Saw palmetto has been used to treat symptoms of benign prostatic hyperplasia (BPH), but evidence from quality clinical trials and a meta-analysis does not support this use. Data suggesting a positive effect on erectile dysfunction are limited, and results from studies evaluating the effect of saw palmetto on outcomes of transurethral resection of the prostate surgery are equivocal.
Contraindications have not been identified. Use in children younger than 12 years is not recommended.
Information regarding safety and efficacy in pregnancy and lactation is lacking. Because saw palmetto affects androgen and estrogen metabolism, and there is no rationale for use in this population, saw palmetto should be avoided.
See Drug Interactions section.
Results from clinical trials note that saw palmetto products are generally well tolerated, with occasional reports of adverse GI effects and headache.
Information is limited.
Saw palmetto is a low, scrubby palm that grows in the coastal plain of Florida and other southeastern states. Its fan-shaped leaves have sharp saw-toothed edges that give the plant its name. Dense clumps of saw palmetto can form an impenetrable thicket. The plant has a characteristic creeping rhizome, one end of which appears above ground. The sweet-smelling fruit is dark brown to black, with a smooth drupe and a single flattened, reddish brown seed. The abundant 2 cm long berries are harvested in the fall and dried for medicinal use. They also serve as a source of nutrition for deer, bears, and wild pigs.1, 2
Native tribes of Florida relied on saw palmetto berries for food; however, Europeans often found the taste of the berries objectionable. While native medicinal use is not recorded, saw palmetto was introduced into Western medical practice in the 1870s and was favored by eclectic medical practitioners for prostate and other urologic conditions. Saw palmetto berries were officially included in the US Pharmacopeia (USP) in 1906 and 1916 and in the National Formulary from 1926 to 1950. While use in the United States declined after that time, saw palmetto has long been a staple phytomedicine in Europe. However, interest in the plant has been rekindled, and saw palmetto is ranked among the top 10 herbal products in the United States, primarily for its use in BPH. Folkloric uses include for baldness, to increase appetite, to build and strengthen tissue, to increase metabolism, for thyroid disorders, for asthma and chest congestion, and for polycystic ovary syndrome.3, 4, 5, 6
Saw palmetto berries primarily contain free fatty acids (70% to 95%) and their ethyl esters, 0.2% to 0.5% phytosterols (beta-sitosterol, stigmasterol, and daucosterol), long-chain alcohols (0.15% to 0.35%), and lipids. The fatty acids include oleic, lauric, myristic, palmitic, linoleic, caproic, caprylic, capric, palmitoleic, steric, and linolenic acids. In addition, flavonoids, polysaccharides, and other minor constituents have been identified. Standards and analytical methods have been described for the extract and its constituents.2, 7, 8, 61 A specific ratio of naturally occurring caproic, caprylic, capric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids to lauric acid are required by USP for authentication. Although little published evidence is available regarding adulteration of products, unpublished analyses by reputable suppliers indicate some adulteration is present in the supply chain. Known adulterants include fruit from a closely related palm species (eg, Acoelorrhaphe wrightii), use of unripe berries, and the addition of vegetable oils to extracts and/or full substitution of saw palmetto extract with other vegetable oils (ie, canola, coconut, olive, palm, peanut, and sunflower oils). The adulteration rate seems to be low (1 of 22 and 0 of 57 products tested in 2 separate analyses) and may also somewhat depend on the weather conditions in the current or immediate prior season.61
Uses and Pharmacology
Benign prostatic hyperplasia
Saw palmetto's mechanism of action in suppressing the symptoms of BPH is poorly understood. Animal and human in vitro studies have led to several different hypotheses, including antiandrogenic and anti-inflammatory activities. Antiproliferative and proapoptotic actions via inhibition of growth factors and inhibition of adipocyte differentiation have also been described.2, 5, 9, 10, 11, 12
