Collagen Science Update – September 2026
Effect of Collagen Peptide Supplementation on Cartilage Degradation Biomarkers in Knee Osteoarthritis: A Randomized Controlled Trial
Most studies on collagen and joint health focus on pain scores and questionnaires. In this study, the researchers went further by examining changes in the cartilage itself. Eighty adults with radiographically confirmed knee osteoarthritis (Kellgren–Lawrence grades II to III) joined a 24-week randomized, double-blind, placebo-controlled trial, with 73 completing the program. Participants took either 10 grams of collagen peptides or a placebo daily. The team measured symptoms using WOMAC and VAS pain scores, and also tracked CTX-II, a biomarker released when type II collagen in cartilage breaks down, along with COMP, another cartilage marker.
After 24 weeks, the collagen group had an 85.2 ng/mmol drop in CTX-II levels, which was over four times greater than the 18.7 ng/mmol reduction in the placebo group (p < 0.001, large effect size). Pain and function improved similarly: VAS pain scores dropped by 2.7 points in the collagen group versus 1.2 in the placebo group, and WOMAC scores improved by 18.4 points compared to 7.9. COMP showed a smaller decrease. No serious adverse events were reported in either group. Because CTX-II reflects cartilage breakdown rather than just symptoms, seeing this biomarker improve alongside symptoms is more convincing than pain scores alone. However, as with any single study, these results should be confirmed by further research.
Key Takeaways:
- In a randomised controlled trial lasting 24 weeks, 73 adults with knee osteoarthritis (KL grade II to III) and who took 10 grams of collagen peptides each day experienced a reduction in CTX-II (marker of cartilage breakdown) that was more than four times greater than that seen with the placebo.
- Improvement in pain and in function matched the changes in the biomarker: the WOMAC scores improved by 18.4 points as compared to 7.9 with placebo, and the VAS pain scores decreased by 2.7 points compared to 1.2.
- It is one of the very small number of studies that have combined patient-reported outcomes with a direct biomarker of cartilage degradation.
Access the study: https://doi.org/10.61919/76wqjg19
Mansoor, M., Shahzadi, N., Safdar, B., Khan, M. A., Saeed, A. F., & Ali, M. (2026). Effect of collagen peptide supplementation on cartilage degradation biomarkers in knee osteoarthritis: a randomized controlled trial. Journal of Health, Wellness and Community Research, 4(7), 1–9. https://doi.org/10.61919/76wqjg19
Efficacy and Safety of Hydrolyzed Collagen Supplementation on Skin Health Outcomes: A Systematic Literature Review of Randomized Controlled Trials
The frequent repetition of the claims made about oral collagen means that it’s easy to forget just how much actual clinical evidence supports them. This systematic review gathered all the evidence from human trials in one place, looking through Embase, MEDLINE, and MEDLINE In-Process for randomized controlled trials that compared oral hydrolyzed collagen with a placebo or an active comparator. It included 25 such RCTs, each involving between 13 and 236 participants, most of them healthy adults, with seven of the trials focusing on people who had osteoarthritis or rheumatoid arthritis and also monitoring outcomes related to the skin and quality of life.
For the outcomes measured most often, hydrolyzed collagen increased skin hydration in 10 out of 15 trials, improved elasticity in 10 out of 13, and reduced wrinkle depth or volume in 9 out of 10. These results were fairly consistent across independent studies. However, improvements in transepidermal water loss, a measure of skin barrier function, were less consistent. Collagen was generally well tolerated, with few adverse events. The authors note that most of the 25 trials had a high risk of bias and recommend larger, standardized, and longer studies to confirm these effects. It should be noted the review received no external funding.
Key Takeaways:
- The systematic review included 25 randomized controlled trials involving oral hydrolysed collagen (with each trial having between 13 and 236 participants) and showed consistent improvements in skin hydration (in 10 out of 15 trials), elasticity (in 10 out of 13 trials), and wrinkle depth or volume (in 9 out of 10 trials).
- Transepidermal water loss (as a measure of skin barrier function) demonstrated an inconsistent improvement, and collagen was well tolerated with only a few adverse events in the combined trials.
- The authors point out that the majority of the trials included had a high risk of bias and recommend that larger, standardized, independently funded randomized controlled trials should be carried out.
