Finasteride for Hair Loss: What the Label Actually Covers

Yes, as a tablet. The Propecia label says it's approved to treat male pattern hair loss in men only, and that it isn't for use in women.

There's no FDA-approved topical finasteride, alone or combined with other ingredients. Topical finasteride is compounded, and compounded medicines aren't FDA-approved, which means the FDA hasn't evaluated their safety, effectiveness or quality before they're marketed. A compounded topical doesn't come with FDA-approved labeling of its own, so follow your prescription and the pharmacy's instructions.

From the Propecia prescribing information, Clinical Studies. Two studies enrolled 1,553 men ages 18 to 41 with mild to moderate hair loss mostly at the crown, and 1,215 continued into a second year. The 66% figure is an independent panel's rating of standardized photos (7% on placebo), not a 66% increase in hair count.

The 83% figure is the share of men whose hair count didn't go down at two years (100% minus the 17% who had a decrease; 72% on placebo had a decrease). Hairs were counted in a 1-inch circle at the crown, not the whole head.

The 66% and 83% results are for the approved tablet taken daily, not a topical, and the studied dose isn't a dosing instruction. Results need continued treatment and vary: men who switched to placebo after the first year no longer had their hair-count gain 12 months later.

More men improved with finasteride and minoxidil together than with minoxidil alone, in both studies. In one study, 160 Chinese men took a daily finasteride tablet plus topical 5% minoxidil, and 152 were evaluated at 12 months.

Of those men, 94.1% showed improvement, compared with 80.5% on finasteride alone and 59% on minoxidil alone. That was a two-product regimen, not a test of a compounded topical blend.

In another study, adult men applied a solution of 5% minoxidil and 0.1% finasteride twice daily for 24 weeks.

By photo assessment, 88.9% had slightly, moderately or greatly increased growth, compared with 60.0% using minoxidil alone. That studied formulation isn't every compounded strength or base, including Liv's, and study doses aren't dosing instructions.

It contains the same active ingredient as the tablet, and the FDA expects it to be absorbed through the skin into the bloodstream.

The FDA has received reports of side effects with compounded topical finasteride. They were similar to those reported with the approved tablets, and most reports said they continued after the product was stopped.

A topical can also cause scalp irritation, redness, dryness, stinging or burning. Because it has no tablet coating, the FDA notes a greater chance of it transferring to other people, especially women. The FDA recommends that providers talk with patients about these risks, so bring any questions to your provider.

It's for men only. The label says it isn't for women who are or may become pregnant, because it may cause abnormalities of the genitals of a male fetus, or for anyone allergic to any of its ingredients.

Women who are pregnant or may become pregnant shouldn't handle crushed or broken tablets. Intact tablets are coated, which keeps the medicine off the skin during normal handling. With a topical, take care to keep it from touching other people.

Yes. Finasteride lowers PSA levels, a blood test used to check the prostate, so tell your provider you take it before a PSA test. The label says any confirmed rise from your lowest PSA while on it should be checked, even within the normal range.

The label also carries a warning about a more serious form of prostate cancer, from a study of a higher-strength finasteride tablet, so your provider watches any change in your PSA. If you haven't been taking finasteride as prescribed, say so too, because that can also affect your results.

The most common are lower sex drive, trouble getting an erection and problems with ejaculation, as listed on the label.

Don't assume symptoms will stop when treatment ends. Discuss these risks with your provider, and tell them about any change you notice.

The label covers male pattern hair loss, and its studies counted hair at the crown and the front-middle of the scalp. Your provider can talk with you about what to expect at the temples and front hairline.