Research summary
How Much Collagen Per Day?
Two systematic reviews with meta-analyses of randomized controlled trials examined daily oral hydrolyzed collagen, most commonly taken over periods up to about 90 days. Pooled results associated supplementation with improved skin hydration and elasticity versus placebo, though the abstracts did not standardize a single gram-per-day amount and the authors flagged study biases.[1], [2]
What the trials actually studied
Across the pooled randomized controlled trials, collagen was given as a daily oral hydrolyzed collagen supplement, with supplementation durations reaching roughly 90 days in the trials that reported skin outcomes. This is the form and timeframe most consistently represented in the meta-analytic evidence rather than a single fixed gram-per-day figure.[1], [2]
What was measured
In meta-analyses combining randomized controlled trials of adults, predominantly women, daily oral hydrolyzed collagen was associated with improved skin hydration and skin elasticity compared with placebo. One analysis of 26 trials reported statistically significant improvements in both hydration and elasticity, and a separate analysis of 19 trials reported favorable effects on hydration, elasticity, and wrinkles over about 90 days. These associations may not apply to every individual.[1], [2]
Limits of the dosage evidence
The pooled abstracts did not converge on a single standardized gram-per-day collagen amount, and the effects on hydration varied by collagen source and supplementation duration. The authors also noted methodological biases in the underlying trials and called for further large-scale randomized controlled trials, so any per-day amount should be read as what was studied, not as a precise recommendation.[1], [2]
Evidence limitations
Both sources are meta-analyses of trials that differed in collagen source, amount, and duration, and the abstracts did not report a uniform daily dose in grams. Participants were predominantly women, and the authors identified biases across the included trials, so the findings are best treated as directional evidence about studied use rather than individualized dosing guidance.[1], [2]
References
- Effects of hydrolyzed collagen supplementation on skin aging: a systematic review and meta-analysis.. International journal of dermatology. 2021. Systematic review and meta-analysis View source →
- Effects of Oral Collagen for Skin Anti-Aging: A Systematic Review and Meta-Analysis. Nutrients. 2023. Systematic review and meta-analysis View source →