Collagen Supplementation on Tendon-Related Structural and Performance Outcomes: A Systematic Review.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials
PubMed 41900537 · doi:10.3390/jfmk11010130
What was done
A systematic review searched PubMed, EMBASE, CINAHL, and Web of Science through May 2025 for randomized controlled trials assessing collagen supplementation combined with exercise in humans. Study quality was evaluated using the PEDro scale. Because of heterogeneity in supplementation protocols, exercise interventions, and outcome measures, findings from 8 RCTs (257 participants aged 18-52; 246 males, 11 females) involving 3-15 weeks of resistance or plyometric training were narratively synthesized without meta-analysis.
What was found
Three of four trials measuring tendon cross-sectional area (CSA) showed significantly greater increases in collagen groups compared with placebo. In four studies assessing tendon stiffness and Young's modulus, the two using higher doses (15-30 g/day) reported significant between-group improvements favoring collagen, whereas two lower-dose studies (~5 g/day) found only within-group changes. Muscle strength improved with training in all trials with no additive benefit from collagen. One study noted improved eccentric rate of force development and deceleration impulse with collagen, but gross explosive performance (e.g., jump height) showed no between-group differences.
Why it matters
This review suggests collagen supplementation may offer dose-dependent benefits for tendon morphological and mechanical properties when combined with mechanical loading, but it does not enhance muscular strength gains.
Limits
Meta-analysis was not feasible due to substantial heterogeneity in dosing, training modalities, and outcome metrics. The total evidence base is small (8 trials, 257 participants), intervention durations were short (3-15 weeks), and the sample was heavily skewed toward males (246 males vs. 11 females), limiting generalizability to females.
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