Context: Erectile dysfuction (ED) is associated with numerous diseases and aging.

Objective: To investigate the impact of hyper- and hypothyroidism on male sexual health by using the Sexual Health Inventory for Males (SHIM).

Design: Seventy-one men, 27 hyper and 44 hypothyroid and a similar number of controls were included in the study. A validated SHIM 5-item questionnaire was administered to all participants. Patients were asked to respond before, and a year after initiation of treatment for thyroid dysfunction. A score between 25–22 is considered normal, between 21–11 diagnostic of mild-moderately severe ED, 10 diagnostic of severe ED.

Results: Fifty-six (78.9%) men with thyroid dysfunction (19 hyperthyroid and 37 hypothyroid) had a SHIM score of 21 or less, compared to 24 (33.8%) controls (P < 0.0001). Twenty-one (37.5%) of patients with ED had SHIM scores 10 indicative of severe ED, compared with 6 (25%) of controls (P < 0.01). ED was more prevalent in patients with hyperthyroidism and hypothyroidism compared to controls (P < 0.001 and P < 0.0001, respectively). Positive correlation was found between SHIM scores and serum FT₄ (r = 0.413, P = 0.005) and negative for TSH (r = -0.669, P < 0.001). After treatment a significant increase of SHIM scores was noted in both hyperthyroid (P < 0.0001) and hypothyroid (P < 0.0001) patients.

Conclusions: ED is extremely common in males with dysthyroidism. Treatment of the latter restores erectile function. Screening for thyroid dysfunction in men presenting with ED is recommended, while specific treatment for ED should be postponed in such patients, for at least 6 months after achieving euthyroidism, as the latter might be responsible for ED.