Supplement
Saw Palmetto
Herbs · Serenoa repens, Sabal serrulata, saw palmetto, saw palmetto berries, sabal fruit, Permixon (hexane extract)
Saw palmetto is a low-growing palm from the southeastern US; its fruits provide one of the most widely used herbal remedies for the prostate. In Germany it is available as a herbal medicine and as a dietary supplement. It is very well tolerated, but the studies diverge considerably on its effect on symptoms.
In short
Saw palmetto extract is taken mainly for complaints caused by a benignly enlarged prostate, that is, frequent urge to urinate, a weak stream and nighttime urination. For one particular French hexane extract, meta-analyses show fewer nighttime trips to the toilet and better urine flow, and in a comparison with the standard drug tamsulosin, symptoms improved to the same extent over 12 months. The large independent placebo-controlled trials and the 2023 Cochrane review, by contrast, found hardly any noticeable difference from placebo. The good tolerability is undisputed, with no consequences for sexual function or PSA level. For hair loss there are only a few small studies.
What it is
Serenoa repens, also called Sabal serrulata, grows as a low palm in Florida and the southeastern US. The ripe, dried fruits are used. From them, an oily extract is obtained that consists of up to 90 percent free fatty acids, plus small amounts of plant sterols. The fruits have long been used in herbal medicine for prostate complaints; in Germany there has been a Commission E monograph on them since 1989.
What matters is how the extract is produced. In France it is mainly extracted with hexane, in Germany mostly with 90 to 96 percent ethanol. The proportion of free fatty acids varies between 40 and 81 percent depending on the product. The German guideline therefore stresses that results from studies with one extract cannot simply be transferred to another manufacturer’s product.
How it is supposed to work
Several effects are attributed to the free fatty acids: they are said to slow the enzyme 5-alpha reductase, which converts testosterone into the more potent dihydrotestosterone, to act antiandrogenically and anti-inflammatorily, and to dampen growth factors in the prostate. 5-alpha reductase is also the target of prostate drugs such as finasteride, hence the reputation as a herbal alternative.
In humans, this chain is not cleanly established. The European Medicines Agency explicitly states in its monograph that the mechanism of action is not known. Saw palmetto does not change the PSA level more than placebo even at three times the standard dose, which argues against a strong hormonal effect in the prostate. According to the guideline, many of the effects, mostly observed in the laboratory, occurred in part at dosages that cannot be reached in humans.
What users are looking for
Most men take saw palmetto from around age 50, when the urge to urinate comes at night and they do not yet want a drug, often because they fear side effects such as ejaculation disorders or loss of libido. Many report that they have to get up less often. These are anecdotal reports, and with prostate complaints in particular, symptoms also improve markedly under placebo, in the CAMUS trial even somewhat more than under saw palmetto. Saw palmetto is also used against hair loss because of its presumed antiandrogenic effect, including by women.
What is well supported
Tolerability is best supported. In the Cochrane review, side effects occurred just as often under saw palmetto as under placebo, in 12 studies with 2,399 participants. A systematic review of 40 papers found only mild complaints such as abdominal pain, diarrhea or headache. Unlike many prostate drugs, sexual function and PSA level remain unaffected, so the PSA test for cancer screening is not distorted.
For one extract there are also positive efficacy data. The EMA classifies the French hexane extract as a medicine with well-established medicinal use, the stronger of two categories for herbal medicines. A meta-analysis of 27 studies with 5,800 patients on this extract found 0.64 fewer nighttime trips to the toilet and urine flow improved by 2.75 ml/s compared with placebo. In the large European PERMAL trial, it improved symptoms over 12 months just as much as tamsulosin, without its ejaculation disorders. The German S2e guideline therefore considers herbal medicines an option for men with mild to moderate symptoms who reject chemical drugs.
