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At a Glance
- Evidence A 2020 systematic review found modest benefits in 5 randomized trials and 2 cohort studies, but said high-quality data are lacking1.
- Vs finasteride In a 2-year open-label study of 100 men, 38% improved on saw palmetto 320 mg vs 68% on finasteride2.
- Newer trials Two placebo-controlled trials of branded extracts found less shedding and more hair after 16 weeks to 6 months, in men and women45.
- Safety Generally well tolerated19. Avoid it in pregnancy and in children91011.
- Top pick NOW Saw Palmetto Extract 320 mg – 320 mg of extract standardized to 85–95% fatty acids, the dose used in the finasteride comparison, from our guide to the best pumpkin seed oil with saw palmetto supplements.
The Short Answer: Saw palmetto may slow male- and female-pattern hair loss a little, but it’s weaker than finasteride. In the longest study, 38% of men improved on saw palmetto after 2 years, compared with 68% on finasteride2. Newer placebo-controlled trials are encouraging, but they’re small, short and tested specific branded extracts45.
On this page
If you want to try it, give it 4–6 months and use a standardized extract. Compare products in our guide to the best pumpkin seed oil with saw palmetto supplements.
How Saw Palmetto Is Thought to Help Hair
Pattern hair loss is linked to DHT, a hormone made from testosterone by the enzyme 5-alpha reductase. Saw palmetto is thought to block this enzyme, like a weaker version of finasteride1. In one 16-week trial, saw palmetto capsules lowered blood DHT compared with placebo4. For the full explanation, see how saw palmetto blocks DHT and our comparison of natural vs prescription DHT blockers.
Saw Palmetto Hair Loss Studies
| Study | Who and what | Result | Limits |
|---|---|---|---|
| Finasteride comparison 20122 | 100 men; saw palmetto 320 mg/day vs finasteride 1 mg/day; 2 years | 38% improved vs 68% on finasteride | Open label; no placebo |
| Pilot trial 20023 | Men 23–64; saw palmetto extract + beta-sitosterol vs placebo | 6 of 10 on the active formula rated improved | Very small; combination product |
| VISPO trial 20234 | 80 men and women; 400 mg capsule or 20% topical vs placebo; 16 weeks | Hair fall down 29% (oral) and 22% (topical); density up 5.17% and 7.61% | Short; branded extract; growth-phase ratio unchanged |
| SEREVELLE trial 2025–202656 | 60 men and women with thinning hair; one daily dose vs placebo; 6 months | Terminal hair count +18.6 vs −10.1 | Small; branded extract |
| Topical study 20167 | 50 men; topical saw palmetto products; 24 weeks | Hair counts rose vs baseline | No placebo group |
Oral Saw Palmetto vs Finasteride
In the only long-term comparison, 100 men with mild to moderate hair loss took saw palmetto 320 mg or finasteride 1 mg a day for 2 years. Hair growth improved in 38% on saw palmetto and 68% on finasteride. The authors observed that finasteride worked on both the front and the crown, while saw palmetto worked mainly on the crown2. The study wasn’t blinded. See our full guide to saw palmetto vs finasteride.
Newer Placebo-Controlled Trials
A 2023 trial gave 80 adults with mild to moderate pattern hair loss a 400 mg capsule of standardized saw palmetto oil, a topical version, or placebo for 16 weeks. Hair fall dropped by up to 29% with capsules, density rose 5.17%, and blood DHT fell compared with placebo. The share of hairs in the growing phase didn’t change4.
A 6-month trial of a different branded extract found terminal hair counts rose by 18.6 on average, while they fell by 10.1 on placebo. Benefits were seen in both men and women after menopause, and no treatment-related side effects were reported5. A 2026 network meta-analysis of 19 supplement trials also found a saw palmetto extract improved doctors’ blinded hair ratings compared with placebo8.
These trials tested specific branded extracts, so the results may not apply to other products.
Our Top Saw Palmetto Pick
NOW Saw Palmetto Extract 320 mg
320 mg extract85–95% fatty acids1 softgel a day
NOW gives 320 mg of saw palmetto extract standardized to 85–95% fatty acids, the daily dose used in the 2-year hair loss comparison with finasteride, in one softgel with a pumpkin seed oil base. It’s the best standardized extract in our guide to the best pumpkin seed oil with saw palmetto supplements. It hasn’t been tested in its own hair trial.
Saw Palmetto for Hair Loss in Women
Women were included in two of the newer trials. In the 6-month trial, half the participants were women6, and women after menopause had more terminal hairs and higher hair density than on placebo5. The 16-week trial also enrolled men and women4.
Saw palmetto isn’t safe for everyone, though. NCCIH says it may be unsafe during pregnancy or while breastfeeding9. Women who are pregnant, trying to conceive or taking hormonal medicines should check with a doctor first.
Topical vs Oral Saw Palmetto
In the 16-week trial, the topical version raised hair density slightly more (7.61% vs 5.17%), but only the capsules lowered blood DHT4. A 24-week study of topical products in 50 men found hair counts rose, but it had no placebo group7. Oral saw palmetto has the longer track record12.
