Dutasteride for hair loss: how it compares with finasteride

If you have researched finasteride, you may have come across dutasteride. Both belong to a group of medicines called 5-alpha reductase inhibitors. Dutasteride is mainly licensed for an enlarged prostate, and in many countries its use for hair loss is off-label, meaning a doctor prescribes it outside its main licensed use. Here is what you should know before discussing it.

How it differs from finasteride

Both medicines lower dihydrotestosterone (DHT), the hormone that shrinks hair follicles in male pattern hair loss ¹. The key differences are:

• Broader action: the body has two main forms of the 5-alpha reductase enzyme. Finasteride mainly blocks one, while dutasteride blocks both
• Stronger DHT reduction: as a result, dutasteride lowers DHT levels further
• Longer-lasting: dutasteride stays in the body much longer after the last dose, which matters for side effects and blood donation ²

What the evidence shows

A systematic review and meta-analysis of three randomised trials, including 576 men, compared dutasteride with finasteride over 24 weeks. Dutasteride gave a greater increase in total hair counts and better scores on photo assessments ³. The review found no significant difference in rates of sexual side effects between the two medicines in these trials.

The evidence base is smaller than for finasteride, and most trials were short. Guidelines tend to place dutasteride as an option to consider when finasteride has not helped enough, rather than as a first choice ⁴.

Side effects

Side effects are similar to those of finasteride:

• Lower sex drive, erection problems and ejaculation changes ²
• Breast tenderness or enlargement
• Rarely, allergic reactions

A meta-analysis of placebo-controlled trials in men with hair loss found an increased risk of sexual dysfunction with this group of medicines, although for dutasteride the increase was not statistically significant because few studies were available ⁵. Mood changes have been reported with this class of medicines; tell your doctor promptly if your mood changes. Read finasteride side effects for a fuller discussion.

Practical cautions

• Blood donation: you should not donate blood while taking dutasteride and for six months after stopping, so that a pregnant woman does not receive it ²
• Pregnancy: dutasteride is for use only in men. Women who are or may become pregnant should not handle the capsules, as the contents may harm a male fetus ²
• PSA tests: like finasteride, dutasteride lowers PSA levels. Tell any doctor checking your prostate that you are taking it
• Swallow whole: capsules should not be chewed or opened

Who may be offered it

A doctor may consider dutasteride if:

• You are a man with confirmed pattern hair loss
• Finasteride has not given enough benefit after a fair trial
• You understand that use for hair loss may be off-label
• You have discussed the side effects and the longer time it stays in the body

It is not usually used in women of childbearing potential. Women with hair loss can read minoxidil for women.

Using with minoxidil

Like finasteride, dutasteride works on DHT, while minoxidil supports the follicle in a different way. Doctors may combine them for some men. Our article on minoxidil and finasteride together explains the logic of combining medicines that act differently.

Mesotherapy with dutasteride

Some clinics offer small injections of dutasteride into the scalp. Evidence for this approach is limited, and the methods and doses vary between studies. If offered, ask about the evidence, the number of sessions, side effects and total cost.

Timeline and commitment

As with finasteride, results take months. A fair review point is often 6 to 12 months. Benefits last only while you take it. Because dutasteride lingers in the body, side effects may take longer to settle after stopping than with finasteride.

Questions to ask your doctor

• Why are you suggesting dutasteride rather than finasteride?
• Is this use off-label here, and what does that mean for me?
• Which side effects should I watch for, and what if they occur?
• How will we measure whether it is working?
• What should I know about blood donation and PSA tests?

The bottom line

Dutasteride lowers DHT more strongly than finasteride and may give more benefit for some men, but it has a smaller evidence base, similar side effects and some extra cautions. It is a decision to make with a doctor. For background, read finasteride in Malaysia.

Frequently asked questions

Is dutasteride better than finasteride for hair loss?

A meta-analysis of three trials found greater hair count increases with dutasteride over 24 weeks ³, but the evidence base is smaller.

Does dutasteride have more side effects?

The same review found no significant difference in sexual side effects between the two medicines ³. Both can cause them.

Can I donate blood on dutasteride?

No. You should not donate blood while taking it and for six months after stopping ².

Can women take dutasteride?

It is for use only in men, and pregnant women should not handle the capsules ².

Educational content. Not medical advice.