Diet‐Induced Obesity Promotes Alopecia Through Oxidative Stress and Androgen Signalling in Female Mice

ABSTRACT

Female‐pattern hair loss is common in obese women with polycystic ovary syndrome (PCOS), recently proposed as polyendocrine metabolic ovarian syndrome (PMOS) and is often associated with hypertriglyceridemia (TG), although the underlying mechanisms remain unclear. This study investigated how metabolic factors and androgens contribute to hair loss in female mice exposed to a high‐fat diet (HFD). A controlled, parallel‐group study using 8‐week‐old female C57BL/6 mice fed either an HFD (60% kcal fat) or a standard diet for 16 weeks. Mice were sacrificed at baseline and 4‐week intervals for serial evaluation of metabolic, hormonal and skin changes ( n  = 6/group/time point). Hair loss was quantified from digital photographs using the ImageJ and further supported by histological examination. Circulating metabolic and hormonal profiles were measured. In dorsal skin, oxidative stress (malondialdehyde, MDA) and androgen‐related markers—5‐alpha‐reductase type II (5αR2), dihydrotestosterone (DHT) and androgen receptor (AR)—were evaluated using immunohistochemistry, Western blot and enzyme‐linked immunosorbent assay. From Week 12 onward, HFD‐fed mice exhibited greater weight gain, pronounced dorsal hair thinning and elevated TG, insulin and free androgen index (FAI) levels. Skin MDA, 5αR2, DHT and AR levels also progressively increased. In the second experiment, 8‐week‐old female mice were assigned to four groups ( n  = 6/group): HFD with N‐acetylcysteine (NAC), finasteride, spironolactone, or vehicle administered by oral gavage for 12 weeks. Compared with HFD‐vehicle, antioxidant or anti‐androgen co‐treatment significantly lowered serum TG, tissue MDA and ameliorated hair thinning despite similar weight gain and 5αR2 levels. NAC reduced TG, FAI and decreased tissue MDA, DHT and AR. Finasteride lowered TG, MDA, DHT and AR, whereas spironolactone reduced TG and MDA. HFD‐induced obesity exacerbates hair loss in female mice by enhancing oxidative stress and activating androgen signalling in the skin. Targeting these pathways, such as antioxidants and antiandrogens, may mitigate HFD‐accelerated hair loss.