Procyanidin B-2, extracted from apples, promotes hair growth: a laboratory study

In the 2002 study by A. Kamimura and T. Takahashi, procyanidin B-2, extracted from apples, was found to significantly promote hair growth in murine hair epithelial cells. The compound led to a 300% increase in cell growth over a 5-day culture period compared to controls and was observed to reduce the expression of protein kinase C (PKC) isozymes PKC-α, -βI, -βII, and -n. The study concluded that procyanidin B-2's hair growth-promoting mechanisms might be due to its downregulation of PKC isozymes or inhibition of their translocation, suggesting that PKC isozymes play a crucial role in hair cycle progression. The study implies that procyanidin B-2 could be a potential agent for hair growth promotion, although the sample size and whether the study involved humans or animals were not specified.