Finasteride and dutasteride are both prescription medications that lower DHT, the hormone most responsible for male pattern hair loss. Both can be prescribed as a compounded topical applied to the scalp. This guide explains how they differ, what the evidence does and does not show, and why the choice between them is a provider's decision.
How both medications work
DHT (dihydrotestosterone) is made from testosterone by an enzyme called 5-alpha reductase. In people with pattern hair loss, DHT causes sensitive follicles to shrink over time. Both finasteride and dutasteride are 5-alpha reductase inhibitors, so both lower DHT. Learn more about how finasteride works.
The key differences
- Which enzymes they block. Finasteride mainly blocks the type 2 form of the enzyme. Dutasteride blocks both type 1 and type 2.
- How much DHT they lower. In studies of the oral forms, dutasteride lowers blood DHT levels more than finasteride does (review). How much each topical version lowers DHT depends on the formulation and is less well studied.
- How long they stay in the body. Finasteride clears within hours. Dutasteride has a half-life of several weeks, so any effects, including side effects, can persist much longer after stopping.
- Regulatory status. Oral finasteride is FDA-approved for male pattern hair loss. Oral dutasteride is FDA-approved for an enlarged prostate, and its use for hair loss is off-label. In the United States, neither topical finasteride nor topical dutasteride is an FDA-approved product. Topical versions are prepared by compounding pharmacies on a prescription, and compounded medications are not FDA-approved.
| Finasteride | Dutasteride | |
|---|---|---|
| Enzyme types blocked | Mainly type 2 | Types 1 and 2 |
| Time in the body | Hours | Weeks |
| FDA status for hair loss | Oral form approved; topical not approved | Not approved for hair loss (off-label) |
| Evidence base for hair loss | Extensive for the oral form | Smaller, growing |
What the evidence shows about topical versions
Most of what is known about these medications comes from studies of pills. Research on topical forms is newer and smaller, and studies use different formulations, which makes them hard to compare. There are few head-to-head studies of topical dutasteride versus topical finasteride. Providers weigh this limited evidence alongside a patient's history when deciding what to prescribe.
Does applying it to the scalp change the risk?
The aim of a topical is to act mainly at the scalp and reduce how much medication circulates through the body. That does not mean zero risk. Some medication is still absorbed, and the amount varies by formulation. Because dutasteride stays in the body for weeks, its long half-life is an important safety consideration even in topical form.
Possible side effects of both medications include sexual side effects, mood changes and, with topicals, scalp irritation such as redness or itching. Report any side effects to your provider.
Who should not use them
- People who are pregnant or may become pregnant must not use or handle these medications, because they can cause birth defects in a male fetus.
- Both can lower PSA, a prostate cancer screening test, so tell any doctor ordering that test.
- Because dutasteride lingers for weeks, blood donation restrictions apply during and after treatment.
- Other health conditions and medications need to be reviewed by a provider first.
How a provider chooses
A provider considers your hair loss pattern, how long it has been progressing, what you have already tried, your health history and your goals. Finasteride is often considered first because of its longer track record. A provider may consider dutasteride in other situations, based on their clinical judgment. Hair changes slowly, so providers typically evaluate response over months rather than weeks, and they will tell you how progress will be reviewed.
Frequently asked questions
Is dutasteride stronger than finasteride?
Dutasteride blocks more forms of the enzyme and lowers blood DHT more in oral studies. That does not automatically make it the right choice. Its longer half-life and smaller evidence base for hair loss are part of the decision.
Is topical finasteride FDA-approved?
No. In the United States, oral finasteride is FDA-approved for male pattern hair loss. Topical finasteride is available through compounding pharmacies on a prescription and is not an FDA-approved product.
Can I switch from finasteride to dutasteride?
That is a decision for your provider after reviewing your history and how you have responded so far.
Next step
If you want a licensed provider to review whether either option is appropriate for you, start your online consultation.
Prescription required. A licensed provider decides whether treatment is appropriate. Compounded medications are prepared by a licensed pharmacy for an individual patient and are not FDA-approved. Individual results vary. Prescribed Essence currently serves patients in California, Colorado, Florida and New York.
