A Short Peptide GPIGS Promotes Proliferation of Hair Bulb Keratinocytes and Accelerates Hair Regrowth in Mice

In a 2005 study, researchers identified a short peptide named GPIGS from Bacillus sp. M18 that promoted hair bulb keratinocyte growth and accelerated hair regrowth in mice. In vitro, GPIGS increased HBK growth by 41-42% at various doses and activated the PI-3K/Akt pathway, with its effect being inhibited by the PI-3K inhibitor LY294002. In vivo, GPIGS treatment led to a faster transition to the anagen phase in mice and a significantly higher hair-regrown area to shaved skin area ratio (39.4±9.6% at 0.03% GPIGS and 73.5±3.6% at 0.1% GPIGS) compared to the control (29.3±8.3%). The study involved five individual cultures for the in vitro tests and eight mice for the in vivo tests, suggesting the potential of GPIGS as a hair growth-promoting agent.