Topical finasteride: what it is and what is still unknown

Finasteride tablets are one of the main medical treatments for male pattern hair loss. Some men are put off by worries about side effects, which has led to growing interest in a version applied directly to the scalp. Topical finasteride is now prescribed in some places and compounded by some pharmacies, but what do we actually know?

How finasteride works

In pattern hair loss, a hormone called dihydrotestosterone (DHT) causes genetically sensitive follicles to shrink over time. Finasteride blocks an enzyme (5-alpha reductase type 2) that turns testosterone into DHT, lowering DHT levels ¹. Oral finasteride 1 mg is a well-studied treatment for men with pattern hair loss ^{2 3}.

Why a topical version?

Oral finasteride is generally well tolerated, but a small proportion of men report side effects such as reduced sex drive, erectile problems or mood changes ³. The hope with topical finasteride is to concentrate the drug's effect in the scalp while reducing how much enters the bloodstream, and so possibly reduce side effects.

What the studies show

A 2018 systematic review in the Journal of Drugs in Dermatology included seven studies of topical finasteride in men and women ⁴. It found:

• In all studies, topical finasteride was associated with a decrease in the rate of hair loss, an increase in total and terminal hair counts, and positive hair growth assessments.
• Both scalp and blood DHT levels fell with topical use.
• No changes in blood testosterone were seen.
• The authors described the results as preliminary, limited, but safe and promising.

They also listed what still needs research: the best way to deliver the drug, the ideal concentration, how often to apply it, side effects, and use in other types of hair loss ⁴.

What is still unknown

1. How much reaches the bloodstream?

The finding that blood DHT also falls shows that topical finasteride is not purely local ⁴. How much it is absorbed depends on the concentration, the amount applied, the area covered and the formula. This means side effects are still possible.

2. What is the right strength and routine?

Studies have used different concentrations and schedules. There is no single agreed standard, and compounded products may vary.

3. Is it as effective as tablets?

Some studies suggest similar results, but long, large, head-to-head trials are limited.

4. Long-term safety

Long-term data, especially over many years, are still being gathered.

5. Use in women

Finasteride is not usually recommended for women who could become pregnant, because it may affect the development of a male baby ³. Some doctors consider it for selected women after menopause, but evidence is limited.

Practical safety points

• Use only under medical advice. Finasteride is a prescription medicine.
• Protect others. Avoid skin contact between treated scalp and partners or children until the product has dried, and wash your hands after applying. Women who are or may become pregnant should not handle finasteride products ³.
• Watch for side effects and report them to your doctor, including changes in sexual function or mood.
• Be patient. Like other hair treatments, any effect takes months to judge.
• Tell your doctor about any prostate tests, because finasteride can affect PSA results.

Topical finasteride and other treatments

Topical finasteride is sometimes combined with minoxidil in the same solution. Combining treatments that act in different ways is a common approach (see combining hair loss treatments). However, combination products made by compounding pharmacies are not all tested in the same way, so ask about the source and strength.

Who might consider it?

A doctor might discuss topical finasteride with men who:

• have a confirmed diagnosis of male pattern hair loss
• want a DHT-lowering treatment but are concerned about oral side effects
• have had side effects on oral finasteride (although they may still occur with topical use)

It is not a substitute for a proper diagnosis. Hair loss with patches, scalp redness, scaling, pain or sudden shedding needs assessment first.

The bottom line

Topical finasteride is a promising option that lowers scalp DHT and has shown benefits in early studies. But it is not completely free of systemic effects, and there is still uncertainty about dose, long-term safety and how it compares with tablets. Discuss it with a doctor who can weigh your options. For an overview of evidence-based options, see male pattern baldness treatment overview.

Frequently asked questions

Does topical finasteride work?

A 2018 review of seven studies found it reduced hair loss and increased hair counts, but described the evidence as preliminary ⁴.

Does topical finasteride have fewer side effects than tablets?

That is the aim, but blood DHT still falls with topical use, so side effects remain possible ⁴.

Can women use topical finasteride?

Women who are or could become pregnant should not use or handle finasteride ³. Any use in women needs specialist advice.

Can I mix finasteride and minoxidil?

Some products combine them. Discuss it with a doctor and ask about the source and strength of any compounded product.

Educational content. Not medical advice.