A more comprehensive hormonal diagnosis than has previously been performed shows that androgen-dependent diseases of hair growth are due to more varied hormonal disturbances than elevated androgen serum levels alone. In 46 female patients with androgenic hair loss and 27 patients with hirsutism, the levels of the androgens testosterone, free testosterone, androstenedione, dehydroepiandrosterone sulphate and 17-hydroxyprogesterone and of sex hormone-binding globulin, cortisol, oestradiol and the hypophyseal hormones follicle-stimulating hormone and luteinizing hormone were determined and compared with the hormone levels of 27 female patients without endocrine disorders. Of the androgens, only androstenedione showed a slightly significant elevation in hirsutism. Cortisol was elevated significantly in androgenic hair loss, and with a low degree of significance in hirsutism. In view of the complex hormonal interactions of thyroxin, prolactin and androgens and thyroid hormones the thyrotropin-releasing hormone (TRH)-stimulation test was performed in 38 female patients with androgenic hair loss and 27 with hirsutism, and the results were compared with those recorded in 45 female control persons. The test is based on feedback mechanisms between hypothalamic TRH and hypophyseal TSH and prolactin and peripheral thyroid hormones. Baseline concentrations of TSH prior to stimulation were significantly elevated in hirsutism, while in androgenic hair loss both baseline and stimulated TSH levels were significantly elevated; thus, hypothyroidism is a significant finding in both clinical pictures. In the case of prolactin, both baseline and stimulated levels were highly significantly elevated in hirsutism, while in androgenic hair loss the stimulated levels were significantly elevated.(ABSTRACT TRUNCATED AT 250 WORDS)