Collagen (Hydrolyzed Peptides)
Collagen is a protein your body makes to support your skin and bones, and it makes less as you age. Studies of collagen supplements for skin show benefits, but the research is disputed: one analysis found the benefit only in industry-funded studies, and a published rebuttal disputes how those studies were classified.
Collagen is a protein your body makes to support the skin and bones; it gives connective tissues structural strength and elasticity. It's made mainly of the amino acids glycine, proline and hydroxyproline. The body's production decreases with aging, sun damage, smoking and alcohol. Hydrolyzed collagen (collagen peptides) is absorbed in the digestive tract.
Research & evidence
Strong support Some support Weak or no supportColours show how well the sources back each point. The reason is next to each one.
Collagen peptide supplementation is associated with improved skin elasticity and hydration in multiple meta-analyses, typically over 8-12 weeks of use. The evidence is disputed, however: a 2025 meta-analysis found the benefit only held in industry-funded and lower-quality studies, though a formal published rebuttal disputes how that funding breakdown was classified, and other independent, non-industry-funded reviews have continued to find positive effects.
Mixed evidenceSome support. Results are mixed
Study details
Pu et al. 2023 (26 RCTs, 1,721 participants; academic/hospital-funded, no industry conflict): significant improvement in hydration (Z=4.94, p<0.00001) and elasticity (Z=4.49, p<0.00001). Myung & Park 2025 (23 RCTs, 1,474 participants): overall pooled effect positive, but "studies not receiving funding from pharmaceutical companies revealed no effect... while those receiving funding from pharmaceutical companies did show significant effects"; study quality showed the same pattern. A published rebuttal (Rajan & Divyalakshmi 2025) says "5 of the 7 studies labeled as 'non-funded' should have been considered industry-sponsored" and alleges data-extraction errors in Myung & Park. A 2026 umbrella review (independently funded, no industry conflicts; 16 systematic reviews, 113 RCTs, 7,983 patients) found "consistent and clinically meaningful benefits," but as a review of reviews it doesn't re-run the funding-split analysis at the center of the dispute.
Source: Pu SY, Huang YL, Pu CM, et al. "Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis." Nutrients. 2023 Apr 26;15(9):2080; Myung SK, Park Y. "Effects of Collagen Supplements on Skin Aging." Am J Med. 2025 Sep;138(9):1264-1277; Rajan R, Divyalakshmi C. "Comments on Effects of Collagen Supplements on Skin Aging." Am J Med. 2025 Nov;138(11):e249. View source
Collagen supplementation (specifically, undenatured type II collagen) may reduce joint pain in people with knee osteoarthritis and in healthy people with activity-related joint discomfort, per a 2025/2026 systematic review — though that review was funded by Haleon. A newer, independently funded RCT found that combining UC-II with hydrolyzed collagen added no extra benefit over placebo.
Moderate evidenceSome support. Results are mixed
Study details
Chang, Zhao & Liu 2026 (17 studies): in knee OA, significant WOMAC pain reduction (-9.24, p=0.004) and physical function improvement (-7.31, p=0.043); stiffness did not reach significance (-6.47, p=0.091). In healthy people with activity-related discomfort: "reduced VAS scores and significantly increased the step number to the first onset of pain" (p<0.05). Funding statement: "This work was supported by China R&D, Haleon." Yuenyongviwat et al. 2025 (68 knee OA patients, 12 weeks, funded by the Medical Council of Thailand) found combining UC-II with hydrolyzed collagen added "no additional benefit compared with that of placebo." Undenatured type II collagen (UC-II) is a different product from the hydrolyzed collagen peptides in the skin claim above.
Source: Chang C, Zhao Y, Liu W. "Efficacy and safety of undenatured collagen type II in modulating knee joint function in healthy and osteoarthritis subjects: a systematic review and meta-analysis." Critical Public Health. 2026;36(1):2588891; Yuenyongviwat V, Anusitviwat C, Tuntarattanapong P, et al. "Efficacy of combined undenatured type II collagen and hydrolysed collagen supplementation in knee osteoarthritis." Sci Rep. 2025. View source
Vitamin C is required for the body's own collagen synthesis.
Strong evidenceStrong support. Stated plainly by NIH or an FDA label
Study details
NIH states: "Vitamin C is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters." The fact sheet doesn't recommend pairing vitamin C with collagen supplements.
Source: NIH Office of Dietary Supplements, Vitamin C — Health Professional Fact Sheet (updated July 31, 2025). View source
Dosage
| Form | Amount |
|---|---|
| Any form | There's no official recommended dose. Collagen supplements come as powders, tablets, capsules and liquids. |
Side effects
Well documented Reported (case reports, anecdotal or one study) None reportedThe circle shows how well documented an effect is, not how serious it is. A rarely reported effect can still be serious, so always read ‘When to stop’.
| Effect | Frequency | When to stop |
|---|---|---|
| No side effects reportedNone reportedNo side effects reported by our sources | None reported | Stop and talk to a doctor if anything unusual happens. |
Safety & interactions
Safety
No side effects have been reported from collagen supplements. MSK says it's generally safe to get collagen from food, and advises talking with your healthcare providers before taking collagen supplements.
Contraindications
MSK lists no contraindications for collagen. If you have a food allergy, check the label to see what the collagen is made from.
Drug interactions
MSK's About Herbs page lists no drug interactions for collagen. MSK notes that supplements can interact with some medications, so talk with your healthcare provider before taking it.