Adults over 50 who took 15 grams of collagen peptides daily for 12 weeks lost body fat while the placebo group gained it, without changing their diet or exercise habits.
-0.49% vs +2.23%Change in total body fat mass over 12 weeks — collagen group lost fat while placebo group gained it (p=0.041)
What the researchers found
Older adults (≥50 years) who took 15 grams of low-molecular collagen peptides daily for 12 weeks experienced a significant reduction in body fat mass compared to placebo, confirmed by two independent measurement methods (BIA and DEXA).
The collagen group saw a -0.49% change in total fat mass while the placebo group gained 2.23% (p=0.041). Within the collagen group, significant reductions were observed in whole body fat mass (p=0.002), whole body fat percentage (p=0.002), trunk fat mass (p=0.001), and trunk fat percentage (p<0.001). Importantly, physical activity levels, dietary intake, and blood biochemistry did not differ between groups, suggesting the effect was from the collagen supplementation itself.
Why it matters
Age-related fat gain — especially around the trunk — is a major health concern for older adults, contributing to cardiovascular disease, diabetes, and mobility issues. If collagen peptide supplementation can meaningfully reduce body fat without requiring changes to diet or exercise, it would represent a simple, accessible intervention. This trial adds to growing evidence that collagen peptides may have metabolic effects beyond their well-known benefits for skin and joints.
The numbers in context
n=74 · 12 weeks · 15 g/day collagen peptides · Fat mass change: -0.49% vs +2.23% (p=0.041) · BIA p=0.021 · DEXA p=0.041 · Whole body fat mass p=0.002 · Trunk fat mass p=0.001
How the study worked
Randomized, double-blind, placebo-controlled trial with 74 adults aged 50 and older. Participants were assigned to receive either 15 g/day of low-molecular collagen peptide or a placebo drink for 12 weeks while maintaining their normal physical activity levels. Body composition was measured using both bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DEXA). Physical activity, dietary intake, and blood biochemical markers were also monitored.
Who was studied
74 adults aged 50 years and older, maintaining daily physical activity levels, randomized to collagen peptide (n=37) or placebo (n=37)
What this study cannot tell us
The sample size of 74 is relatively small. The 12-week duration doesn't reveal whether fat loss continues, plateaus, or reverses after stopping supplementation. The specific mechanism by which collagen peptides reduce body fat is not explained. BIA can be influenced by hydration status. Published in a smaller journal (Clinical Nutrition Research) rather than a high-impact journal. The collagen peptide product specifics (brand, amino acid profile) may affect reproducibility.
How to read the evidence
This is a randomized, double-blind, placebo-controlled trial — good study design. However, the sample size is small (74) and the journal is lower-impact. The findings are promising but need replication in larger studies to reach strong evidence status.
When this study was published
Published in 2023. This is recent research and adds to a growing body of evidence on collagen peptide supplementation effects beyond skin and joint health.
The bigger picture
Collagen peptides are primarily marketed for skin, joint, and bone health. This trial adds body composition to the list of potential benefits, which could significantly expand the appeal of collagen supplementation for aging populations. If replicated in larger studies, it suggests collagen peptides may have metabolic effects — possibly by influencing satiety signaling, muscle mass preservation, or fat metabolism — that go beyond structural protein support.
Questions still open
- What is the biological mechanism by which collagen peptides reduce body fat — is it through satiety, thermogenesis, muscle preservation, or something else?
- Would a longer trial show continued fat loss, or does the effect plateau after 12 weeks?
- Does the molecular weight or source of collagen peptides matter for the body composition effect?
Common questions
How much collagen peptide was used and how was it taken?
Did people have to change their diet or exercise to see results?
Read the original research
Low-Molecular Collagen Peptide Supplementation and Body Fat Mass in Adults Aged ≥ 50 Years: A Randomized, Double-Blind, Placebo-Controlled Trial.
Clinical nutrition research, 12(4), 245-256
Citation
Park, Jeongbin; Kim, Minji; Shin, Hyeri; Ahn, Hyejin; Park, Yoo Kyoung. (2023). Low-Molecular Collagen Peptide Supplementation and Body Fat Mass in Adults Aged ≥ 50 Years: A Randomized, Double-Blind, Placebo-Controlled Trial.. Clinical nutrition research, 12(4), 245-256. https://doi.org/10.7762/cnr.2023.12.4.245