Saw Palmetto Dosage for Hair Loss
- 320 mg a day: used in the 2-year finasteride comparison2
- 400 mg capsule once a day: used in the 16-week trial of a standardized saw palmetto oil4
- One daily dose of a branded extract in the 6-month trial5
The 2020 review found hair studies used 100–320 mg1. No hair trial has compared doses. Choose a product that lists the extract amount and fatty acid content, and follow the label.
How Long Does Saw Palmetto Take to Work for Hair?
| Time point | What trials found |
|---|---|
| 90 days | More terminal hairs than placebo in one trial6 |
| 16 weeks | Less hair fall and higher density4 |
| 6 months | Larger gains in hair count and density5 |
| 2 years | 38% of men improved2 |
Plan on 4–6 months of daily use before judging. Take photos in the same light each month to track changes. For prostate use, see how long saw palmetto takes to work.
Side Effects and Safety
- Common: Saw palmetto was well tolerated in hair studies, with no serious side effects1. NCCIH lists mild digestive symptoms, dizziness and headache9.
- Children: Two case reports describe hot flashes in girls aged 10 and 11 taking saw palmetto for hair problems; both had their first period about 4 months after starting it1011. Don’t give it to children.
- Pregnancy and breastfeeding: May be unsafe9.
- Surgery and other risks: See our full guide to saw palmetto side effects.
- See a doctor first if hair loss is sudden or patchy, since it can have other causes.
Final Verdict
Saw palmetto is a low-risk option that may slow pattern hair loss a little, mainly at the crown. It’s clearly weaker than finasteride2, and the most positive trials are small, short and tested branded extracts45. It may suit people who can’t or don’t want to use finasteride, as long as their expectations are modest.
If you want to try it, use the studied 320 mg dose, such as NOW Saw Palmetto Extract 320 mg, and give it at least 4–6 months. For a pumpkin seed oil option, see pumpkin seed oil for hair loss, and for the broader picture, saw palmetto benefits.
Important: This guide is for general information and isn’t medical advice. See a doctor or dermatologist about hair loss, and don’t use saw palmetto if you’re pregnant or breastfeeding.
Frequently Asked Questions
Does saw palmetto work for hair loss?
How much saw palmetto should I take for hair loss?
How long does saw palmetto take to work for hair?
Does saw palmetto regrow hair?
Does saw palmetto work for women’s hair loss?
Is saw palmetto better than finasteride?
No. Finasteride helped 68% of men vs 38% on saw palmetto in a 2-year study2.
Sources & History
References
- Natural Hair Supplement: Friend or Foe? Saw Palmetto, a Systematic Review in Alopecia — Skin Appendage Disorders, 2020
- Comparative Effectiveness of Finasteride vs Serenoa repens in Male Androgenetic Alopecia: A Two-Year Study — International Journal of Immunopathology and Pharmacology, 2012
- A Randomized, Double-Blind, Placebo-Controlled Trial to Determine the Effectiveness of Botanically Derived Inhibitors of 5-Alpha-Reductase in the Treatment of Androgenetic Alopecia — Journal of Alternative and Complementary Medicine, 2002
- Oral and Topical Administration of a Standardized Saw Palmetto Oil Reduces Hair Fall and Improves the Hair Growth in Androgenetic Alopecia Subjects: A 16-Week Randomized, Placebo-Controlled Study — Clinical, Cosmetic and Investigational Dermatology, 2023
- The Safety and Efficacy of a Novel Saw Palmetto (Serenoa repens) Extract for Promoting Hair Growth in Adults With Self-Perceived Thinning Hair: 180-Day Results — Journal of Cosmetic Dermatology, 2026
- The Safety and Efficacy of a Proprietary Bioactive Fatty Acids Extract From Saw Palmetto (Serenoa repens) for Promoting Hair Growth and Reducing Hair Loss in Adults With Self-Perceived Thinning Hair: 90-Day Results — Journal of Cosmetic Dermatology, 2025
- Treatment of Male Androgenetic Alopecia With Topical Products Containing Serenoa repens Extract — Australasian Journal of Dermatology, 2016
- Effects of Dietary Supplements on Androgenetic Alopecia: A Systematic Review and Network Meta-Analysis — Frontiers in Nutrition, 2026
- Saw Palmetto: Usefulness and Safety — National Center for Complementary and Integrative Health
- Hot Flashes in a Young Girl: A Wake-Up Call Concerning Serenoa repens Use in Children — Pediatrics, 2012
- Serenoa repens as an Endocrine Disruptor in a 10-Year-Old Young Girl: A New Case Report — Pharmacology, 2015
Update history
- Rewritten with a study table and timeline table, added the 180-day results of the 2025 trial and a 2026 network meta-analysis, noted that the finasteride comparison was open label and that saw palmetto worked mainly at the crown, and replaced a news source with original studies.
