One hundred women who presented with diffuse alopecia, were quantitatively evaluated for hair variables and compared with 20 controls. Fifty were selected for biochemical and haematological investigations, 44 of whom also underwent endocrine evaluation. Compared to controls, significant changes in hair values were found in the frontal area of all subjects, while 84% had significant changes in the occipital area. A biphasic distribution of hair diameter was evident in subjects who had percentages of vellus hair and telogen hair less than or equal to 30 mm in length that were above the control ranges. No significant difference between the mean hormonal values of women with diffuse alopecia and controls could be found. No correlation between hair values and individual or combined hormonal levels could be established. In 18 subjects (40.9%) hormonal values were within the control ranges and these apparently normal findings were often associated with adverse hair profiles. A raised dihydrotestosterone was found in 13 subjects (29.5%) and was the most frequently elevated androgenic finding. Seventeen (34.0%) had changes in iron metabolism, while in 36 (72.0%) serum ferritin levels were below the lowest control value. All had a decrease in the percentage of hair in the anagen growth phase compared to controls. The hair changes were similar to those observed in genetic hair loss in men, a proven androgen-dependent condition. We propose that diffuse androgen-dependent alopecia is the appropriate name to describe this condition in these women.