Androgenetic Alopecia (AGA), also known as male-pattern hair loss or as female-pattern hair thinning, is the most common form of hair loss in humans. Onset may occur in either sex at any time after puberty and the majority of thinning occurs in the teens, 20s, and 30s. The cause of AGA is a gradual shrinkage of the hair follicle which occurs under the influence of androgen hormones. Basically, the 5-alpha reductase enzyme converts testosterone to dihydrotestosterone (DHT) in scalp hair follicles. In genetically susceptible scalp hair follicles, DHT causes the gradual transformation of large hair follicles to a finer and shorter hair (this process is called “miniaturization”). Women with AGA usually first notice a gradual thinning of their hair, mostly on the central scalp, and their scalp becomes more visible. The patient may notice that her “ponytail” is much smaller. This widespread thinning of the scalp can vary in extent, but it is extremely rare for a woman to become bare on top. Examination of the scalp will show a patterned hair loss with the frontal hairline usually intact but thinning mostly on the central scalp. Although androgens play an important role in AGA, levels of circulating androgens in men or women with AGA are usually normal. Thus, extensive laboratory tests are usually not needed if the woman with AGA has normal menses, pregnancies, and endocrine function. Minoxidil topical solution (Rogaine®) is the only medication indicated for promoting hair growth in women with AGA, resulting in increase hair counts and total hair weight (i.e. re-enlarge the fine hairs). Women with AGA may also consider Spironolactone (Aldactone®) which has less evidence to back its efficacy, but might be a good choice in women with excess body hair. Finasteride (Propecia®) is a medication (5-alpha reductase inhibitor) that decreases levels of DHT. Although it is the most effective treatment of AGA in men, it is NOT FDA-approved for women. Finasteride therapy for female-pattern hair loss has also been studied and has been shown to result in significant improvement in hair density and hair thickness at higher medication doses. It is therefore sometimes prescribed off-label. Pregnancy must be ruled out before initiating therapy and women should be maintained on strict birth control during treatment because it may pose a risk to the fetus. Surgical options include hair transplantation where hair follicles are surgically moved from the “donor” occipital scalp (which is less susceptible to the effects of androgen hormones) to the thinned “recipient” areas. Nonsurgical options include the use of camouflage techniques, such as creative coiffures (tinting, waving, and teasing) and scalp covers (hair piece, powders or creams). In order to determine what the best treatment options are for you, I recommend a consultation with a hair specialist.