Pituitary Effects of Metformin in Men With Early‐Onset Androgenic Alopecia

Abstract

Males with early-onset androgenic alopecia are characterized by elevated androgen levels. The aim of the present study was to investigate whether the presence of this condition modulates the impact of metformin on pituitary hormone production. This study compared 2 groups of young men with prediabetes, matched for age, blood pressure, and insulin sensitivity: 23 subjects with early-onset male-pattern baldness (group 1) and 25 individuals with normal hair growth (group 2). Throughout the study, both groups were treated with metformin for 6 months. Circulating levels of glucose, insulin, glycated hemoglobin, gonadotropins, thyrotropin, prolactin, adrenocorticotropic hormone, insulin-like growth factor-1 and androgens were determined at the beginning of the study and 6 months later. At entry, luteinizing hormone (LH), the LH/follicle-stimulating hormone ratio, total testosterone, bioavailable testosterone, adrenocorticotropic hormone and dehydroepiandrosterone sulfate were higher in group 1 than in group 2. The effect of metformin on fasting glucose, insulin sensitivity, and glycated hemoglobin was more pronounced in group 2 than in group 1. Only in group 1, metformin reduced LH levels and the LH/follicle-stimulating hormone ratio. Metformin did not affect plasma levels of the remaining hormones. In untreated men with androgenic alopecia (group 3, n = 22), glucose homeostasis markers and hormone levels remained similar throughout the study period. The obtained results suggest that the impact of metformin on gonadotroph secretory function is stronger in men with early-onset androgenic alopecia than in men with normal hair growth. Metformin treatment may protect men with early-onset androgenic alopecia against the development of gonadotroph hyperplasia and/or focal testicular changes.

Impaired Prolactin-Lowering Effects of Metformin in Women with Polycystic Ovary Syndrome

“…This observation is in line with the results of previous studies including male subjects. In individuals with early-onset male-pattern hair loss, considered the equivalent of PCOS in men [28], metformin produced a neutral effect on plasma prolactin [29], while in hypogonadal men with prolactin excess, the decrease in plasma prolactin was observed only in patients not receiving exogenous testosterone [22]. The current study is the first to show similar relationships between hyperandrogenism and the absence of prolactinlowering properties in women.…”

Factors associated with early-onset androgenetic alopecia: A scoping review

“…These were all case-control studies. The results showed that men with early-onset AGA may experience less benefit from rosuvastatin [ 64 ], metformin [ 65 , 66 ], lisinopril [ 67 ], levothyroxine [ 68 ], Vitamin D [ 69 ], or bromocriptine [ 70 ] when treating dyslipidemia, prediabetes, hypertension, autoimmune hypothyroidism, autoimmune thyroiditis, or prolactin excess, respectively, compared to the contemporaries without alopecia. However, one exception was noted, as the impact of metformin on gonadotroph secretory function appeared to be stronger in men with early-onset AGA compared to those with normal hair growth [ 66 ].…”

“…Therefore, this emphasizes the importance of lifestyle modifications in individuals with early-onset AGA to prevent these co-existing health conditions. Furthermore, men with early-onset AGA may benefit to a lesser degree from treatments such as rosuvastatin [ 64 ], metformin [ 65 , 66 ], or lisinopril [ 67 ] compared to individuals with normal hair growth. Therefore, young patients with AGA may not only be more susceptible to developing metabolic diseases, but also less responsive to certain treatments.…”