AT A GLANCE

A multi-method study implicates gut microbiota in androgenetic alopecia, showing that restoring Lactobacillus species via FMT or probiotics can reduce follicular inflammation and promote hair regrowth.

The interplay between the gut microbiome and skin health is increasingly recognized, and new data suggest this connection may extend to androgenetic alopecia (AGA). In a multi-method study combining Mendelian randomization, microbiome sequencing, and metabolomic profiling, researchers identified a protective role for Lactobacillaceae in hair biology.

Genetic analysis demonstrated a significant inverse association between AGA risk and the abundance of both Lactobacillaceae (OR = 0.981, p = 0.001) and Lactobacillus (OR = 0.985, p = 0.018). In mouse models of AGA, these taxa were markedly reduced in fecal samples. Restoration of gut flora via fecal microbiota transplantation (FMT)increased Lactobacillaceae abundance, while administration of Lactobacillus rhamnosus GG (LGG) further reversed markers of inflammation and cellular aging in both the colon and hair follicles. Functional readouts—including dermoscopic evaluation—confirmed significant improvement in hair regrowth following LGG treatment.

The findings support the concept of an intestinal–skin axis in AGA, in which dysbiosis and metabolic dysregulation contribute to follicular aging and inflammatory cascades. By modulating gut flora, FMT and probiotic interventions may represent novel adjunctive strategies for promoting hair regrowth. While clinical validation in humans is required, these results provide mechanistic insight into how microbiome-targeted therapies could reshape treatment approaches for hair loss disorders.