What the studies show
The CAMUS trial
369 men aged 45 and over received saw palmetto extract or placebo for 72 weeks. The dose was increased from 320 mg via 640 mg to 960 mg per day to test whether more helps. The symptom score fell by 2.20 points under saw palmetto and by 2.99 points under placebo. Saw palmetto was not better on any of the other endpoints, such as nighttime urination, urine flow or sexual function. There were no clearly attributable side effects.
The PERMAL trial
In 11 European countries, 704 men were treated double-blind for one year with either 320 mg of hexane extract or 0.4 mg of tamsulosin. The symptom score fell by 4.4 points in both groups, and urine flow rose by 1.8 and 1.9 ml/s respectively. Ejaculation disorders were more common under tamsulosin. There was no placebo group, so it cannot be said how much of the improvement is due to the placebo effect.
The 2023 Cochrane review
The analysis comprises 27 studies with 4,656 participants. In the studies with a low risk of bias, saw palmetto improved the symptom score after 3 to 6 months by 0.90 points on a scale up to 35; the authors rate this as little or no difference. After 12 to 17 months, no difference was measurable any more. According to the review, the conclusions have high certainty.
Where the data stop
The independent, large placebo-controlled trials argue against a noticeable effect on symptoms. In the American STEP trial with 225 men, neither the symptom score nor urine flow, prostate size or residual urine changed over one year compared with placebo; in CAMUS, even three times the dose did not help. The positive findings come predominantly from studies with the French hexane extract, the meta-analysis on it is close to the manufacturer, and the comparisons with tamsulosin have no placebo group. According to the German guideline, this extract is not offered in Germany; most products here are ethanolic extracts, for which the EMA recognizes only traditional use.
Herbal medicines do not affect prostate volume or a genuine outflow obstruction; the guideline explicitly advises against them in clearly obstructive findings. For hair loss, the situation is even thinner: a review found 5 small randomized studies and 2 cohort studies, often with combination products, and the most recent study with 60 participants tested a manufacturer’s own extract. A comparison with finasteride or minoxidil in a large independent study is lacking.
Status, approval and legal
Saw palmetto has a dual status in Germany. Extracts from saw palmetto fruits are on the market as herbal medicines, not prescription-only and, since 2004, generally not reimbursed by statutory health insurance. The EMA’s 2016 EU monograph recognizes the hexane extract as well-established medicinal use and ethanolic extracts as traditional use, in each case only for adult men. At the same time, the fruit is permitted as an ingredient in dietary supplements; according to the substance list of the BVL (German Federal Office of Consumer Protection and Food Safety), it is not considered a novel food there. Dietary supplements, however, may not be advertised for relieving prostate complaints. There are no maximum amounts from EFSA, BfR or DGE. Saw palmetto is not on the 2026 WADA Prohibited List.
Safety
Saw palmetto is one of the best-tolerated herbal medicines. According to the EMA, abdominal pain and headache are common; occasionally there is nausea, an increase in liver values, skin rash and a reversible enlargement of the mammary gland. The liver injury database LiverTox associates saw palmetto with rare liver damage but considers its role uncertain. With blood thinners such as warfarin, some suspected cases of elevated clotting values have been reported; this should be clarified with a physician. Saw palmetto is not intended for women, children and adolescents; data on pregnancy and fertility are lacking. Above all, it is important to have prostate complaints checked by a physician beforehand. With blood in the urine, fever, pain when urinating or urinary retention, one should see a doctor.
