The human scalp harbors a vast community of microbiotal mutualists. Androgenetic alopecia (AGA), a most common form of hair loss in males, is a multifactorial condition involving genetic predisposition and hormonal changes. The role of microflora during hair loss remains to be understood. Here, we investigated bacterial communities in 12 healthy and 12 AGA subjects at baseline and after 84 days of treatment by Lindera strychnifolia roots extract (LsR). Using a phototrichogram, we also compared hair density and total hair counts in 17 subjects receiving LsR treatment at baseline and after 83 days of treatment.
The analysis of bacterial distribution at the genus level showed no modifications between healthy and AGA groups. Higher C. acnes/S. epidermidis ratio in AGA subjects compared to control ones was noted. Concerning the mycobiota environment, lower abundance of Basidiomycota and higher proportion of Ascomycota, associated with lower proportion of Malassezia genus and increase of other fungal genus (Wallemia, Eurotium), implicated in the hair loss process, were observed in AGA scalp. Finally, lower proportion of M. globosa and M. restricta were observed. Therefore, data from sequencing profiling of the scalp microbiota strongly support a different microbial composition between normal and AGA affected the scalp. 84 days treatment with LsR extract rebalances bacteriota and mycobiota for a healthy scalp. A significant increase in hair number that reach +6.9% compared to Day 0 (p=0.002) was observed in the 17 subjects. At this time point, 71% of men had an improvement of hair density. Based on these results, we conclude that the LsR extract is a promising remedy for preventing hair loss and promoting hair growth.