Collagen for Beginners: Skin, Joints and the Evidence

Quick answer

Collagen for beginners, in short: Collagen is the protein that gives skin, joints and tendons their structure, and “collagen peptides” are broken-down collagen you can mix into a drink. Many studies report better skin and less knee-joint pain, but a 2025 review found the skin benefit disappeared in studies not funded by pharmaceutical companies and in the highest-quality studies [3]. Joint and muscle results look more consistent but come with quality caveats [4][5]. We rate the evidence C: encouraging in places, but mixed once study quality is taken into account.

What is collagen?

Collagen is the most common protein in your body. Supplements are usually made from cow, pig, fish or chicken by-products and are “hydrolyzed”, meaning the protein is chopped into small pieces (peptides) that dissolve easily. When you swallow collagen your body digests it like other protein. People take it hoping for firmer skin, comfier joints or help with exercise.

Collagen for beginners: what might it help with?

Possible benefit	Rating	In plain words
Skin hydration, elasticity and wrinkles	Mixed	Positive in most reviews [2], but no effect in independently funded and higher-quality studies [3]
Knee osteoarthritis pain and stiffness	Promising	Small-to-moderate improvements across many trials [4]
Muscle and strength alongside exercise	Promising	Small gains in lean mass and strength, low-to-moderate certainty [5]

Ratings describe how good the research is, not a promise that it will work for you.

What the research says

Does collagen work for skin? Why funding matters

• Skin, positive reviews. A review of 19 trials (1,125 people, mostly women) found hydrolyzed collagen over about 90 days gave better skin hydration, elasticity and fewer wrinkles than placebo [1]. PubMed · DOI
• Skin, a second review. A review of 26 trials (1,721 people) also found better skin hydration and elasticity with oral collagen, though the authors noted risks of bias in the studies [2]. PubMed · DOI
• Skin, the 2025 catch. A newer review of 23 trials (1,474 people) agreed that, combined, collagen improved skin. But when the authors split studies by who paid for them, studies not funded by pharmaceutical companies showed no benefit. High-quality studies also showed no significant effect. The authors concluded there is currently no clinical evidence to support using collagen supplements for skin aging [3]. PubMed · DOI

Funding doesn’t prove a result is wrong, but it is a reason for caution.

Collagen for joints and muscle

• Knee joints. A review of 35 trials (3,165 people with osteoarthritis) found small-to-moderate improvements in pain and function, and no increase in withdrawals or side effects compared with control groups [4]. PubMed · DOI
• Muscle. A review of 19 studies (768 healthy adults) who trained for at least 8 weeks found small gains in fat-free mass and strength with collagen, but the certainty of the evidence was low to moderate [5]. PubMed · DOI

We don’t cover bone or hair here because we haven’t reviewed that evidence.

Amounts and how people take it

These are amounts used in studies, not recommendations.

• Duration: skin trials lasted around 90 days [1]; the muscle review looked at at least 8 weeks of daily use alongside exercise [5].
• Amounts: the reviews we checked pool many products and doses, and none gives a single standard dose we could verify, so we don’t quote one. Follow the serving on the label and check how much collagen peptide it actually contains.
• Form: powders (hydrolyzed collagen or collagen peptides) and capsules are most common. Source (cow, fish and so on) varied between trials.
• Timing: the sources we checked don’t give a firm rule.

Side effects, interactions and who should check first

In the knee review, collagen did not increase side effects or dropouts compared with control groups [4]. Because collagen products come from animals, they matter for some people.

Who should check with a doctor or pharmacist first

Check with a doctor or pharmacist first if you:

• have a fish, shellfish or egg allergy, or avoid beef, pork or other animal products for religious or personal reasons: check the source on the label
• have kidney disease or a medically restricted protein intake, because collagen is protein
• take regular medicines, as we found no reliable interaction data either way
• are pregnant or breastfeeding

Where to buy

Look for the active form and amount (hydrolyzed collagen or collagen peptides, in grams per serving), a stated third-party testing certificate you can check, and work out the price per daily dose rather than comparing pack prices. rather than comparing pack prices. Our collagen buying guide explains how we choose products.

FAQ

What is collagen?

Collagen is the most common protein in your body. Supplements are usually “hydrolyzed” collagen from cow, pig, fish or chicken by-products, meaning the protein is chopped into small pieces (peptides) that dissolve easily in drinks. When you swallow it, your body digests it like other protein.

Does collagen work?

It depends on the goal. Reviews report better skin hydration and elasticity [1][2], but a 2025 review found no skin benefit in studies not funded by pharmaceutical companies or in the highest-quality studies [3]. Knee pain and muscle results look more consistent, with quality caveats [4][5].

How much collagen per day?

The reviews we checked pool many products and doses, and none gives a single standard dose we could verify. Skin trials lasted around 90 days [1], and the muscle review looked at at least 8 weeks of daily use alongside exercise [5]. These are study details, not recommendations, so follow the serving on the label.

Who should not take collagen?

Check with a doctor or pharmacist first if you have a fish, shellfish or egg allergy, avoid certain animal products, have kidney disease or a restricted protein intake, take regular medicines, or are pregnant or breastfeeding. Collagen comes from animals and is protein, so the source and amount matter.

Can you take collagen with blood thinners?

We found no reliable interaction data for collagen with any medicine, including blood thinners, so we can’t say whether the combination is safe or unsafe. Collagen is protein from animal sources. Ask a doctor or pharmacist before combining it with any prescription medicine.

Related pages

• Hyaluronic acid: another supplement people take for skin and joints
• MSM: another supplement people take for joints
• Vitamin C
• Our collagen buying guide
• Longevity supplements for beginners: where this fits in a beginner’s routine
• All supplements A-Z

Talk to your doctor

This page is for general information and is not medical advice. Speak to a doctor or pharmacist before starting any supplement, especially if you are pregnant or breastfeeding, take any medicine, or have a health condition.

References

We cite only studies and official pages we checked against PubMed, the publisher or the agency’s own site. The A to E evidence grades are explained in our editorial policy. See also our medical disclaimer and affiliate disclosure.

1. 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. PubMed · DOI
2. Pu SY, Huang YL, Pu CM, et al. Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients. 2023. PubMed · DOI
3. 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. PubMed · DOI
4. Liang CW, Cheng HY, Lee YH, et al. Efficacy and safety of collagen derivatives for osteoarthritis: A trial sequential meta-analysis. Osteoarthritis Cartilage. 2024. PubMed · DOI
5. Bischof K, Moitzi AM, Stafilidis S, et al. Impact 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-analysis. Sports Med. 2024. PubMed · DOI