Why the Meta-Analysis Misses Key Context
A closer examination shows important gaps in the meta-analysis. Many of the “independent” trials it relied on were poorly positioned to detect meaningful results – often underdosed (1 – 2.5 g/day, far below the ~5 g/day supported by prior research) or too short in duration (as little as 8 weeks, insufficient for dermal remodeling). These limitations make it unlikely such studies would detect the structural skin changes that collagen can produce.
When collagen is studied under appropriate conditions – proper dosing, at least 12–16 weeks of supplementation, and rigorous trial design – consistent benefits emerge. For example, a 16-week randomized, double-blind, placebo-controlled study published in Nutrients (Žmitek et al., 2024) tested 5 g/day of collagen with vitamin C. The results showed significant improvements in dermal density, skin texture, and wrinkle depth, while hydration and elasticity remained unchanged – a pattern consistent with collagen’s known role in strengthening the dermal matrix rather than altering superficial hydration.
Understanding the Real Takeaway
Even Myung & Park’s own pooled data showed statistically significant improvements in wrinkles, elasticity, and hydration across all studies. Instead of dismissing these results, a better approach is to understand why certain subgroup analyses appear weaker. The answer lies in the details: dose, duration, population, and choice of outcome measures.
The broader scientific takeaway is clear: collagen’s efficacy depends on how it is studied, not simply on whether the research was industry-funded. Declaring collagen ineffective oversimplifies a nuanced body of evidence and risks discouraging further high-quality research. The more productive question is not “does collagen work?” but “which collagen works, for whom, and under what conditions?” When those conditions are met, collagen supplementation remains a promising, evidence-backed approach to supporting skin structure and reducing visible signs of aging.
Read the full review of meta-analysis: Why the Latest Meta-Analysis on Collagen Misses the Mark