Pygeum is a herbal extract from the bark of the African cherry tree. The tree is also known as the African plum tree, or Prunus africanum.

A primary component of Pygeum africanum is Beta-Sitosterol. This is a plant sterol found in avocados, canola oil, cashews, and almonds. Beta-Sitosterol may support healthy hair growth and improve the condition of hair by blocking DHT. Circulation to the scalp is improved, and the Beta-Sitosterol assists oxygen and other vital nutrients reach hair roots and follicles where they are needed.

Research: https://hairgenx.co.za/scientific-research-for-thinning-hair/ para 4.