Dutasteride
What is dutasteride?
Dutasteride is a prescription drug that blocks the enzymes that turn testosterone into DHT, the hormone that shrinks hair follicles in pattern hair loss. It is approved for an enlarged prostate, and for hair loss in South Korea and Japan. Some people apply it to the scalp or have it injected there to limit whole-body effects.
Listed here because well-known people have tried it on themselves. Trying something is not recommending it; each entry says whether the person tells others to do it.
Who has tried it
Tried by 1 person we can source: 1 kept.
Kept
Bryan JohnsonEntrepreneur, founder of BlueprintBlueprint (Bryan Johnson)
Dates not stated · Does not recommend it to others
Used a custom topical scalp formula with 0.25% dutasteride, avoiding oral finasteride; when twice-daily use pushed his blood DHT too low, he cut back to once a day.
“I’m back at 1x daily and will retest my blood in 90 days.”
Bryan Johnson, How I Reversed My Hair Loss (October 2024) · Status checked October 18, 2024 · Suggest a correction
What the evidence shows
Oral dutasteride works for male pattern hair loss. In a trial of 917 men, 0.5 mg a day grew more hair than finasteride 1 mg or placebo at 24 weeks [1], and a network meta-analysis ranked it first for total hair count [2].
Topical and injected forms, which aim to avoid side effects, have weaker evidence. A review found that scalp injections and microneedling with dutasteride show some benefit but lack standard protocols and large trials [3], and a study of 541 patients receiving scalp injections had no control group [4].
Dutasteride is approved for an enlarged prostate everywhere and for hair loss only in some countries. Topical formulas are compounded and untested in large trials.
Safety
- Dutasteride is approved for an enlarged prostate, and for male hair loss in South Korea and Japan. Topical and compounded use is off-label and unstandardized.
- Possible side effects include lower libido, erectile problems, lower ejaculate volume and breast tenderness; mood changes are reported.
- Women who are or may become pregnant must not take or handle it, because it can harm a male fetus. Men taking it should not donate blood until 6 months after the last dose.
- It roughly halves PSA, which matters for prostate cancer screening. Applied to the scalp, it can still lower blood DHT.
Common questions
Does Bryan Johnson take finasteride?
No. In October 2024 he wrote that he had avoided oral finasteride and its side effects. His custom topical formula instead contained 0.25% dutasteride, along with minoxidil and other ingredients.
Does Bryan Johnson use dutasteride now?
His October 2024 post lists dutasteride in his scalp formula. His 2026 routine describes the formula as 5% minoxidil with a few other ingredients without naming them, so whether it still contains dutasteride is not confirmed.
Is dutasteride better than finasteride for hair loss?
Taken by mouth, yes in trials: 0.5 mg a day grew more hair than finasteride 1 mg at 24 weeks [1]. Side effects are similar in kind.
Sources
- 1.Gubelin Harcha W, Barboza Martínez J, Tsai TF, et al. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia. J Am Acad Dermatol, 2014. doi:10.1016/j.jaad.2013.10.049
- 2.Gupta AK, Venkataraman M, Talukder M, et al. Relative Efficacy of Minoxidil and the 5-α Reductase Inhibitors in Androgenetic Alopecia Treatment of Male Patients: A Network Meta-analysis. JAMA Dermatol, 2022. doi:10.1001/jamadermatol.2021.5743
- 3.Ding Y, Wang C, Bi L, et al. Dutasteride for the Treatment of Androgenetic Alopecia: An Updated Review. Dermatology, 2024. doi:10.1159/000541395
- 4.Saceda-Corralo D, Moustafa F, Moreno-Arrones Ó, et al. Mesotherapy With Dutasteride for Androgenetic Alopecia: A Retrospective Study in Real Clinical Practice. J Drugs Dermatol, 2022. PubMed 35816059