JCD: Evidence for the Skin Benefits of Collagen Supplements Found to Be Flawed
13:42 8 October, 2026Evidence that collagen supplements improve skin health has been called into question after researchers identified serious methodological flaws in key scientific reviews on the subject. This was the conclusion reached by biostatistician David Robert Grimes of Trinity College Dublin and UK-based dermatologist Anjali Mahto. Their study was published in the Journal of Cosmetic Dermatology.
The authors re-examined two influential meta-analyses published in 2021 and 2023 that are frequently cited as evidence of collagen's benefits. They identified statistical errors and incorrectly reported results. After correcting these issues, they found no clear relationship between collagen dosage and improvements in skin hydration or elasticity.
The researchers identified numerous problems with the underlying studies. Most were funded by collagen manufacturers or conducted by authors with commercial ties to the industry. The doses used across trials varied 30-fold, ranging from 0.3 to 10 grams per day. The trials themselves lasted only 8–12 weeks, and collagen was often combined with other active supplements, making it impossible to determine which ingredient was responsible for any observed effects. Another concern was collagen's distinctive taste and texture, which may have allowed participants to guess which group they belonged to, potentially compromising the blinding of the experiments.
“Collagen may yet find a role in dermatology, but promoting it as a proven anti-aging treatment is premature and scientifically unjustified at present,” the researchers concluded.
This does not mean that collagen is useless; rather, convincing evidence of its effectiveness is currently lacking. The authors advise dermatologists to refrain from recommending these supplements until rigorous, independent trials provide evidence of their benefits.