Collagen for Men: Thirteen Male-Only Trials, Five Head-to-Heads With Milk Protein, and Five Industry Ties in the Record

Collagen is marketed to women for skin and to men, increasingly, for muscle and joints. About 2,200 US searches a month ask about collagen for men specifically. The honest answer starts with a count: how many trials enrolled only men, what they measured, and what the comparison group got. That last column turns out to decide most of what the trials can say.

This page indexes the randomised trials that enrolled men only, found through PubMed on 2026-10-04 and in this site's existing collagen pages. The endpoint-by-endpoint overview for everyone, women included, is on collagen peptides benefits.

The male-only trials

The PubMed search (randomised trials, collagen peptides or hydrolysate, men or male in the title) returned 13 records: ten male-only collagen trials, the Oertzen-Hagemann companion paper, a glucose trial that enrolled men and women, and a blood-flow restriction trial of a different protein. Three male trials whose titles do not say "men" were added from this site's collagen pages: the tendon trial, the gelatin study and the Massey University dairy comparison. A title search can miss others.

Read the comparison column first

Against placebo, collagen with training usually came out ahead on fat-free mass. Four trials report it: elderly men, middle-aged men, young men and trained men. The sizes run from about 1.3 to 1.6 kg more than placebo over 12 weeks in the DXA trials.

Against milk protein, it did not. Five trials put them side by side:

• Brook 2021, 8 older men: 20 g of protein as a collagen-and-milk blend raised muscle protein synthesis as much as 20 g of milk protein, though the blend delivered less leucine. Equal, not ahead.
• Zdzieblik 2021, 97 middle-aged men: collagen +3.42 kg, whey +2.27 kg, placebo +1.83 kg fat-free mass. The collagen-versus-whey difference was not significant (an exploratory analysis).
• Robberechts 2024, 22 fit men: replacing 20 g of a 45 g whey dose with collagen changed nothing in muscle damage or recovery.
• Barclay 2024, 33 men: 25 g of collagen hydrolysate, 25 g of dairy protein and placebo after downhill running. No group differed on any measure.
• Seyhan 2026, 40 trained men: muscle mass +1.59 kg on 30 g whey against +0.46 kg on 10 g collagen. The largest gain, +2.66 kg, was with both. The doses differ threefold, so this is not a gram-for-gram test.

Across both sexes, a 2026 network meta-analysis of 78 trials ranked collagen above whey for strength gains against placebo, with a confidence interval about three times wider; why that ranking and these head-to-heads disagree is taken apart on collagen vs whey protein. Part of the reason is in the amino acids. Collagen lacks tryptophan, which is why its protein-quality score is zero; the composition table is on the same page. A placebo-controlled collagen trial answers "collagen or nothing". For most men choosing a supplement, the live question is "collagen or the protein I would otherwise use".

Fat-free mass is not the same as muscle fibre

Kirmse 2019 took muscle biopsies. Fat-free mass rose more on collagen than placebo, but the cross-sectional area of type II muscle fibres grew in both groups with no difference between them. The authors' own explanation is "enhanced passive connective tissue adaptations", not more muscle fibre. Fat-free mass counts everything that is not fat: water, connective tissue, bone, organs. The tendon trial points the same way, with a larger rise in tendon area on collagen and no difference in strength. How a scale or DXA number differs from measured muscle growth is on creatine for muscle growth, which runs into the same problem.

Joints, tendons, sleep and soreness

• Tendon: Jerger 2022 is the only male trial with a tendon endpoint: Achilles area +11.0% against +4.7%, at 5 g a day. Stiffness, which is what loads a tendon, did not differ. The mixed-sex joint-pain trials (Clark 2008, Zdzieblik 2017) are on the benefits index and on peptides for joints and tendons.
• Running: Jerger 2023 found a longer 1-hour run on collagen in 32 men, with no difference in body composition.
• Soreness: Kuwaba 2023 found lower soreness after a squat session, in a trial whose five company authors work for a gelatin and collagen maker.
• Sleep: Thomas 2024 found fewer polysomnography awakenings over 7 nights in 13 men with sleep complaints, and no difference in sleep quantity, latency or efficiency. The supplement maker supplied the product and employs two authors. The trial's title calls the supplement "glycine-rich"; what collagen's amino-acid profile does and does not supply is on collagen peptides for muscle growth.

