Dutasteride (Avodart)
Dual 5α-reductase inhibitor (type-I + type-II). FDA-approved (2001 GSK) for BPH. In AAS: ~90% scalp DHT + acne reduction. Long t1/2 ~5 weeks – washout ~6 months. Higher PFS risk vs finasteride.
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WHAT IS DUTASTERIDE (AVODART)?
Detailed overview
Dutasteride (Avodart) is a dual 5α-reductase inhibitor that blocks both the type-I and type-II isoforms, giving a significantly broader DHT suppression spectrum than finasteride. Developed by GSK and FDA-approved in 2001 for benign prostatic hyperplasia (BPH) (Avodart 0.5 mg). The Olsen 2006 (PMID 16782546) randomized head-to-head trial documented that dutasteride at 0.5 mg/day achieves **~90% scalp DHT** + ~95% prostate DHT suppression – vs finasteride 1 mg/day ~70% scalp DHT. This higher suppression + type-I (skin/sebum) inhibition provides a bonus **acne improvement** secondary effect in AAS users (reducing acne tendency from testosterone elevation). Off-label AGA use is widespread (Korea + Japan: AGA Rx; US/EU: off-label). Long half-life ~5 weeks → washout ~6 months (finasteride 2 weeks vs dutasteride 6 months – significant sexual/decision implication in fertility planning). Tier 4 – second-line after finasteride, or first-line if acne emphasis. Higher PFS risk than finasteride (Trost 2017 PMID 28267184).
Mechanism
Dual 5α-reductase inhibitor (type-I + type-II), ~90% scalp DHT suppression at 0.5 mg/day
Dosing (AAS hair-loss + acne)
0.5 mg/day continuous or every other day (cost-saving)
Half-life
~5 weeks (very long, steady-state ~6 months, washout ~6 months)
Onset
DHT reduction measurable 1 week, hair stabilization 3-6 months
Legal status
FDA + EMA Rx (BPH), HU + PL approved, off-label AGA US/EU, WADA allowed
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 7
- Sexual side effects: reduced libido, erectile dysfunction, decreased ejaculate volume, and less commonly orgasmic dysfunction (more frequent and more persistent than with finasteride).
- Persistent post-5AR-inhibitor syndrome (PFS-like): sexual, neurological and mood symptoms that may persist after discontinuation; symptoms resolve more slowly than with finasteride due to the long half-life.
- Mood disturbances: depression, anxiety and rarely suicidal ideation; history of depression increases the risk (documented by Trost 2017).
- Gynecomastia and breast tenderness: breast swelling or tenderness due to the shifted DHT/estrogen ratio (uncommon, listed in the FDA label).
- Reduced sperm count, motility and ejaculate volume with transient impaired fertility; due to the ~6-month washout, it must be stopped well ahead of planning conception.
- Lowers serum PSA by roughly 50%, which can mask a prostate cancer screening signal; PSA results on a 5AR inhibitor must be interpreted as doubled.
- Allergic reactions: rash, pruritus, urticaria, localized edema and rarely angioedema may occur.
Contraindications · 7
- Pregnant or potentially pregnant women must not handle leaking/broken capsules or take it (Pregnancy Category X): DHT suppression disrupts male fetal genital development.
- Active plans to conceive: due to the ~6-month washout it must be stopped well before conception; the drug is excreted into semen.
- Hypersensitivity to dutasteride or other 5-alpha-reductase inhibitors.
- Age under 18 and women (especially those of childbearing potential): not an indicated population.
- Active depression or suicide risk, or a history of PFS-like symptoms: increased risk of mood and persistent side effects.
- Severe hepatic impairment: metabolism is predominantly hepatic, caution is required (renal excretion is minimal).
- Blood donation prohibition: must not donate blood during treatment and for at least 6 months after the last dose, to avoid exposure of a pregnant recipient.
Related Performance Compounds
Same therapeutic category
Studies
Related research and clinical findings
Long-term efficacy and safety of dutasteride 0.5 mg in Korean men with androgenetic alopecia: 5-year data demonstrating sustained effects.
Choi S, Kwon SH, Sim WY
Evaluation of the therapeutic effects of AGA drugs by measuring finasteride, dutasteride, and dihydrotestosterone in hair.
Hobo Y, Nishikawa J, Taniguchi Asai N
Post-Finasteride Syndrome: Survey of Dermatologists From the Spanish Hair and Nail Disorders Group.
Moreno-Arrones OM, Saceda-Corralo D, Gómez-Cano JL
Updates in Treatment for Androgenetic Alopecia.
Shin JW, Huh CH
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The information here is for educational and scientific purposes only. Performance-enhancing compounds (AAS, prohormones, stimulants, doping agents) are illegal without prescription in Hungary and most of the EU, and carry serious health and legal risks. WADA bans them in competitive sport. This is NOT a usage guide, and we do not encourage any illegal use. If you do use them, medical supervision and regular bloodwork are ESSENTIAL. Severe endocrine, cardiovascular, hepatic and psychiatric side effects are possible.