Dutasteride vs Finasteride: side-by-side comparison
Avodart · Dut · Duta
A dual 5-alpha reductase inhibitor that blocks both Type I and Type II isoenzymes, reducing serum DHT by roughly 90-94% at steady state (FDA trial median; some sources cite up to ~98%), versus ~70% with finasteride. More potent than finasteride for hair loss prevention but with a very long half-life of ~5 weeks. Clinically superior to finasteride for hair count and growth in head-to-head trials. Same caveats apply: only works with testosterone-based compounds, not DHT derivatives, and worsens nandrolone-related hair loss.
Propecia · Proscar · Fin
A 5-alpha reductase inhibitor that blocks the conversion of testosterone to DHT, reducing serum DHT by 65-70%. Used during testosterone cycles to prevent DHT-related hair loss. CRITICAL: Only works with testosterone-based compounds. Does NOT work with DHT derivatives (Masteron, Winstrol, Anavar). Makes hair loss WORSE with nandrolone compounds.
1 / 10 natty scale / 1
Same lane
Both sit in the same class and are run for health. This is a like-for-like comparison: read the gaps as real trade-offs.
The tape
Core ratings
The same three rulers every entry on the site is scored with, read head to head.
Natty scale
1 natural · 10 heavy
Effectiveness
Documented effect · of 5Δ0.5
Side-effect severity
Documented burden · of 5
Cost side
Body-load fingerprint
Where each one actually lands its strain, on the calculator's thirteen channels. Tap a row for what it means and which labs track it.
Hormonal
Systemic
Bars show strain at each one's typical protocol, not your dose. ≈ marks values inferred from side-effect data or category rather than hand-graded. For your numbers, run the calculator.
Logistics
The vitals
Benefit side
What each is for
Shared goals carry both dots; a goal with one dot belongs to that side alone.
Run for
Documented upside
- Reduces serum DHT by roughly 90-94% (FDA trial median; up to ~98% in some sources), vs ~70% with finasteride
- Inhibits both Type I and Type II 5-alpha reductase
- Commonly cited as ~3x more potent than finasteride at Type II inhibition, ~100x at Type I
- Clinically superior hair count results vs finasteride in a 917-man phase III trial (P=.003)
- Can be dosed 2-3x weekly due to long half-life
Run for
Documented upside
- Reduces serum DHT by 65-70%
- FDA Propecia 5-year trials: 90% of men had no further hair loss (48% regrowth, 42% no change)
- May increase circulating testosterone by ~15% (still within physiologic range)
- Does NOT impair muscle gains from testosterone (12-month RCT confirmed)
- 25% reduction in prostate cancer risk (PCPT trial)
The downsides
Side effects, aligned
Each entry's documented side effects, sorted onto the same body systems so the gaps and the overlaps are visible. Tap any effect for the detail.
None documented
The exit
Hormonal fallout & recovery
What each does to your own hormone axis while on, and what leaving it costs.
Dutasteride
Does not affect HPT axis directly. No PCT required. Very long half-life means effects persist months after stopping.
Finasteride
Does not affect HPT axis directly. No PCT required. Can be used long-term. May slightly increase testosterone by blocking DHT conversion.
Read-out
How they separate
- 01
Enhancement
They land at almost the same point on the natty scale (1/10 vs 1/10): a similar distance beyond natural.
- 02
Body load
The widest gap at typical protocols is shutdown depth (Dutasteride 3.2/10 vs 0/10).
- 03
Coming off
Neither requires PCT: both leave the natural testosterone axis running.
- 04
Logistics
typical runs are 24-52 weeks vs 12-52 weeks.
Generated from each entry's data file. Descriptive, not a recommendation; nothing here is medical advice.