BK-Score Supported, with caveats
| Human evidence | 7 | |
|---|---|---|
| Mechanism | 4 | |
| Safety data | 8 | |
| Hype gap | 4 | |
| Track record of use | 8 |
Evidence 7, because there are many RCTs, including large ones (CAMUS 369 men over 72 weeks, STEP 225 men over 1 year, PERMAL 704 men over 12 months), but the results are inconsistent: the 2023 Cochrane review with 27 studies and 4,656 participants found only -0.90 points on the IPSS for saw palmetto alone and thus hardly any difference from placebo (high certainty), while the manufacturer-related meta-analysis on the hexane extract (Vela-Navarrete 2018, 5,800 patients) shows less nocturia and better urine flow. Mechanism 4, because 5-alpha reductase inhibition and antiandrogenic effects have been described mainly in the laboratory, the EMA describes the mechanism of action as unknown, and the PSA level remains unchanged even at 960 mg per day (Andriole 2013). Safety 8, because controlled data up to 72 weeks, a systematic review of 40 papers (Agbabiaka 2009) and decades of experience as an approved herbal medicine with an EU monograph are available; side effects were not more frequent than under placebo (RR 1.01). Hype 4, because saw palmetto is promoted as a herbal prostate and hair solution, although the independent studies show hardly any effects on prostate complaints and the hair data rest on a few small studies. Use 8, because saw palmetto fruits have been used under drug regulation for decades (Commission E 1989, EU monograph 2016). Direction mixed: one particular extract shows positive results; the independent placebo-controlled trials and Cochrane argue against a noticeable effect.
The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)
Frequently asked questions about saw palmetto
Does saw palmetto help with an enlarged prostate?
The data are mixed. The 2023 Cochrane review found hardly any noticeable difference in symptoms compared with placebo. For a French hexane extract, meta-analyses show less nighttime urination and better urine flow, and in a large trial it worked as well as tamsulosin.
Is saw palmetto as effective as finasteride or tamsulosin?
Compared with tamsulosin, symptoms improved to the same extent with the hexane extract over 12 months, though without a placebo group. According to the German guideline, herbal medicines affect neither prostate volume nor an outflow obstruction. For clearly obstructive symptoms, saw palmetto therefore does not replace treatment.
Does saw palmetto distort the PSA level?
No. In the CAMUS trial, the PSA level did not change more than under placebo even at three times the standard dose. The test for early detection of prostate cancer thus remains meaningful.
Does saw palmetto help against hair loss?
There are first positive indications from small studies, often with combination products and in part close to manufacturers. Large independent studies and comparisons with finasteride or minoxidil are lacking. The effect can therefore not be considered established.
Does saw palmetto have side effects?
It is very well tolerated; in studies, side effects did not occur more often than under placebo. Abdominal pain and headache, nausea and rarely elevated liver values are possible. Anyone taking blood thinners such as warfarin should clarify its use with a physician.
Is saw palmetto a medicine or a dietary supplement?
In Germany, both. There are approved herbal medicines with saw palmetto extract that are available without prescription in pharmacies. In addition, saw palmetto is sold as a dietary supplement, but may not be advertised there for relieving prostate complaints.
Related
- Same goal: Hormone balanceBlack Cohosh (Cimicifuga)
- Same goal: Hormone balanceChasteberry (Vitex agnus-castus)
- Same goal: Hormone balanceTribulus Terrestris
- Same goal: Skin, hair, nailsMSM (Methylsulfonylmethane)
- Same goal: Hormone balanceTongkat Ali
- Same goal: Skin, hair, nailsBiotin (Vitamin B7)
Sources
- Franco et al., Cochrane Database Syst Rev 2023 – Serenoa repens for complaints caused by prostate enlargement
- Barry et al., JAMA 2011 – increasing doses of saw palmetto for urinary tract symptoms (CAMUS)
- Bent et al., N Engl J Med 2006 – saw palmetto for benign prostatic hyperplasia (STEP)
- Vela-Navarrete et al., BJU Int 2018 – meta-analysis on the hexane extract
- Debruyne et al., Eur Urol 2002 – hexane extract versus tamsulosin (PERMAL)
- Andriole et al., J Urol 2013 – saw palmetto and PSA level
- EMA/HMPC – EU herbal monograph Serenoa repens, fructus
- DGU – S2e guideline on the diagnosis and treatment of benign prostatic syndrome 2023
- Agbabiaka et al., Drug Saf 2009 – systematic review of adverse effects
- Evron et al., Skin Appendage Disord 2020 – saw palmetto for hair loss
Open in the database – with search, filters and comparison (German app)
Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-09-27.