DHT Blockers Explained: How Finasteride, Dutasteride, and Saw Palmetto Compare

Three ways to block the hormone that kills your hair follicles. One has decades of FDA data. One is stronger but off-label. One is natural but barely works.

DHT (dihydrotestosterone) is the primary hormonal driver of male pattern baldness. It binds to androgen receptors in genetically susceptible hair follicles, causing them to miniaturize — producing progressively thinner, shorter hairs until the follicle eventually stops producing visible hair altogether.

Blocking DHT production is the most direct way to stop this process. There are three main approaches, and they are not created equal.

The Three DHT Blockers

Finasteride (Propecia) — The Gold Standard

Finasteride inhibits Type II 5-alpha reductase, the enzyme primarily responsible for converting testosterone to DHT in the scalp. At the standard 1mg daily dose, it reduces serum DHT levels by approximately 70%. It was FDA-approved for male pattern hair loss in 1997 and remains the most prescribed DHT blocker worldwide.

Efficacy: 83% of men maintain hair count, 66% experience regrowth in clinical trials over 2 years. These numbers hold through 5+ year follow-up studies.

Dutasteride (Avodart) — Stronger, Off-Label

Dutasteride inhibits both Type I and Type II 5-alpha reductase, reducing DHT by approximately 90% — significantly more than finasteride. It is FDA-approved for benign prostatic hyperplasia (BPH) at 0.5mg daily, but used off-label for hair loss at the same dose.

Efficacy: Head-to-head studies show dutasteride produces superior hair count improvements compared to finasteride. A 2006 randomized trial in the Journal of the American Academy of Dermatology found dutasteride 0.5mg significantly outperformed finasteride 1mg on multiple hair count metrics.

The catch: More potent DHT suppression means a slightly higher rate of sexual side effects. The drug also has a very long half-life (5 weeks vs. 6 hours for finasteride), meaning side effects take longer to resolve if you stop. Most dermatologists recommend trying finasteride first and moving to dutasteride only if the response is insufficient.

Saw Palmetto — The Natural Alternative

Saw palmetto is a plant extract that weakly inhibits 5-alpha reductase. It's widely marketed as a "natural finasteride" in the supplement industry. The appeal is obvious — a natural compound without prescription side effects that still blocks DHT.

Efficacy: A handful of small studies suggest mild benefit, but the evidence is nowhere near the quality or magnitude of finasteride or dutasteride data. A 2020 systematic review in the Journal of Alternative and Complementary Medicine found that saw palmetto showed "some promise" but concluded the evidence was "insufficient to recommend as a standalone treatment." Translation: it might help a little, but not enough to rely on.

Paid link

Head-to-Head Comparison

So Which Should You Take?

Start with finasteride. It has the best risk-benefit ratio: strong efficacy, well-characterized side effect profile, short half-life (so it clears your system quickly if you stop), and decades of safety data. It is the recommended first-line DHT blocker for hair loss by every major dermatological society.

Consider dutasteride if you've been on finasteride for 12+ months and your response is insufficient. The step-up in DHT suppression can push non-responders into responder territory. Discuss with your provider — this should be a deliberate medical decision, not a self-directed switch.

Saw palmetto is reasonable as a complement to pharmaceutical treatment, or as a starting point for men who are genuinely unwilling to consider prescription medication. But be honest with yourself about expectations — it's not a substitute for finasteride.

Paid link

Paid link