An updated Cochrane systematic review and meta-analysis has been published, including data from recent large, high-quality trials. Saw palmetto was no more effective than placebo in decreasing lower urinary tract symptoms associated with BPH in a meta-analysis13, 59 of 3 quality trials, including the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) and Saw palmetto Treatment for Enlarged Prostates (STEP) studies (N = 661).14, 15, 16 The weighted mean difference using validated American Urological Association Symptom Index/International Prostate Symptom Score indices was −0.16 points (95% CI, −1.45 to 1.14) for lower urinary tract symptoms. For increased maximum urinary flow rate, the weighted mean difference was also not significant compared with placebo (0.40 mL/s [95% CI, −0.30 to 1.09]).13 Furthermore, a dose escalation study found no benefit even with triple the usual dosage.14 These findings have similarly been reported by other reviewers, and currently the only place for saw palmetto in the therapy of BPH symptoms is among patients who wish to receive phytotherapy in conjunction with standard medical treatments.17, 18, 19 Results from open-label trials, retrospective analyses, and trials evaluating treatment with combinations of various natural products were not included due to methodological limitations.20, 21, 22 A sponsor-funded phase 2 placebo-controlled, randomized clinical trial (n = 57) conducted in men with BPH found a commercially available herbal formulation containing pumpkin seed oil, lycopene, saw palmetto, pygeum, and Epilobium parviflorum to significantly reduce median international prostate specific scores as well as day time and night time urinary frequency. Improvements were progressive and were observed in several scores at 1 month and in all scores at 3 months.57 The sponsor-funded PROCOMB Italian multicenter, double-blind, double-dummy, randomized trial determined that the combination of saw palmetto, lycopene, selenium (Profluss) plus tamsulosin produced significantly improved prostate symptom scores and Qmax (flow) after 1 year of treatment compared with Profluss or tamsulosin monotherapies in 219 men with BPH/lower urinary tract symptoms.58
Data suggesting a positive effect on erectile dysfunction are limited,5, 21 and results from studies evaluating the effect of saw palmetto on outcomes of transurethral resection of the prostate, particularly the bleeding complication, are equivocal.5, 23, 24
Guidelines have been published concerning the use of saw palmetto to treat lower urinary tract symptoms in men. The American Urological Association guidelines for the management of BPH (2011) conclude that the available data do not suggest that saw palmetto has a clinically meaningful effect on lower urinary tract symptoms secondary to BPH. The guidelines further state that the results of ongoing clinical trials will clarify the potential value of saw palmetto extract in the management of BPH.55 The European Association of Urology guidelines on the management of lower urinary tract symptoms in males (2013) discuss but do not make any specific recommendations on phytotherapy for the treatment of male lower urinary tract symptoms because of variability of products, lack of regulatory infrastructure, and variability in methodologies in the available literature. S. repens was not superior to placebo, finasteride, or tamsulosin with regard to the International Prostate Symptom Score.56
An increase in apoptosis has been documented in mice and in vitro studies.25, 26, 27 Prostate cancer cell proliferation was decreased in an in vitro experiment with saw palmetto berry extract, as well as with beta-sitosterol and stigmasterol.27, 28 No effect on human breast cancer cells was demonstrated.27 In addition, the radiosensitivity of normal prostate cells was increased with exposure to saw palmetto.29
Evidence from quality clinical studies is lacking.
Immunostimulatory activity has been shown in mice.2 Saw palmetto extracts reduced edema induced in the footpads of rats.12 Quality evidence is lacking to support a place in the treatment of alopecia6, 30 or acne.7
Crude saw palmetto berries are usually administered at a dosage of 1 to 2 g/day; however, lipophilic extracts standardized to 85% to 95% fatty acids in soft native extract or 25% fatty acids in a dry extract are more common.
