Peptides have gained attention for their potential role in supporting hair health, with a growing body of scientific evidence suggesting their benefits. Peptides are short chains of amino acids that can serve as signaling molecules or building blocks for proteins like keratin and collagen, both essential for hair structure and growth. Research has shown that certain bioactive peptides, such as copper peptides (e.g., GHK-Cu), can stimulate hair follicle activity, increase blood flow to the scalp, and extend the anagen (growth) phase of hair. In vitro and animal studies have demonstrated that these peptides can enhance dermal papilla cell proliferation and modulate growth factors relevant to hair cycling.

Human data is more limited but promising. Small clinical studies and topical formulations containing peptides (often in combination with other ingredients) have reported improvements in hair density, thickness, and reduced hair shedding. For example, copper peptide-containing serums have been associated with improved hair appearance and regrowth in some trials, though larger, well-controlled studies are needed. Hydrolized keratin or collagen peptides, when taken orally, have shown some benefits for hair strength and possibly growth, although the evidence is still emerging.

Overall, while the evidence base is not as robust as for FDA-approved hair loss treatments, scientific studies do provide a rationale for the use of specific peptides in supporting hair health, justifying a moderate evidence rating.