In addition to taking a patient’s complete medical history and performing a physical examination, a physician diagnoses male pattern hair loss by observing the total amount of hair on the scalp and analyzing how it is distributed. Men with the condition usually first lose hair on the top of the scalp (crown) and around the temples, making diagnosis relatively routine.

Charts depicting different stages of hair loss may be used in some cases. The Hamilton-Norwood classification chart breaks down the progression of male pattern hair loss into seven classes. Initial hair loss (stages 1 and 2) typically consists of a receding frontal hairline. This recession becomes more defined over the temples and crown area of the scalp in the intermediate period (stages 3-5). Finally, total hair loss over the top, upper sides and back of the scalp characterizes the most advanced progressions of the condition (stages 6-7). Modified versions of the system may be used for patients with different balding patterns.

Additional testing may be performed (e.g., skin biopsy, blood tests) to check if other hair conditions (e.g., alopecia areata, telogen effluvium) or certain illnesses that cause hair loss (e.g., hypothyroidism, hyperthyroidism, iron deficiency) may be responsible or occurring in conjunction with male pattern hair loss. Side effects from other medications a patient may be taking (e.g., anticoagulants, anticonvulsants, beta blockers, antidepressants) can also cause hair loss and should be considered.