Research review
Does saw palmetto raise or lower testosterone?
The evidence doesn't support saw palmetto changing testosterone levels in either direction. The largest trial to measure a related outcome (sexual function) found no difference from placebo. Two small studies found hormone shifts, but both tested saw palmetto only as part of a multi-ingredient blend, so neither shows what saw palmetto alone does.
The evidence doesn't support saw palmetto raising or lowering testosterone in a person. The largest trial to measure a related outcome found no difference from placebo. Two small studies did find hormone shifts, but both tested saw palmetto only as part of a multi-ingredient blend, so neither shows what saw palmetto contributed on its own.
What the evidence doesn't support
It doesn't support saw palmetto, taken alone at any dose sold today, as a way to raise testosterone, lower testosterone, increase libido, or change sexual function. It doesn't support the idea that saw palmetto's laboratory-demonstrated ability to block an enzyme involved in testosterone conversion translates into a measured hormone change in a person taking a capsule.
What the trials found
The most directly relevant human data comes from the CAMUS trial, which followed 369 men for 72 weeks while escalating the saw palmetto dose up to three times standard (960 mg/day) and measured sexual function as one of ten secondary outcomes. It found no difference between saw palmetto and placebo on that measure, at any dose tested.
Two smaller trials found hormone changes, but neither tested saw palmetto by itself. A crossover trial in 20 sedentary men tested a blend of saw palmetto and astaxanthin at 800 or 1,200 mg/day against a placebo. At the higher dose, DHT and estradiol dropped significantly compared with placebo, and testosterone rose 38% compared with placebo — a result the study reports did not reach statistical significance. Because the product combined two ingredients, the trial can't say which one, or what combination of both, produced those changes. A second trial tested a six-ingredient blend — 300 mg androstenedione, 150 mg DHEA, 540 mg saw palmetto, 300 mg indole-3-carbinol, 625 mg chrysin and 750 mg Tribulus terrestris daily — in 55 men over 28 days, and found increases in free testosterone (38%), DHT (71%) and estradiol (103%) versus baseline. Androstenedione is itself a direct precursor the body converts into testosterone, so a testosterone increase in a blend built around it isn't evidence that saw palmetto did anything; the study's own authors concluded the herbal ingredients, including saw palmetto, failed to prevent the androstenedione from converting into DHT and estradiol as the formula intended.
The mechanistic case for an effect comes from a laboratory study, not a person: one specific saw palmetto extract blocked 5-alpha-reductase, the enzyme that converts testosterone into DHT, in cultured prostate cells. A 2026 review of botanicals and hormones singled saw palmetto out for exactly this pattern — a plausible enzyme-blocking mechanism in a dish that hasn't translated into a positive result in human trials, unlike a small number of other herbs with modest human evidence for raising testosterone.
Questions people ask
Does saw palmetto increase testosterone?
No trial of saw palmetto alone has shown that. The studies that found a testosterone-related change tested it only as part of a blend with other ingredients that can independently affect hormones, so the change can't be credited to saw palmetto specifically.
Does saw palmetto lower testosterone?
The largest trial to measure a related outcome (sexual function, in the CAMUS trial) found no difference from placebo, even at triple the standard dose over 72 weeks. No trial found saw palmetto alone lowering testosterone.
Does saw palmetto affect libido or sex drive?
The CAMUS trial measured sexual function as a secondary outcome across 369 men and found no difference between saw palmetto and placebo. A systematic review of adverse events lists decreased libido among the commonly reported side effects across studies, which points the opposite direction from a libido benefit, though causality in individual reports isn't established either.
Can saw palmetto increase testosterone in women?
No trial has tested saw palmetto's effect on testosterone in women specifically, alone or in a blend. See what does saw palmetto do for women for what has been studied.
When to talk to a doctor
Saw palmetto is not a treatment for low testosterone, hypogonadism, or sexual dysfunction. Fatigue, low libido, or other symptoms sometimes attributed to low testosterone can have several causes and are worth discussing with a doctor, including an actual blood test, rather than addressing with an unproven supplement.
Related reading: does saw palmetto help hair growth, what does saw palmetto do for men, and saw palmetto benefits: what the research does and doesn't show.
Sources
- Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial A 72-week randomized trial that escalated saw palmetto up to triple the standard dose (960 mg/day) in 369 men found it did not reduce urinary symptoms more than placebo at any dose tested.
- Serenoa repens (Permixon) inhibits the 5alpha-reductase activity of human prostate cancer cell lines without interfering with PSA expression A laboratory study found one specific saw palmetto extract blocked an enzyme that converts testosterone to DHT in cultured prostate cells, without lowering PSA production in those cells — a cell-culture finding, not proof it changes hormone levels in someone taking a capsule.
- Evaluation of Resettin® on serum hormone levels in sedentary males A small crossover trial of a saw palmetto-and-astaxanthin blend found reduced DHT and estradiol versus placebo at the higher dose, and a 38% testosterone increase that wasn't statistically significant — a two-ingredient blend result, not evidence of saw palmetto's effect alone.
- Effects of androstenedione-herbal supplementation on serum sex hormone concentrations in 30- to 59-year-old men A blend dominated by androstenedione (a testosterone precursor) plus five other ingredients including saw palmetto raised free testosterone and DHT in men — an effect the trial's own authors attributed to the blend as a whole, not to saw palmetto specifically.
- Analysis of androgen modulation by natural products A 2026 review of botanicals and hormones singled out saw palmetto as an example where a plausible mechanism (blocking an enzyme linked to testosterone conversion) hasn't translated into positive human trial results, unlike a few other herbs with modest evidence for raising testosterone.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.