Saw palmetto ( Serenoa repens , Sabal serrulata ) is used popularly in Europe for symptoms associated with benign prostatic hypertrophy (enlargement of the prostate). Although not considered standard of care in the United States, it is the most popular herbal treatment for this condition.
Historical use of saw palmetto can be traced in the Americas to the Mayans who used it as a tonic and to the Seminoles who took the berries as an expectorant and antiseptic.
Saw palmetto was listed in the United States Pharmacopeia from 1906 to 1917 and in the National Formulary from 1926 to 1950. Saw palmetto extract is a licensed product in several European countries.
Multiple mechanisms of action have been proposed, and saw palmetto appears to possess 5-α-reductase inhibitory activity (thereby preventing the conversion of testosterone to dihydrotestosterone). Hormonal/estrogenic effects have also been reported, as well as direct inhibitory effects on androgen receptors and anti-inflammatory properties.
Enlarged prostate (benign prostatic hypertrophy/BPH)
Numerous human trials report that saw palmetto improves symptoms of benign prostatic hypertrophy (BPH) such as nighttime urination, urinary flow, and overall quality of life, although it may not greatly reduce the size of the prostate. The effectiveness may be similar to the medication finasteride (Proscar®) with fewer side effects. Although the quality of these studies has been variable, overall they suggest effectiveness. Saw palmetto has not been thoroughly compared to other types of drugs used for BPH, such as doxazosin (Cardura®) or terazosin (Hytrin®). Most available studies have assessed the standardized saw palmetto product Permixon®. Although a 2003 study by Willetts et al. reported no difference over a 12-week period and a 2006 well-designed study by Bent et al. reported no difference over a 12-month period, overall the weight of available scientific evidence favors the effectiveness of saw palmetto over placebo. A
Male-pattern hair loss
It has been suggested that saw palmetto may block some effects of testosterone and therefore reduce male pattern hair loss, similar to the medication finasteride (Propecia®). More studies are necessary before saw palmetto can be recommended for this use. C
Preparation for surgery
(transurethral resection of prostate) Saw palmetto may help the recovery process in patients undergoing prostate surgery. Saw palmetto may reduce bleeding after surgery and also reduce catheter use. More study is needed in this area. C
Prostate cancer
There is not enough scientific evidence to recommend the product PC-SPES® (which contains saw palmetto) for prostate cancer. PC-SPES® also contains seven other herbs ( Chrysanthemum morifolium , Isatis indigotica , Glycyrrhiza glabra , Ganoderma lucidum , Panax pseudo-ginseng , Rabdosia rubescens , and Scutellaria baicalensis ). It has been a popular treatment for prostate cancer, but the U.S. Food and Drug Administration (FDA) has issued a warning not to use PC-SPES® because it contains the anticoagulant chemical warfarin and may cause bleeding. C
Prostatitis/chronic pelvic pain syndrome (CP/CPPS)
A prospective, randomized, open label, one-year study was designed to assess the safety and efficacy of saw palmetto and finasteride in the treatment of men diagnosed with category III prostatitis/chronic pelvic pain (CP/CPPS). CP/CPPS treated with saw palmetto had no appreciable long-term improvement. In contrast, patients treated with finasteride had significant and durable improvement in multiple parameters except for voiding. C
Underactive bladder
There is currently little information on the effectiveness of saw palmetto for the treatment of bladder disorders. C
Key to grades
A Strong scientific evidence for this use
B Good scientific evidence for this use
C Unclear scientific evidence for this use
D Fair scientific evidence against this use (it may not work)
F Strong scientific evidence against this use (it likely does not work)
The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Acne, asthma, athletic performance enhancement, bacterial infections, bladder inflammation, breast feeding, breast enlargement or reduction, bronchitis, cancer, catarrh, cough, cystitis, diabetes, diarrhea, digestive aid, diuretic, dysentery, Epstein-Barr virus, excess hair growth, high blood pressure, hormone imbalances (estrogen or testosterone), immune stimulation, impotence, indigestion, inflammation, laryngitis, menstrual pain, migraine headache, muscle or intestinal spasms, ovarian cysts, pain, polycystic ovarian syndrome, postnasal drip, reproductive organ problems, sedation, sexual vigor, sore throat, spasms, sperm production, sweating, testicular wasting (atrophy), upper respiratory tract infection, uterine or vaginal disorders.
Selected references
Avins AL, Bent S. Saw palmetto and lower urinary tract symptoms: what is the latest evidence? Curr Urol Rep 2006 Jul;7(4):260-5.
