Quick answer: Yes. Saw palmetto inhibits both types of 5α-reductase, the enzyme that converts testosterone into DHT. In people, a systematic review of seven studies found improved hair density in 83.3% of patients and a 27% gain in total hair count, with no serious side effects.
What is saw palmetto?
Saw palmetto (Serenoa repens) is a small palm native to the southeastern United States. Extracts of its berries have been used for decades for prostate health, which is where its effect on DHT was first studied. Today it's the most-researched botanical for pattern hair loss.
How saw palmetto blocks DHT
Your body makes DHT when 5α-reductase acts on testosterone. There are two main types of the enzyme: type 1 in skin and oil glands, type 2 in hair follicles and the prostate. Finasteride blocks type 2. Saw palmetto extract has been shown to inhibit both (Wessagowit 2016). Less DHT at the follicle means less of the gradual shrinking that causes thinning at the temples and crown.
It doesn't lower testosterone. It slows the conversion into DHT.
What the studies found
| Study | Design | Result |
|---|---|---|
| Evron 2020 | Systematic review: 5 randomized trials, 2 cohort studies, oral and topical | Improved hair density in 83.3% of patients; 27% gain in total hair count; 60% improvement in overall hair quality; well tolerated |
| Rossi 2012 | 100 men, 320 mg oral saw palmetto vs finasteride 1 mg, 2 years | 38% improved on saw palmetto, 68% on finasteride; saw palmetto worked mainly at the crown |
| Wessagowit 2016 | 50 men, topical saw palmetto lotion and shampoo, 24 weeks | Average and terminal hair counts increased at weeks 12 and 24; limited side effects |
Oral or topical saw palmetto?
Oral saw palmetto (usually 320 mg a day in studies) circulates through the whole body. Topical saw palmetto goes on the scalp, where pattern hair loss happens. The Wessagowit authors concluded that topical saw palmetto could be an alternative for men who don't want, or can't tolerate, the side effects of standard medications. A scalp oil also lets you combine it with other actives in one step.
Does saw palmetto have side effects?
Across the studies in the 2020 review, saw palmetto was well tolerated and not linked to serious adverse events. Topical products can irritate sensitive skin, so patch test on your inner arm first. If you take prescription medication, check with your pharmacist before adding any supplement.
How long does saw palmetto take to work?
Plan on 8 to 16 weeks of daily use before you assess anything, and six months for a fair verdict. The topical study saw hair counts rise by week 12. Take a baseline photo on day one, in the same light you'll use for later comparisons.
Saw palmetto works better with company
Pumpkin seed oil is the other natural DHT blocker with strong human data, and rosemary oil supports the scalp through a different pathway. DHT Defense Hair Oil combines all three with bhringraj in a light grapeseed base, so you get the full routine in one bottle, applied straight to the root.
Frequently asked questions
Does saw palmetto really block DHT?
Yes. Saw palmetto extract inhibits both types of 5α-reductase, the enzyme that converts testosterone to DHT.
Can saw palmetto regrow hair?
Studies report increased hair counts and density, particularly at the crown and in early to moderate hair loss.
Is saw palmetto better than finasteride?
No. Finasteride is stronger. Saw palmetto is a gentler, non-prescription option for men who prefer to avoid finasteride or are in the early stages.
Does saw palmetto affect testosterone?
It slows the conversion of testosterone into DHT. It doesn't stop your body from producing testosterone.
Is topical saw palmetto effective?
A 24-week study of topical saw palmetto found higher hair counts at weeks 12 and 24. Topical use keeps the focus on the scalp.
Related reading
- Natural DHT blockers for hair loss: what the research shows
- Finasteride alternatives compared
- DHT, Explained: the full guide
References
- Evron E, Juhasz M, Babadjouni A, Mesinkovska NA. Natural hair supplement: friend or foe? Saw palmetto, a systematic review in alopecia. Skin Appendage Disord. 2020;6(6):329-337. PMID 33313047
- Rossi A, et al. Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. Int J Immunopathol Pharmacol. 2012;25(4):1167-73. PMID 23298508
- Wessagowit V, et al. Treatment of male androgenetic alopecia with topical products containing Serenoa repens extract. Australas J Dermatol. 2016;57(3):e76-82. PMID 26010505