Botanical names: Serenoa serrulata, Serenoa
repens, Sabal serrulata
© Steven Foster
Parts used and where grown
Saw palmetto (sometimes referred to as sabal in Europe) is a native of the southeast United
States. The berries of the plant are used medicinally.
Saw palmetto has been used
in connection with the following conditions (refer to the individual
health concern for complete information):
Historical or traditional use (may
or may not be supported by scientific studies)
In the early part of the twentieth century, saw palmetto berry tea was commonly recommended
by herbalists for a variety of urinary tract ailments in men. Some believed the berry
increased sperm production and sex drive in men.
Active constituents
The liposterolic (fat-soluble) extract of saw palmetto provides concentrated amounts of
free fatty acids and sterols. One study with a saw palmetto extract suggests that it reduces
the amount of dihydrotestosterone (DHT) (an active form of testosterone) binding in the part
of the prostate surrounding the urethra (the tube carrying urine from the
bladder).1 Test tube studies also suggest that saw palmetto weakly inhibits the
action of 5-alpha-reductase, the enzyme responsible for converting testosterone to
DHT.2 In test tubes, saw palmetto also inhibits the actions of growth factors and
inflammatory substances that may contribute to
benign prostatic hyperplasia (BPH). Contrary to some opinions, saw palmetto does not have
an estrogen-like effect in men’s bodies.
Over the last decade, double-blind clinical trials have proven that 320 mg per day of the
liposterolic extract of saw palmetto berries is a safe and effective treatment for the
symptoms of BPH. A recent review of studies,
published in the Journal of the American Medical Association, concluded that saw
palmetto extract was as effective as
finasteride (Proscar®) in the treatment of BPH.3 The clinical
effectiveness of saw palmetto has been shown in trials lasting six months to three years.
A three-year trial in Germany found that taking 160 mg of saw palmetto extract twice daily
reduced nighttime urination in 73% of patients and improved urinary flow rates
significantly.4 In a double-blind trial, 160 mg of saw palmetto extract taken twice
daily was found to treat BPH as effectively as finasteride (Proscar) without side effects,
such as loss of libido.5
Saw palmetto extract has also been combined with a nettle root extract to successfully treat BPH. One
trial using a combination of saw palmetto extract (320 mg per day) and nettle root extract
(240 mg per day) showed positive actions on symptoms of BPH (e.g. improved urine flow,
decreased nighttime urination, etc.) over a one-year treatment period.6 Another
study compared the same combination to finasteride for one year with positive
results.7
How much is usually taken?
For early-stage BPH, 160 mg per day of
liposterolic saw palmetto herbal extract in capsules is taken two times per day. One trial
suggested that 320 mg once per day may be equally effective.8 It may take four to
six weeks to see results with BPH. If improvement is noted, the saw palmetto should be used
continuously. It is important to work closely with a urologist to determine clinical
improvement. Although it has not been tested for efficacy, saw palmetto is occasionally taken
as a tea made with 5–6 grams of the powdered dried fruit. Ground, nonstandardized berry
preparations (1–2 grams per day) and liquid extracts of whole herb at 5–6 ml per
day are also sometimes used but have not been specifically tested.
Are there any side effects or interactions?
No significant side effects have been noted in clinical trials with saw palmetto extracts.
However, in rare cases, saw palmetto can cause stomach problems,9 and one
individual who was taking saw palmetto developed severe bleeding during surgery.10
According to some clinical trials, saw palmetto extract does not appear to interfere with
accurate measuring of prostate-specific antigen (PSA)—a marker for prostate cancer.11 One test tube study
found that saw palmetto did not prevent the release of PSA from prostate cells.12
Saw palmetto is most effective in managing symptoms of BPH but has not been shown to
aggressively shrink the size of the prostate. BPH can only be diagnosed by a physician
(preferably a urologist). Use of saw palmetto extract for BPH should only occur after a
thorough workup and diagnosis by a doctor. There are no proven uses of saw palmetto for
women.
At the time of writing, there were no well-known drug interactions
with saw palmetto.
References:1. Di Silverio F, Monti S, Sciarra A, et al. Effects of long-term
treatment with Serenoa repens (Permixon®) on the concentrations and regional distribution
of androgens and epidermal growth factor in benign prostatic hyperplasia. Prostate
1998;37:77–83.
2. Strauch G, Perles P, Vergult G, et al. Comparison of finasteride
(Proscar®) and Serenoa repens (Permixon®) in the inhibition of 5-alpha
reductase in healthy male volunteers. Eur Urol 1994;26:247–52.
3. Wilt TJ, Ishani A, Stark G, et al. Saw palmetto extracts for treatment
of benign prostatic hyperplasia. JAMA 1998;280:160–9.
4. Bach D, Ebeling L. Long-term drug treatment of benign prostatic
hyperplasia—results of a prospective 3-year multicenter study using Sabal extract IDS
89. Phytomedicine 1996;3:105–11.
5. Carraro JC, Raynaud JP, Koch G, et al. Comparison of phytotherapy
(Permixon®) with finasteride in the treatment of benign prostate hyperplasia: A
randomized international study of 1,098 patients. Prostate 1996;29:231–40.
6. Metzker H, Kieser M, Hölscher U. Efficacy of a combined
Sabal-Urtica preparation in the treatment of benign prostatic hyperplasia (BPH).Urologe
[B] 1996;36:292–300.
7. Sökeland J, Albrecht J. A combination of Sabal and Urtica
extracts versus finasteride in BPH (stage I and II according to Alken): a comparison of
therapeutic efficacy in a one-year double-blind study. Urologe [A]
1997;36:327–33.
8. Brown DJ. Herbal Prescriptions for Better Health. Rocklin,
CA: Prima Publications, 1996, 167–72.
9. Blumenthal M, Busse WR, Goldberg A, et al. (eds). The Complete
Commission E Monographs: Therapeutic Guide to Herbal Medicines. Boston, MA: Integrative
Medicine Communications, 1998, 201.
10. Cheema P, El-Mefty O, Jazieh AR. Intraoperative haemorrhage
associated with the use of extract of Saw Palmetto herb: a case report and review of
literature. J Intern Med 2001;250:167–9.
11. Carraro JC, Raynaud JP, Koch G, et al. Comparison of phytotherapy
(Permixon®) with finasteride in the treatment of benign prostate hyperplasia: A
randomized international study of 1,098 patients. Prostate 1996;29:231–40.
12. Bayne CW, Donnelly F, Ross M, Habib FK. Serenoa repens (Permixon): a
5alpha-reductase types I and II inhibitor—new evidence in a coculture model of BPH.
Prostate 1999;40:232–41.