Topical metformin as a novel therapy for alopecia areata due to its immunologic effects

Alopecia areata (AA) is an autoimmune and inflammatory hair follicle disorder. Environmental and inherited factors may both contribute to this condition. Numerous studies have indicated that metformin has antiinflammatory and immunomodulatory properties. The medication can potentially reduce inflammation as it can inhibit some inflammatory pathways, such as nuclear factor kappa B (NF-kappa B), as well as effector cell proliferation, inflammatory cytokine production, and cytokine receptor signaling pathways. Metformin can also mitigate autoimmune reactions by increasing the percentage of regulatory T cells (Tregs). Aside from having a relatively small number of side effects, this medicine has shown efficacy in managing other autoimmune conditions, such as Sjogren's syndrome and Systemic Lupus Erythematosus (SLE). Studies have indicated that metformin stimulates autophagy and stem cell proliferation in hair follicle cells, which are important for hair regrowth. Metformin has been shown to stimulate hair growth both in vivo in cicatricial alopecia and in vitro settings. Metformin characteristics make it appropriate for evaluation in the treatment of alopecia areata. In this study, we reviewed several metformin properties that make it a suitable choice for treating autoimmune diseases and hair regeneration, and we hypothesized that topical metformin, as an anti-inflammatory and immunomodulatory medication, can be beneficial in the treatment of alopecia areata.