Saw palmetto (Serenoa repens) is a dwarf (2-4 feet in height) palm tree found in the United States from the Carolinas to Texas. For centuries, the crude extracts of saw palmetto have been used to improve sperm production and to increase breast size and sexual vigor, but its most effective and only scientifically based use is to improve the symptoms of benign prostatic hyperplasia (BPH).
The premise for using saw palmetto is that it maintains normal prostate health by decreasing the metabolism and action of male steroids. Saw palmetto has been demonstrated to decrease the activity of 5-alpha reductase which stimulates the conversion of testosterone to dihydrotestosterone (DHT), its more active form. Since DHT is necessary for excessive growth (hyperplasia) of the prostate and is elevated in men with BPH, inhibition of 5-alpha reductase, and therefore DHT production, may alleviate BPH and the associated compression of the urethra (the tube that runs through the prostate gland to carry urine from the bladder). Additionally, studies have shown that saw palmetto helps to inhibit the production of various inflammatory factors, probably due to an effect of the fatty acids, thus serving to decrease overall prostate inflammation. The prescription medication for treating BPH, finasteride, is available as Proscar for BPH and a lower potency version called Propecia for treating hair loss in men (because the same conversion of testosterone to DHT is thought to result in thinning and loss of hair in men).
Considering that the possible health benefits are similar to the prescription drugs Proscar for BPH and Propecia for hair loss, and the fact that saw palmetto appears to be safe and effective and without side effects, in several scientific studies, saw palmetto should be considered an outstanding choice for natural therapy in diagnosed cases of BPH.
Although studies of saw palmetto as a treatment for prostatitis has been disappointing (Kaplan et al. 2004), its effectiveness in treating BPH is supported by numerous well-controlled clinical trials. In one study of 155 men with BPH, International Prostate Symptom Scores (IPPS) and quality of life (QOL) were improved, as were measures of sexual function and prostate size following 6 months of supplementation with 320mg/d of saw palmetto extract (Pytel et al. 2002). In another study of 100 male outpatients, both 320mg/d and 480mg/d of saw palmetto extract for 3 months had similar significant effects in improving QOL scores, maximum and mean urinary flow rates, and residual urinary volume (Gainnakopoulos et al. 2002, Gerber et al. 2001). Several other smaller studies of saw palmetto extracts (160mg twice daily) have shown significant improvements in symptoms of BPH (Gerber et al. 1998) that are comparable to effects seen with drug treatment with the synthetic 5-alpha-reductase inhibitor finasteride (Sokeland 2000) such as improvements in maximum urinary flow rates, reduced trips to the bathroom, a greater ability to fully empty the bladder and an increased quality of life.
Because saw palmetto has primarily been tested in adult males, it is not recommended for children, or for women who are pregnant or lactating. No drug interactions have been reported for saw palmetto (Markowitz et al. 2003). It is important to note that saw palmetto extract may only treat the symptoms of BPH, and therefore those with an enlarged prostate should consult with their physician on a regular basis to rule out prostate cancer or other causes of hypertrophy. Doses in clinical studies have typically used 160mg of the oil-based (“lipophilic”) berry extract taken twice a day (morning and evening) for at least 30 days (total daily dose of 320mg). Effective products are standardized for fatty acid and sterol content – approximately 80-90% total fatty acids and sterols is recommended.
1.Bauer HW, Casarosa C, Cosci M, Fratta M, Blessmann G. Saw palmetto fruit extract for treatment of benign prostatic hyperplasia. Results of a placebo-controlled double-blind study. MMW Fortschr Med. 1999 Jun 24;141(25):62.
2.Brown GA, Vukovich MD, Martini ER, Kohut ML, Franke WD, Jackson DA, King DS. Effects of androstenedione-herbal supplementation on serum sex hormone concentrations in 30- to 59-year-old men. Int J Vitam Nutr Res. 2001 Sep;71(5):293-301.
3.Brown GA, Vukovich MD, Martini ER, Kohut ML, Franke WD, Jackson DA, King DS. Endocrine and lipid responses to chronic androstenediol-herbal supplementation in 30 to 58 year old men. J Am Coll Nutr. 2001 Oct;20(5):520-8.
