Dutasteride Twice or Three Times Weekly vs Daily Finasteride: 2025 Pilot RCT Research Summary
This is a plain-language summary of the original published research. We do not add conclusions or opinions of our own. This is not medical advice — consult a certified healthcare practitioner before making any decision.
Original research published in JAAD International, 2025
Dutasteride Twice or Three Times Weekly vs Daily Finasteride
Study conclusion
Small pilot trial of 60 men tested whether dutasteride 0.5mg two or three times per week could increase hair growth while potentially reducing side effects vs daily finasteride. All three regimens increased hair density and diameter significantly. Three-times-weekly dutasteride showed greater improvement than twice weekly but did not significantly outperform daily finasteride in hair count.
Strength of evidence
This was a randomised investigator-blinded pilot trial. The score is limited because the sample was only 60 men, it was conducted at a single centre, the trial was not blinded to participants, and dutasteride is not FDA-approved for hair loss. Pilot studies are by design preliminary.
Who it applies to
Who was studied
Men aged 21–60 with mild to moderate pattern hair loss. 60 participants randomised equally. Dutasteride 0.5mg twice weekly, dutasteride 0.5mg three times weekly, or finasteride 1mg daily for 24 weeks.
Who was NOT studied
Women. Men with severe hair loss. People using higher or different dosing schedules.
What to look for when shopping
Dutasteride is not FDA-approved for hair loss. Finasteride 1mg is the only FDA-approved oral treatment. Both are prescription-only.
What research cannot help you decide
Whether intermittent dutasteride reduces sexual side effects vs daily finasteride. The trial was not powered to detect side effect differences.
Key findings
- All three regimens significantly increased hair density and diameter from baseline
- Dutasteride three times weekly showed greater improvement in hair density and diameter than twice weekly
- Dutasteride three times weekly did not significantly outperform daily finasteride in total hair count
- Mean terminal hair count increase was 17.43 hairs/cm² for 3x/week dutasteride vs 12.81 hairs/cm² for daily finasteride
- Sexual side effects were similar across all three groups
What they did
Researchers randomly assigned 60 men with mild to moderate pattern hair loss to dutasteride 0.5mg twice weekly, dutasteride 0.5mg three times weekly, or finasteride 1mg daily for 24 weeks at a single Thai university hospital. Hair density and diameter were measured using videodermoscopy. Investigators were blinded to treatment allocation; participants were not.
What they found
| Comparison | Result | Significant? |
|---|---|---|
| Dutasteride 3x/week vs finasteride daily — hair count | Non-significantly higher with dutasteride (17.43 vs 12.81 hairs/cm²) | No |
| Dutasteride 3x/week vs 2x/week — hair density and diameter | Significantly better with 3x/week | Yes |
| All three groups vs baseline — hair density | All three showed significant improvement | Yes |
| Sexual side effects — all groups | Similar across all three regimens | No |
What this study does not show
- 1.Whether intermittent dutasteride reduces sexual side effects. The study was too small to detect this.
- 2.Whether results would hold in a larger confirmatory trial.
- 3.How intermittent dutasteride compares to daily dutasteride 0.5mg.
- 4.Long-term outcomes beyond 24 weeks.
Limitations
- 1.Only 60 participants — a very small pilot study
- 2.Single-centre study conducted in Thailand
- 3.Participants were not blinded to treatment allocation
- 4.Dutasteride is not FDA-approved for hair loss
- 5.Pilot study by design — conclusions are preliminary
Who funded it
Funded by the Faculty of Medicine, Srinakharinwirot University. No commercial conflicts of interest declared.
Used in these articles
Links added as fact-checks and articles citing this study are published.