Testosterone, hair and skin

Testosterone. None of the 13 abstracts reports testosterone as an outcome. The sleep trial measured endocrine function and found no difference from placebo. Claims that collagen supports male hormones have no male collagen trial behind them in this search. What does and does not move testosterone is on peptides for men and creatine and testosterone.

Skin and hair. The skin trials this site indexes enrolled women (Proksch 2014: 69 women aged 35–55). No male-only skin trial appeared in this search. Peptide Glow Journal covers the skin evidence on collagen peptides for hair and skin.

Who supplied or paid

Five of the 13 trials record an industry tie: the 2015, 2021 and 2022 Freiburg trials through a co-author at a collagen research institute (one with lectures part-supported by a collagen maker and collagen-peptide patents, and a 2025 erratum to the 2015 paper on supply and funding); the soreness trial, whose company authors work for a gelatin and collagen maker; and the sleep trial, supplied by a collagen maker that employs two authors. A sixth, Kirmse 2019, names no funder in its abstract but states that its funders "were allowed to make suggestions in phrasing". The trials with no stated industry tie that compared collagen with whey or dairy protein found no advantage for collagen. A sponsored trial can be accurate. A reader is entitled to the column.

What is not established

• Collagen against an equal dose of whey in men, gram for gram, with biopsies.
• Any male trial of joint pain, skin or hair. The joint and skin trials enrolled mixed or female groups.
• Testosterone or other hormones as a planned outcome.
• Durations beyond 14 weeks for any male endpoint.

How much collagen the trials gave, across all populations, is on how much collagen per day, and what they recorded as side effects is on collagen side effects.

Sources and dates

All abstracts and disclosure statements read via PubMed E-utilities, 2026-10-04.

• Search: ("collagen peptides"[tiab] OR "collagen hydrolysate"[tiab]) AND (men[ti] OR male[ti] OR males[ti]) AND (randomized controlled trial[pt] OR randomised[tiab] OR randomized[tiab]): 13 records.
• Zdzieblik D et al. Br J Nutr 2015;114:1237–45, PMID 26353786 (erratum 2025).
• Kirmse M et al. Nutrients 2019;11:1154, PMID 31126103; Oertzen-Hagemann V et al. Nutrients 2019;11:1072, PMID 31091754.
• Zdzieblik D et al. Int J Environ Res Public Health 2021;18:4837, PMID 33946565.
• Jerger S et al. Scand J Med Sci Sports 2022;32:1131–41, PMID 35403756; Jerger S et al. Sports Med Open 2023;9:103, PMID 37935999.
• Seyhan S et al. BMC Sports Sci Med Rehabil 2026, PMID 42426859 (NCT07171411, registered 2025-09-06).
• Robberechts R et al. Int J Sport Nutr Exerc Metab 2024;34:69–78, PMID 37922892.
• Prowting JL et al. Int J Sport Nutr Exerc Metab 2021;31:32–9, PMID 33186897.
• Kuwaba K et al. J Int Soc Sports Nutr 2023;20:2206392, PMID 37133292.
• Thomas C et al. Eur J Nutr 2024;63:323–35, PMID 37874350.
• Brook MS et al. Clin Nutr 2021;40:4456–64, PMID 33487503.
• Barclay R et al. Nutrients 2024;16:4389, PMID 39771010.
• Shaw G et al. Am J Clin Nutr 2017;105:136–43, PMID 27852613.

Figures are reported as the sources state them. Nothing here is a recommendation or an instruction.