Peptides have garnered scientific interest for their potential role in supporting hair growth and combating hair loss or thinning. Peptides are short chains of amino acids that can serve as signaling molecules, influencing various biological processes, including those involved in hair follicle cycling and health. Some specific peptides, such as copper peptides (notably GHK-Cu), have been studied for their ability to stimulate hair follicle growth, reduce inflammation, and promote angiogenesis (formation of new blood vessels) in the scalp. These actions may foster a healthier environment for hair growth.

Several in vitro (cell culture) and animal studies have suggested that certain peptides can increase the size of hair follicles and prolong the anagen (growth) phase of the hair cycle. Limited clinical studies and some small-scale human trials have reported mild to moderate improvements in hair density and thickness with topical peptide treatments. However, most evidence to date remains preliminary, with a lack of large, high-quality randomized controlled trials in humans. The use of peptides in over-the-counter hair serums and products is based on this emerging, but not yet robust, scientific foundation.

In summary, while there is growing scientific rationale and some early evidence supporting the use of peptides for hair loss or thinning, the level of clinical evidence is still low to moderate. More rigorous human research is needed to confidently establish their efficacy.