Peptides, particularly collagen peptides, have been studied for their potential role in supporting nail health. Collagen is a structural protein that is abundant in connective tissues, including the nails. Oral supplementation with collagen peptides has been shown in several studies to improve nail growth rate, decrease the frequency of broken nails, and enhance nail appearance. For example, a 2017 open-label study published in Journal of Cosmetic Dermatology found that daily supplementation with bioactive collagen peptides for 24 weeks increased nail growth by 12% and decreased the frequency of broken nails by 42%. The proposed mechanism is that collagen peptides provide essential amino acids and stimulate the body’s own production of collagen, which may benefit the nail matrix and the surrounding tissue. However, while these results are promising, most studies to date are small, open-label, or industry-sponsored, and there is a need for larger, placebo-controlled trials to confirm efficacy and elucidate mechanisms. While peptides other than collagen (e.g., keratin peptides) have been less studied, the bulk of the evidence for nail support centers on collagen-derived peptides. Thus, the use of peptides to support the nails is supported by preliminary scientific evidence, but is not yet conclusively proven.