Finasteride and dutasteride both treat male pattern hair loss. They belong to the same class, called 5-alpha reductase inhibitors. This page explains how they differ.
At a glance
| Finasteride | Dutasteride | |
|---|---|---|
| Type | Oral 5-alpha reductase inhibitor | Oral 5-alpha reductase inhibitor |
| How it works | Lowers DHT, the hormone that shrinks hair follicles, by blocking one enzyme type | Lowers DHT more, by blocking two enzyme types |
| Used for | Male pattern hair loss | Male pattern hair loss, off-label in Canada |
| Form | Tablet | Capsule |
| How fast it works | Months to see results | Months to see results |
| Common side effects | Lower sex drive, erectile or ejaculation changes, mood changes | Same type of effects, and possibly a bit more often |
| Pregnancy | Women who are or may be pregnant must not handle crushed tablets | Women who are or may be pregnant must not handle the capsules |
| Monitoring | Follow-up check-ins on hair and side effects | Follow-up check-ins on hair and side effects |
Doses are set by your clinician.
How each works
Male pattern hair loss is driven by DHT. This hormone makes hair follicles shrink over time until they stop growing hair. Finasteride blocks one enzyme that makes DHT. That lowers DHT in the scalp and blood and often slows loss.
Dutasteride blocks two forms of the enzyme. It lowers DHT further. For some men, that may mean a stronger effect. We also have less long-term data on dutasteride for hair loss.
Approval in Canada
Finasteride is approved in Canada for male pattern hair loss, at a low dose.
Dutasteride is approved in Canada for an enlarged prostate. Using it for hair loss is off-label in Canada. Off-label means the use is outside the approved label. Clinicians do prescribe this way when they judge it is reasonable.
Your clinician explains this before any prescription and asks for your agreement.
Which may suit whom
Finasteride may suit you if you want the option with the longest track record. It is the usual first choice for most men.
Dutasteride may suit you if finasteride has not helped enough after a fair trial, and you accept the off-label use and the extra unknowns. It is not a first step for most people.
Either medicine suits only men. Your clinician reviews scalp photos, your history, your family history and your mood. Hair loss can also come from other causes, such as thyroid disease or low iron, so your clinician may suggest tests.
Safety and side effects
Most men have few side effects. Some notice a lower sex drive, trouble with erections or less semen. Some report low mood. Tell your clinician about any change in mood or in sexual function. Do not stop on your own without asking, unless you feel unwell.
Women who are or may be pregnant must not handle crushed tablets or open capsules. Both medicines can harm a male baby in the womb.
Can they be used together?
Do not take finasteride and dutasteride together. They act on the same pathway, so the combination adds risk with no clear gain. Your clinician may add other hair loss treatments, such as minoxidil, to either one.
Cost and coverage
The cost depends on the medicine, the pharmacy and the length of use. Each consultation costs CA$175.
Most provincial drug plans do not cover hair loss treatment. Some private plans may. Check your plan. See our insurance page.
Next step
Share scalp photos and your history with Modern Dermatology. A Canadian-licensed medical professional will review them and tell you which option, if any, is right for you.
