Dutasteride

Dutasteride inhibits type-I and type-II 5-alpha-reductase. Two randomized oral trials support male androgenetic-alopecia outcomes, but US Avodart approval is for BPH, not hair loss.

tier A · skin · 917 men in the active-comparator alopecia trial

verdict

Oral dutasteride 0.5 mg improved measured hair outcomes in two six-month male alopecia trials and beat finasteride on specified 24-week endpoints in one. It is not FDA approved for hair loss, and the results do not transfer to topical or injected products.

the core tension

Dutasteride has meaningful randomized oral hair evidence, but dual DHT blockade is systemic, not a scalp-only effect, and the approximately five-week steady-state half-life makes exposure slow to reverse. The benefit has to be weighed against the controlled-trial and label safety record, while persistence and postmarketing mood statements retain their qualifiers. US approval and the mature safety file still belong to BPH, and neither one validates topical or injected hair products.

what it is

Dutasteride is a dual type-I and type-II 5-alpha-reductase inhibitor. Avodart is a 0.5-mg oral soft-gelatin capsule; compounded topical products and injected or mesotherapy products are separate evidence records.

what it does

It reduces conversion of testosterone to DHT through both 5-alpha-reductase isoenzymes in a systemic, non-hair-selective intervention. Broader enzyme inhibition and greater DHT suppression do not alone prove better benefit or safety in every hair-loss population.

origin

FDA-approved Avodart treats symptomatic benign prostatic hyperplasia in men with an enlarged prostate. Hair loss is not a US labeled indication, even though randomized oral alopecia trials exist.

does it work

A 917-man trial found dose-related hair responses, with 0.5 mg dutasteride superior to finasteride 1 mg on specified hair-count, width, and frontal-photography endpoints at 24 weeks. A 153-man placebo-controlled trial reported a smaller absolute hair-count gain over six months.

key facts

• molecular formula: C27H30F6N2O2
• molecular weight: 528.5307 g/mol
• amino acids: n/a (steroidal small molecule, not a peptide)
• half-life: about 5 weeks at steady state after oral Avodart exposure
• type: dual type-I and type-II 5-alpha-reductase inhibitor
• CAS: 164656-23-9
• 917 men in the active-comparator alopecia trial
• 153 men in the placebo-controlled alopecia trial
• about 5 weeks oral terminal half-life at steady state

frequently asked questions

Is dutasteride FDA approved for hair loss?

No. Avodart is approved for BPH. The alopecia evidence is randomized human evidence for an off-label oral use.

Did it beat finasteride?

Oral dutasteride 0.5 mg beat oral finasteride 1 mg on specified endpoints at 24 weeks in one 917-man trial. That does not prove permanent or universal superiority.

What is the oral half-life?

The current Avodart label reports about five weeks at steady state, with serum concentrations detectable for up to four to six months after stopping. That is oral-capsule PK.

Does oral PK apply to topical or injected dutasteride?

No. Those routes and formulations do not inherit Avodart exposure, approval, or the oral alopecia trial results.

Why does the label discuss blood donation?

Because of long persistence and fetal risk, treated patients should not donate blood until at least six months after their last dose.

What can systemic DHT blocking with dutasteride affect?

Blocking DHT is not scalp-only. In pooled BPH trials during months 0 to 6, impotence was 4.7% with Avodart versus 1.7% with placebo, decreased libido 3.0% versus 1.4%, ejaculation disorders 1.4% versus 0.5%, and breast disorders 0.5% versus 0.2%. Those BPH rates are not a hair-loss risk estimate. The label says sexual adverse reactions may persist after discontinuation, but dutasteride's role in that persistence is unknown. It also reports mean reductions in sperm count, semen volume, and sperm motility, with unknown individual fertility significance, plus PSA, prostate-cancer, pregnancy, blood-donation, and long-persistence warnings.

related peptides

• Finasteride: The 917-man trial cited on this page establishes finasteride only as dutasteride's active oral comparator; it does not establish finasteride's FDA approval.
• Minoxidil: The dutasteride evidence cited on this page does not establish minoxidil's route, approval, PK, or outcomes.

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.