Access the study: https://doi.org/10.1038/s41430-026-01778-3
Bassila, C., Bassila, J.-C., & Slim, M. (2026). Efficacy and safety of hydrolyzed collagen supplementation on skin health outcomes: a systematic literature review of randomized controlled trials. European Journal of Clinical Nutrition. https://doi.org/10.1038/s41430-026-01778-3
Effects of Collagen Peptide Supplementation on Bone Turnover, Cytokine, and Inflammatory Markers in Female Distance Runners: A Randomized Pilot Study
Premenopausal female endurance athletes have a specific risk concerning their bone health: when heavy mechanical loading occurs together with low energy availability and chronic inflammatory stress, it can cause the process of bone remodeling to shift towards breakdown. This pilot study is one of the first to investigate whether taking collagen peptide supplements for a short period of time can change that balance. Twenty-two premenopausal women who ran at least 35 miles each week were randomly assigned to receive either 20 grams per day of collagen peptides or an isocaloric maltodextrin placebo, the supplement being taken within an hour of waking. Blood samples were taken both before and after the study to monitor the markers of bone formation and resorption, the osteoclast-signaling proteins, and a major inflammatory cytokine.
In the collagen group P1NP, a marker of new bone formation, increased significantly (from 441 to 464 ng/mL) whereas it did not change in the placebo group. sRANKL, a signal which promotes bone breakdown, decreased in the collagen group and increased in the placebo group, thus moving in a direction that is favorable to bone preservation (p=0.02 between groups). IL-6, an inflammatory marker associated with bone loss and overtraining, decreased significantly in the collagen group while no change was observed in the placebo group (p=0.01 between groups). There was no significant difference between the groups for the bone resorption marker CTX-1. The authors state that this is the first short-term trial to have examined the effect of collagen on bone turnover in young, endurance-trained women and make it clear that due to the small sample size, the short duration of the study and the absence of imaging-based bone outcomes, the results need to be confirmed in larger trials before they can be used in clinical practice.
Key Takeaways:
- In a randomised controlled trial lasting 28 days, female long-distance runners (with a weekly distance of at least 35 miles) who took 20 grams per day of collagen peptides exhibited a significant increase in P1NP, a marker of new bone formation (p=0.04), whereas those who took the placebo showed no change.
- The collagen group also exhibited favourable changes in sRANKL, a factor that promotes bone breakdown, and a significant reduction in the inflammatory marker IL-6 as compared to the placebo.
- This is one of the first short-term trials to look at collagen peptide supplementation and bone turnover in young, endurance-trained women, a group at higher risk for bone health issues. The authors recommend larger studies with imaging-based bone outcomes to confirm these results.
Access the study: https://doi.org/10.3389/fnut.2026.1825906
Kuhlman, N. M., Jagim, A. R., Blesso, C. N., Puglisi, M. J., Chun, O. K., Jones, M. T., & Fields, J. B. (2026). Effects of collagen peptide supplementation on bone turnover, cytokine, and inflammatory markers in female distance runners: a randomized pilot study. Frontiers in Nutrition, 13, 1825906. https://doi.org/10.3389/fnut.2026.1825906
Rehabilitation Nutrition for Tendon and Ligament Injuries: From Collagen Remodeling to Return-to-Activity and Sport
Tendon and ligament injuries take a long time to heal since these tissues have a poor blood supply and collagen is replaced slowly, which is one of the reasons why the rehabilitation periods last for months. This review, which is based on a narrative approach, aimed to summarize the actual evidence from nutrition science during that period of recovery, using clinical, mechanistic, and applied sports-nutrition literature that is relevant to the repair of connective tissue.
The review argues that getting enough total energy and protein is essential before considering specific supplements. The authors suggest a protocol of 10 to 15 grams of gelatin or hydrolyzed collagen with vitamin C, taken 30 to 60 minutes before exercises that load tendons and/or ligaments. This timing is important because vitamin C helps enzymes that build and cross-link collagen, so having both in the bloodstream during exercise may support tissue repair. The review also discusses possible benefits of creatine, omega-3 fatty acids, and adequate micronutrient intake. The authors stress that these strategies should support, not replace, progressive loading. They also note that there is limited direct evidence that collagen supplements speed up return to sport or lower re-injury risk, as most studies are small or use surrogate markers instead of long-term outcomes.
Key Takeaways:
- This narrative review on tendon/ligament rehabilitation nutrition recommends 10–15g of gelatin or hydrolyzed collagen plus vitamin C, taken 30–60 minutes before tendon- or ligament-loading exercise, to support collagen remodeling during the loading window.
- The reason for the timing is that vitamin C is a necessary cofactor for the enzymes which are involved in forming and cross-linking collagen, and therefore taking it together with collagen consumption before starting the loading phase is meant to match up the availability of amino acids and cofactor with the mechanical stimulus that causes tissue remodeling.
- The authors emphasize that taking collagen supplements should be seen as an addition to, not as a replacement for, sufficient energy and protein intake as well as structured rehabilitation loading, and point out that there is still limited evidence showing that it leads to a quicker return to sport or a reduced risk of re-injury.
Access the study: https://doi.org/10.3390/healthcare14142136
Lee, E.-J., & Kim, J. (2026). Rehabilitation nutrition for tendon and ligament injuries: from collagen remodeling to return-to-activity and sport. Healthcare, 14(14), 2136. https://doi.org/10.3390/healthcare14142136