Vitamin C-enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr 2017. PubMed abstract. Read 2026-10-22.
  3. Lis DM, Baar K. Effects of different vitamin C-enriched collagen derivatives on collagen synthesis. Int J Sport Nutr Exerc Metab 2019. PubMed abstract. Read 2026-10-22.
  4. Balshaw TG et al. Effect of specific bioactive collagen peptides on tendon remodeling during 15 weeks of lower body resistance training. Med Sci Sports Exerc 2023. PubMed abstract. Read 2026-10-22.
  5. Miyamoto N et al. Collagen peptide supplementation enhances muscle-tendon stiffness and explosive strength: a 16-week randomized controlled trial. Med Sci Sports Exerc 2025. PubMed abstract. Read 2026-10-22.
  6. Praet SFE et al. Oral supplementation of specific collagen peptides with calf-strengthening exercises in Achilles tendinopathy patients (pilot). Nutrients 2019. PubMed abstract. Read 2026-10-22.
  7. Dressler P et al. Improvement of functional ankle properties following supplementation with specific collagen peptides in athletes with chronic ankle instability. J Sports Sci Med 2018. PubMed abstract. Read 2026-10-22.
  8. Latini L et al. Clinical evidence for low-molecular-weight collagen peptides in tendon and ligament tears: a systematic review. Front Med 2026. PubMed abstract. Read 2026-10-22.
  9. Using Dietary Supplements Wisely, National Center for Complementary and Integrative Health (US). Read 2026-10-22.
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.