4.Brown GA, Vukovich MD, Reifenrath TA, Uhl NL, Parsons KA, Sharp RL, King DS. Effects of anabolic precursors on serum testosterone concentrations and adaptations to resistance training in young men. Int J Sport Nutr Exerc Metab. 2000 Sep;10(3):340-59.
5.Gerber GS, Kuznetsov D, Johnson BC, Burstein JD. Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptoms. Urology. 2001 Dec;58(6):960-4; discussion 964-5.
6.Gerber GS, Zagaja GP, Bales GT, Chodak GW, Contreras BA. Saw palmetto (Serenoa repens) in men with lower urinary tract symptoms: effects on urodynamic parameters and voiding symptoms. Urology. 1998 Jun;51(6):1003-7.
7.Gerber GS. Saw palmetto for the treatment of men with lower urinary tract symptoms. J Urol. 2000 May;163(5):1408-12.
8.Giannakopoulos X, Baltogiannis D, Giannakis D, Tasos A, Sofikitis N, Charalabopoulos K, Evangelou A. The lipidosterolic extract of Serenoa repens in the treatment of benign prostatic hyperplasia: a comparison of two dosage regimens. Adv Ther. 2002 Nov-Dec;19(6):285-96.
9.Kaplan SA, Volpe MA, Te AE. A prospective, 1-year trial using saw palmetto versus finasteride in the treatment of category III prostatitis/chronic pelvic pain syndrome. J Urol. 2004 Jan;171(1):284-8.
10.Markowitz JS, Donovan JL, Devane CL, Taylor RM, Ruan Y, Wang JS, Chavin KD. Multiple doses of saw palmetto (Serenoa repens) did not alter cytochrome P450 2D6 and 3A4 activity in normal volunteers. Clin Pharmacol Ther. 2003 Dec;74(6):536-42.
11.Marks LS, Partin AW, Epstein JI, Tyler VE, Simon I, Macairan ML, Chan TL, Dorey FJ, Garris JB, Veltri RW, Santos PB, Stonebrook KA, deKernion JB. Effects of a saw palmetto herbal blend in men with symptomatic benign prostatic hyperplasia. J Urol. 2000 May;163(5):1451-6.
12.McPartland JM, Pruitt PL. Benign prostatic hyperplasia treated with saw palmetto: a literature search and an experimental case study. J Am Osteopath Assoc. 2000 Feb;100(2):89-96.
13.Preuss HG, Marcusen C, Regan J, Klimberg IW, Welebir TA, Jones WA. Randomized trial of a combination of natural products (cernitin, saw palmetto, B-sitosterol, vitamin E) on symptoms of benign prostatic hyperplasia (BPH). Int Urol Nephrol. 2001;33(2):217-25.
14.Pytel YA, Vinarov A, Lopatkin N, Sivkov A, Gorilovsky L, Raynaud JP. Long-term clinical and biologic effects of the lipidosterolic extract of Serenoa repens in patients with symptomatic benign prostatic hyperplasia. Adv Ther. 2002 Nov-Dec;19(6):297-306.
15.Segars LW. Saw palmetto extracts for benign prostatic hyperplasia. J Fam Pract. 1999 Feb;48(2):88-9.
16.Sokeland J. Combined sabal and urtica extract compared with finasteride in men with benign prostatic hyperplasia: analysis of prostate volume and therapeutic outcome. BJU Int. 2000 Sep;8 6(4):439-42.
17.Veltri RW, Marks LS, Miller MC, Bales WD, Fan J, Macairan ML, Epstein JI, Partin AW. Saw palmetto alters nuclear measurements reflecting DNA content in men with symptomatic BPH: evidence for a possible molecular mechanism. Urology. 2002 Oct;60(4):617-22.
18.Wilt TJ, Ishani A, Stark G, MacDonald R, Lau J, Mulrow C. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA. 1998 Nov 11;280(18):1604-9.
EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.