Saw Palmetto

Common name: Sabal

Botanical names: Serenoa serrulata, Serenoa repens, Sabal serrulata

Photo

© 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):

Science Ratings Health Concerns
3Stars

Benign prostatic hyperplasia (BPH)
1Star

Prostatitis (NBP)
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

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.

There is one case report in which the use of saw palmetto was thought to be the cause of pancreatitis in a middle-aged man, although a cause-effect relationship was not conclusively proven.13

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.

13. Jibrin I, Erinle A, Saidi A, Aliyu ZY. Saw palmetto-induced pancreatitis. South Med J 2006;99:611–2.