Finasteride for hair loss: how it works and what to discuss with a doctor

Finasteride is one of the two most studied medicines for male pattern hair loss, alongside minoxidil. Unlike minoxidil, it is a tablet and it is a prescription medicine. Because it affects hormones, it is worth understanding properly before you start.

How finasteride works

Male pattern hair loss is driven largely by genetics and by dihydrotestosterone (DHT), a hormone made from testosterone. In people who are susceptible, DHT gradually shrinks hair follicles on the top of the head, so hairs become thinner and shorter over time ¹. Finasteride blocks an enzyme called 5-alpha reductase, which lowers DHT levels and may slow this process ^{2 3}.

What the evidence suggests

Systematic reviews find that finasteride 1 mg daily may increase hair counts in men with pattern hair loss compared with placebo ^{4 5}. For many men the main benefit is slowing or stabilising thinning; some also notice improved density, particularly at the crown. As with minoxidil, results vary and need time:

• It usually takes three to six months before any change is seen, and up to a year to judge fully ².
• Benefits last only while you keep taking it. After stopping, hair loss usually returns to its previous course within about a year.

Who it is for

Finasteride for hair loss is used in adult men. It is not used in women who are pregnant or could become pregnant, because it can affect the development of a male baby. Pregnant women should not handle crushed or broken tablets ². Some doctors use related medicines for selected women, but that is a specialist decision. See hair loss in women.

Side effects to know about

Most men who take finasteride do not have side effects, but some do, and they should be discussed openly with a doctor ^{2 6}:

• Sexual side effects such as lower sex drive, problems getting an erection and changes in ejaculation. These were reported in a minority of men in studies ⁷. They usually improve after stopping, but a small number of people report that they continue.
• Mood changes including low mood and depression have been reported. Stop taking it and speak to a doctor straight away if you notice changes in mood or have thoughts of harming yourself ².
• Breast changes such as tenderness or enlargement. Report any lumps or nipple discharge to a doctor.
• Blood test effects. Finasteride lowers PSA, a blood test used in prostate checks, so tell your doctor you take it if you have this test.

Topical finasteride and other options

Finasteride is also being studied as a solution applied to the scalp, which aims to reduce effects elsewhere in the body. Early studies suggest it may help, but long-term evidence is still limited ⁸. Dutasteride, a related medicine, is sometimes used by specialists ⁹. Both are decisions for a doctor.

Finasteride with minoxidil

Because the two work in different ways, they are sometimes used together. Reviews of pattern hair loss treatments discuss combination therapy as an option ¹⁰. Read our guide to minoxidil for more.

Questions to ask your doctor

• Is my hair loss definitely male pattern hair loss?
• What results are realistic for me, and how will we measure them?
• What should I do if I notice side effects?
• Does it interact with my other medicines or health conditions?
• How long should I take it before we review it?

Getting it in Malaysia

Finasteride should be prescribed by a doctor who can assess whether it is suitable and follow up with you. Be cautious of buying tablets online from sellers who do not ask for a prescription or medical history; products from unregulated sources may be fake or mislabelled. A doctor can also check that your hair loss is not caused by something else, such as a thyroid problem or iron deficiency ¹¹. If you have not yet had a diagnosis, start with male and female pattern hair loss explained.

Frequently asked questions

How long does finasteride take to work?

It usually takes three to six months before changes are visible, and up to a year to judge the full effect ².

Are finasteride side effects common?

Most men do not have side effects, but a minority report sexual side effects, and mood changes have been reported ^{7 2}. Discuss any concerns with your doctor.

Can women take finasteride for hair loss?

It must not be used by women who are pregnant or could become pregnant ². Treatment of female pattern hair loss is a specialist decision.

What happens if I stop finasteride?

The benefit gradually wears off, and hair loss usually returns to its previous pattern within about a year.

Educational content. Not medical advice.