Dutasteride vs Finasteride
FDA Approved vs FDA Approved
avoid Researched · 95% Both are 5-alpha reductase inhibitors. Dutasteride already blocks both Type I and Type II isoforms, making the addition of finasteride entirely redundant. Combining them provides no additional benefit and unnecessarily increases the risk of side effects from excessive DHT suppression.
Molecular Data
Dutasteride Finasteride
Weight 528.53 Da 372.54 Da
Half-life ~5 weeks (extremely long; active metabolite accumulation over months) 6-8 hours (DHT suppression persists ~24 hours)
Type Synthetic 4-azasteroid compound (dual 5-alpha reductase inhibitor) Synthetic 4-azasteroid compound
Key Benefits
Dutasteride
01 Inhibits both Type I and Type II 5-alpha reductase for more complete DHT suppression
02 Reduces serum DHT by approximately 90%, compared to 70% with finasteride
03 Head-to-head trials show superior hair count improvements over finasteride at 12 and 24 weeks
04 FDA-approved for BPH with well-established long-term safety data
05 Extremely long half-life allows for flexible dosing schedules (daily or 3x per week)
06 Convenient once-daily oral dosing with no injections required
07 Can be combined with minoxidil for enhanced hair loss treatment
Finasteride
01 Reduces scalp DHT by approximately 66% at 1mg daily
02 Slows or stops hair loss progression in roughly 90% of men
03 Produces visible hair regrowth in approximately 48% of men within 1-2 years
04 FDA-approved with over 25 years of clinical use and long-term safety data
05 Convenient once-daily oral dosing with no injections required
06 Well-characterized side effect profile with low incidence of adverse events
07 Can be combined with minoxidil for enhanced efficacy
Side Effects
Dutasteride
Decreased libido (reported in 3-5% of men; somewhat higher incidence than finasteride due to greater DHT suppression)
Erectile dysfunction (reported in 3-5%; more frequently reported than with finasteride)
Decreased ejaculate volume (reported in 1-2%)
Gynecomastia or breast tenderness (reported in approximately 1-2%)
Finasteride
Decreased libido (reported in 1.8% of men in clinical trials vs 1.3% placebo)
Erectile dysfunction (reported in 1.3% vs 0.7% placebo)
Decreased ejaculate volume (reported in 0.8% vs 0.4% placebo)
Contraindications
Women who are pregnant or may become pregnant (dutasteride is teratogenic and can cause abnormalities of external genitalia in a male fetus; even handling damaged capsules poses a risk due to skin absorption)
Women who are breastfeeding
Known hypersensitivity to dutasteride, other 5-alpha reductase inhibitors, or any component of the formulation
Severe hepatic impairment (dutasteride is extensively metabolized by the liver via CYP3A4)
Pediatric patients (not indicated for use in children)
Co-administration with strong CYP3A4 inhibitors (e.g., ritonavir, ketoconazole) may significantly increase dutasteride levels
Women who are pregnant or may become pregnant (finasteride is teratogenic and can cause abnormalities of external genitalia in a male fetus; even handling crushed tablets poses a risk)
Women who are breastfeeding
Known hypersensitivity to finasteride or any component of the formulation
Severe hepatic impairment (finasteride is metabolized by the liver)
Pediatric patients (not indicated for use in children)
Research Evidence
Dutasteride Finasteride
Status FDA Approved FDA Approved
References 5 studies 5 studies
FDA Approved Yes Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.