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Protein

Collagen

Collagen is the main structural protein in skin, bone, tendons and cartilage. Supplements usually contain hydrolyzed collagen from cattle, pigs or fish.

Also listed as collagen peptides, hydrolyzed collagen, multi collagen, bovine collagen

Hair & SkinBone & JointLongevityFitnessGut Health

Why do skin reviews sound so different?

A 2023 review of 26 trials reported improved hydration and elasticity with hydrolyzed collagen. In a 2025 review of 23 trials, the overall results were also positive, but neither higher-quality studies nor studies without pharmaceutical-company funding showed a statistically significant benefit. That difference makes a confident promise of younger-looking skin hard to justify. 1 2

Skin HydrationMixed

Positive pooled findings become less persuasive when study quality and funding are considered. 2

Anti-aging SkinToo little evidence

The 2025 review did not find convincing support for preventing or treating skin aging. 2

Can collagen help painful knees?

A review published in 2025 pooled 11 trials with 870 people who had knee osteoarthritis. Pain and function improved on average, although results differed substantially between studies. This supports a possible symptom benefit in that population; it does not establish cartilage regrowth or prevention of arthritis. 3

A small change in knee movement

A German trial enrolled 96 otherwise healthy adults with activity-related knee discomfort. After 24 weeks, 40 mg daily of a branded undenatured type II collagen preparation increased knee bending by 3.23 degrees, versus 0.21 degrees with placebo. The manufacturer funded the study. This is a specific movement result, not proof that every collagen powder helps joints. 4

Joint MobilityMixed

The trial found a small improvement in measured knee bending with one preparation. 4

What this page covers

This overview focuses on skin and knee research, rather than hair, gut, bone-density, or exercise-recovery claims.

Effects by health goal

Open an effect to see the studies behind its rating. Bars show the size of the effect; the letter grades the evidence.

Hair & Skin4 effects

Skin HydrationHair & SkinModerateA3 studies
Oral intake of collagen peptide NS improves hydration, elasticity, desquamation, and wrinkling in human skin: a randomized, double-blinded, placebo-controlled study.2023Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta‐analysis2021Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study2018

Rated by SuppCo · high confidenceEvidence record

Skin textureHair & SkinModerateA3 studies
A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density: Results of a Randomized, Placebo-Controlled, Blind Study2019Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study2018Ingestion of bioactive collagen hydrolysates enhance facial skin moisture and elasticity and reduce facial ageing signs in a randomised double-blind placebo-controlled clinical study.2016

Rated by SuppCo · high confidenceEvidence record

Anti-aging SkinHair & SkinModerateA3 studies
Effects of hydrolyzed collagen supplementation for Skin Anti-Aging2025Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis2023Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta‐analysis2021

Rated by SuppCo · high confidenceEvidence record

Hair StrengthHair & SkinSmallB3 studies
Efficacy and Safety of Skin Radiance Collagen on Skin and Hair Matrix: A Placebo-Controlled Clinical Trial in Healthy Human Subjects2024Revitalizing skin, hair, nails, and muscles: Unlocking beauty and wellness with vegan collagen.2024A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen2024

Rated by SuppCo · medium confidenceEvidence record

All studies

25 publications are linked to Collagen, newest first.

Effects of hydrolyzed collagen supplementation for Skin Anti-Aging2025The Impact of Oral Collagen Supplementation on Joint Function, Muscle Recovery, and Musculoskeletal Health in Athletes: A Narrative Review2024Efficacy and Safety of Skin Radiance Collagen on Skin and Hair Matrix: A Placebo-Controlled Clinical Trial in Healthy Human Subjects2024Revitalizing skin, hair, nails, and muscles: Unlocking beauty and wellness with vegan collagen.2024A Clinical Trial Shows Improvement in Skin Collagen, Hydration, Elasticity, Wrinkles, Scalp, and Hair Condition following 12-Week Oral Intake of a Supplement Containing Hydrolysed Collagen2024The Effects of Collagen Peptides as a Dietary Supplement on Muscle Damage Recovery and Fatigue Responses: An Integrative Review2024Impact of Collagen Peptide Supplementation in Combination with Long-Term Physical Training on Strength, Musculotendinous Remodeling, Functional Recovery, and Body Composition in Healthy Adults: A Systematic Review with Meta-analysis2024Oral intake of collagen peptide NS improves hydration, elasticity, desquamation, and wrinkling in human skin: a randomized, double-blinded, placebo-controlled study.2023Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis2023Dietary collagen peptides alleviate exercise-induced muscle soreness in healthy middle-aged males: a randomized double-blinded crossover clinical trial2023UC-II Undenatured Type II Collagen for Knee Joint Flexibility: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Clinical Study2022Collagen Supplements for Aging and Wrinkles: A Paradigm Shift in the Fields of Dermatology and Cosmetics2022Marine Collagen: A Promising Biomaterial for Wound Healing, Skin Anti-Aging, and Bone Regeneration2022Effect of a Daily Collagen Peptide Supplement on Digestive Symptoms in Healthy Women: 2-Phase Mixed Methods Study2022The effects of collagen peptides on exercise-induced gastrointestinal stress: a randomized, controlled trial2022Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta‐analysis2021The Influence of Specific Bioactive Collagen Peptides on Knee Joint Discomfort in Young Physically Active Adults: A Randomized Controlled Trial2021The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review2021A Collagen Supplement Improves Skin Hydration, Elasticity, Roughness, and Density: Results of a Randomized, Placebo-Controlled, Blind Study2019Oral Intake of Low-Molecular-Weight Collagen Peptide Improves Hydration, Elasticity, and Wrinkling in Human Skin: A Randomized, Double-Blind, Placebo-Controlled Study2018

Sources