Polygonum, particularly Polygonum multiflorum (also known as He Shou Wu or Fo-Ti), has a long history of use in Traditional Chinese Medicine (TCM) for supporting hair health and promoting hair growth. According to TCM records dating back centuries, He Shou Wu is believed to nourish the liver and kidneys, which are considered vital for maintaining healthy hair in traditional theory. It is commonly used in formulas intended to prevent hair loss, restore hair color, and improve hair vitality, especially in cases of premature graying or thinning.

Regarding scientific evidence, there are a few preclinical studies (mainly in vitro or animal models) suggesting that extracts from Polygonum multiflorum may promote hair growth by prolonging the anagen (growth) phase of hair follicles and modulating certain signaling pathways. However, rigorous human clinical trials are lacking, and the available scientific data is not robust enough to conclusively validate its efficacy for hair support. Most claims about its effects on hair are based on traditional use and anecdotal reports rather than solid clinical evidence.

In summary, the use of Polygonum for supporting the hair body system is primarily justified by traditional practices, with limited scientific support. Caution is also advised, as some reports have linked excessive use of Polygonum multiflorum to potential liver toxicity.