The evidence is modestly positive. Hydrolyzed collagen peptide supplementation — typically 2.5-10 g per day for 8-12 weeks — has shown small but statistically significant improvements in skin hydration, elasticity, and dermal collagen density in multiple randomized trials.
The mechanism was initially controversial (dietary collagen is broken down to amino acids and small peptides during digestion), but subsequent research has established that some di- and tri-peptides survive absorption and reach skin fibroblasts, where they appear to signal for increased type I collagen synthesis (Proksch, 2014).
Choi's 2019 systematic review synthesized 19 trials and concluded that collagen supplementation had statistically significant beneficial effects on skin hydration and elasticity (Choi, 2019). Bolke's 2019 randomized controlled trial specifically found improved skin elasticity, moisture, and roughness (Bolke, 2019).
What this doesn't mean:
- The effects are modest — real, measurable, but not transformative.
- The effects reverse when supplementation stops.
- Collagen supplements do nothing for sun damage, glycation, or hormonal collagen loss.
- Diet already contains substantial collagen precursors (protein, vitamin C, zinc).
If you're going to try it: hydrolyzed collagen peptides 5-10 g daily for at least 12 weeks. Address the biological drivers of collagen loss (glycation, inflammation, hormones) in parallel — those have larger effect sizes.