Cosmetopoeia of African Plants in Hair Treatment and Care: Topical Nutrition and the Antidiabetic Connection?

To make the distinction against pharmaceuticals, natural product medicines are more accurately denoted as nutritional therapies. In the context of topical therapies targeting dermatological conditions, nutritional therapy may explain the mechanism of ethnocosmetic plants used in hair treatment and care. Inspired by emerging theories of a connection between dysregulated glucose metabolism and hair loss, the current review of the literature focused on African plants used to target hair conditions in general, such as alopecia or scalp dermis infections, with a cross-examination of the potential of the species to alleviate issues with glucose metabolism. We distinguish between topical nutrition and sterilization (i.e., dandruff and lice). Sixty-eight plants were identified as an African treatment for alopecia, dandruff, lice, and tinea. Fifty-eight of the species have potential as antidiabetic treatments when taken orally. The family Lamiaceae was the most represented (six spp.), followed by Fabaceae and Asteraceae (five spp. each). Most species are herbs, and the most used plant part is the leaf. Thirty of the sixty species have research associated with hair growth and general hair care, with studies focused on 5 alpha-reductase inhibition, biomarkers such as vascular endothelial growth factor, and the rate of telogen to anagen phase transition. While studies tend to conceptualize the mechanisms of these medicinal species similarly to pharmaceuticals, the current review argues that a nutritional interpretation is more appropriate, where a general improvement to local glucose metabolism may play a role.