SAT-154 - Testosterone Pellet-Induced Androgen Excess Mimicking Hyperthyroidism in A Premenopausal Woman

Testosterone therapy is evidence-based for postmenopausal women with hypoactive sexual desire disorder when maintained within physiologic ranges. Off-label use for nonspecific symptoms such as fatigue lacks evidence and safety data. Long-acting pellet formulations may cause prolonged supraphysiologic testosterone exposure and systemic adverse effects that can mimic other endocrine disorders.

A 35-year-old woman with mild factor VII deficiency presented with 1 month of progressive fatigue, nausea, lightheadedness, restlessness, palpitations, anorexia, exertional dyspnea, and 15-lb unintentional weight loss.

She began testosterone pellet therapy in February 2025 after being told her testosterone was “low” on routine testing for chronic fatigue; baseline total testosterone was 17.1 ng/dL (9-55). Three months after initial pellet placement, total testosterone increased to 108.6 ng/dL with free testosterone 21.9 pg/mL (0.72-7.3) and SHBG 57 nmol/L (18-86). Six months later, she underwent a second pellet insertion. Within 2 weeks, she developed transient bilateral decreased hearing, anxiety, palpitations, sore throat, and voice deepening. Pellets were removed approximately 6 weeks after onset of these symptoms. Two weeks later, hearing and voice normalized and anxiety improved. However, despite pellet removal and initial improvement in androgenic symptoms, she developed delayed clinical deterioration with severe fatigue and functional decline, nausea, poor oral intake requiring a liquid diet, and worsening exertional dyspnea. Thyroid and adrenal evaluation were normal with TSH 0.79 uIU/mL (0.4-4.5), FT4 1.1 ng/dL (0.8-1.8), and AM cortisol 8.6 mcg/dL (4.8-19.2). Gonadotropins were suppressed, consistent with exogenous androgen exposure. Total testosterone declined over subsequent weeks but remained elevated (peak 127 ng/dL), then 84 ng/dL, improving to 44.1 ng/dL 7 weeks after pellet removal. Spironolactone was initiated for androgen blockade, resulting in gradual improvement in symptoms and activity tolerance.

Supraphysiologic testosterone exposure from pellet therapy in women can produce prolonged hypermetabolic symptoms mimicking hyperthyroidism despite normal endocrine axes and may persist or evolve after pellet removal. Avoidance of long-acting formulations, routine biochemical monitoring, and counseling regarding off-label use and risks are essential.

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