Bent S., Kane C., Shinohara K., et al. Saw palmetto for benign prostatic hyperplasia. N Engl.J Med 2-9-2006;354(6):557-566.
Boyle P., Robertson C., Lowe F., et al. Meta-analysis of clinical trials of permixon in the treatment of symptomatic benign prostatic hyperplasia. Urology 2000;55(4):533-539.
Braeckman J, Denis L, de Leval J, et al. A double-blind, placebo-controlled study of the plant extract Serenoa repens in the treatment of benign hyperplasia of the prostate. Eur J Clin Res 1997;9:247-259.
Edwards JL. Diagnosis and management of benign prostatic hyperplasia. Am Fam Physician. 2008 May 15;77(10):1403-10.
Engelmann U, Walther C, Bondarenko B, et al. Efficacy and safety of a combination of sabal and urtica extract in lower urinary tract symptoms. A randomized, double-blind study versus tamsulosin. Arzneimittelforschung. 2006;56(3):222-9.
Feifer AH, Fleshner NE, et al. Analytical accuracy and reliability of commonly used nutritional supplements in prostate disease. J.Urol 2002;168(1):150-154.
Gerber GS, Zagaja GP, Bales GT, et al. Saw palmetto (Serenoa repens) in men with lower urinary tract symptoms: effects on urodynamic parameters and voiding symptoms. Urology 1998;51(6):1003-1007.
Gerber GS, Kuznetsov D, Johnson BC, et al. Randomized, double-blind, placebo-controlled trial of saw palmetto in men with lower urinary tract symptoms. Urology 2001;58(6):960-964.
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;171(1):284-288.
Magri V, Trinchieri A, Pozzi G, et al. Efficacy of repeated cycles of combination therapy for the eradication of infecting organisms in chronic bacterial prostatitis. Int J Antimicrob Agents 2007 May;29(5):549-56.
Preuss HG, Marcusen C, Regan J, et al. 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):217-225.
Veltri RW, Marks LS, Miller MC, et al. Saw palmetto alters nuclear measurements reflecting DNA content in men with symptomatic BPH: evidence for a possible molecular mechanism. Urology 2002;60(4):617-622.
Willetts KE, Clements MS, Champion S, et al. A. Serenoa repens extract for benign prostate hyperplasia: a randomized controlled trial. BJU Int 2003;92(3):267-270.
Wilt TJ, Ishani A, Stark G, et al. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA 11-11-1998;280(18):1604-1609.
Drug Saf. 2009;32(8):637-47. Serenoa repens (saw palmetto): a systematic review of adverse events. Agbabiaka TB, Pittler MH, Wider B, Ernst E.Complementary Medicine, Peninsula Medical School, Universities of Exeter and Plymouth, Exeter EX2 4NT, United Kingdom.
Serenoa repens (W. Bartram) Small, also known as saw palmetto, is one of the most widely used herbal preparations for the treatment of lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH). Although a number of randomized controlled trials (RCTs) and systematic reviews of the efficacy of S. repens for the treatment of LUTS and BPH have been published, no systematic review on its drug interactions or adverse events currently exists. This review assesses all available human safety data of S. repens monopreparations. Systematic literature searches were conducted from date of inception to February 2008 in five electronic databases; reference lists and our departmental files were checked for further relevant publications. Information was requested from spontaneous reporting schemes of the WHO and national safety bodies. Twenty-four manufacturers/distributors of S. repens preparations and four herbalist organizations were contacted for additional information. No language restrictions were imposed. Only reports of adverse events in humans from monopreparations of S. repens were included. Data from all articles, regardless of study design, reporting adverse events or interactions were independently extracted by the first author and validated by the second. Forty articles (26 randomized controlled trials, 4 non-randomized controlled trials, 6 uncontrolled trials and 4 case reports/series) were included. They suggest that adverse events associated with the use of S. repens are mild and similar to those with placebo. The most frequently reported adverse events are abdominal pain, diarrhoea, nausea, fatigue, headache, decreased libido and rhinitis. More serious adverse events such as death and cerebral haemorrhage are reported in isolated case reports and data from spontaneous reporting schemes, but causality is questionable. No drug interactions were reported. Currently available data suggest that S. repens is well tolerated by most users and is not associated with serious adverse events. The majority of adverse events are mild, infrequent and reversible, and include abdominal pain, diarrhoea, nausea and fatigue, headache, decreased libido and rhinitis. We found no evidence for drug interactions with S. repens. However, higher quality reporting of adverse events is essential if safety assessments are to be improved in future.