An overview of incidence and mechanisms promoting weight gain as an adverse effect of oral minoxidil therapy for androgenetic alopecia

Introduction and aim. Androgenetic alopecia, with a mechanism based on the excessive response of hair follicles to androgens, affects a majority of people at some point in their lives, prompting them to seek therapy. Current treatment options for this condition include oral minoxidil, a medication associated with an adverse effect of fluid retention, potentially resulting in weight gain for certain individuals. In contemporary scientific literature, there aren’t many articles focusing solely on this specific side effect. The objective of this review is to explore links between taking oral minoxidil and fluid retention leading to weight gain in patients with androgenetic alopecia by examining available studies in order to understand the mechanisms behind this phenomenon and the dose dependence of fluid retention. Material and methods. A review of the literature was performed to find connections between oral minoxidil therapy and water retention-induced weight gain. Analysis of the literature. Clinical trials have demonstrated that low dose oral minoxidil therapy, within the range of 0.5 to 5 mg daily, leads to an improvement in both hair count and density. The incidence of side effects such as hypertrichosis, fluid retention, headache, dizziness, and insomnia, is relatively infrequent. Fluid retention rates varied between 0.22% in the Tanaka study and 10% of patients in the Panchaprateep study. The discontinuation of treatment was necessary in some instances, with the highest rate of 2.4% cases in the Jimenez-Cauhe study. A comparative analysis of studies on oral minoxidil use for refractory hypertension, within the range of 10 to 40 mg daily, revealed that nearly all patients required adding a diuretic to control fluid retention. Some patients discontinued the treatment due to the severity of side effects. In instances of minoxidil overdose, serious complications, including generalized edema, myocardial infarction, stroke, and pleural effusion, were observed. Across these studies, all patients recovered following the discontinuation of minoxidil treatment. The underlying mechanism behind oral minoxidil induced sodium and fluid retention, contributing to weight gain, is associated with alterations in the neurohumoral system, increased plasma renin activity, changes in renal hemodynamics with relocation of the blood circulation from outer to inner cortex, and tubular effect that can be connected to minoxidil ability to act as an opener of potassium channels in the thick ascending limb of the loop of Henle causing greater reabsorption of sodium and chloride. Conclusion. The frequency and severity of water retention promoting weight gain in individuals taking oral minoxidil are dose dependent. In most patients, minoxidil is a safe and effective treatment option for androgenetic alopecia. In some cases, due to rapid weight gain of 5 pounds or more, adding a diuretic or discontinuation may be required. Further research is necessary to better understand the mechanisms and dose dependence of minoxidil induced fluid retention, which promotes weight gain.