Benign prostatic hyperplasia
320 mg/day standardized extract has been commonly used in clinical trials.13, 14
Pregnancy / Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Because effects on androgen and estrogen metabolism have been identified, and there is no rationale for its use in pregnancy, saw palmetto should not be used in pregnancy or while breastfeeding2
Estrogen Derivatives: Herbs (Estrogenic Properties) may enhance the adverse/toxic effect of Estrogen Derivatives. Monitor therapy.48
Warfarin: Saw Palmetto may enhance the anticoagulant effect of Warfarin. Monitor therapy.49, 50, 51, 52, 53, 54
Use in children younger than 12 years is not recommended because of possible effects on androgen and estrogen metabolism.2 A case report exists of hot flashes in an 11-year-old girl using saw palmetto for hair loss.30
Results from clinical trials note that saw palmetto products are generally well tolerated, with occasional reports of adverse GI effects and headache.2, 7, 13, 32, 35, 36, 37
Cases of coagulopathies have been reported; however, the importance of anticoagulant effects is unclear and caution may be warranted.35, 38, 39, 40, 41 Case reports exist of acute pancreatitis,42, 43 rhabdomyolysis,44 acute hepatotoxicity,45 intraoperative floppy-iris syndrome,46 and hot flashes in an 11-year-old girl using saw palmetto.30
In the 2016 Scientific Statement by the American Heart Association regarding drugs that may cause or exacerbate heart failure, saw palmetto has been recognized as a product with antiplatelet activity which may increase bleeding risk when used with anticoagulants. The guidance noted that naturoceuticals are not recommended for the management of heart failure symptoms or for the secondary prevention of cardiovascular events, and that nutritional supplements are not recommended for the treatment of heart failure [Low-quality; Limited].60
Information is limited. A study in mice found that saw palmetto induced nuclear heterogeneity but not via DNA damage, thus the researchers did not consider it to be genotoxic.47 The relevance of these findings is unclear. No evidence of toxicity was found in the CAMUS clinical trial using 3 times the usual dosage over 18 months.37
1. Serenoa repens. USDA, NRCS. 2006. The PLANTS Database (http://plants.usda.gov, 27 December 2012). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. Accessed December 27, 2012.2. Fructus Serenoae Repentis. In: WHO Monographs on Selected Medicinal Plants. Vol. 2. Geneva, Switzerland: World Health Organization; 2004.3. Bennett BC, Hicklin JR. Uses of saw palmetto (Serenoa repens, Arecaceae) in Florida. Econ Bot. 1998;52(4):381-393.4. Winston, D. Saw Palmetto for Men & Women. Pownal, VT: Storey Books; 1999.5. Geavlete P, Multescu R, Geavlete B. Serenoa repens extract in the treatment of benign prostatic hyperplasia. Ther Adv Urol. 2011;3(4):193-198.219698496. Murugusundram S. Serenoa Repens: Does It have Any Role in the Management of Androgenetic Alopecia? J Cutan Aesthet Surg. 2009;2(1):31-32.203003697. Barnes J. Saw palmetto. Serenoa repens. Also known as Serenoa serrulata, Sabal serrulata and the dwarf palm. J Prim Health Care. 2009;1(4):323.206903438. Schantz MM, Bedner M, Long SE, et al. Development of saw palmetto (Serenoa repens) fruit and extract standard reference materials. Anal Bioanal Chem. 2008;392(3):427-438.186774649. Suzuki M, Ito Y, Fujino T, et al. Pharmacological effects of saw palmetto extract in the lower urinary tract. Acta Pharmacol Sin. 2009;30(3):227-281.1926255010. Iglesias-Gato D, Carsten T, Vesterlund M, Pousette A, Schoop R, Norstedt G. Androgen-independent effects of Serenoa repens extract (Prostasan®) on prostatic epithelial cell proliferation and inflammation. Phytother Res. 2012;26(2):259-264.2165660211. Villaverde N, Galvis A, Marcano A, Priestap HA, Bennett BC, Barbieri MA. Saw palmetto ethanol extract inhibits adipocyte differentiation [published online ahead of print November 23, 2012]. J Nat Med.2317931610.1007/s11418-012-0723-212. Latil A, Libon C, Templier M, Junquero D, Lantoine-Adam F, Nguyen T. Hexanic lipidosterolic extract of Serenoa repens inhibits the expression of two key inflammatory mediators, MCP-1/CCL2 and VCAM-1, in vitro. BJU Int. 2012;110(6 Pt B):E301-E307.2252055713. MacDonald R, Tacklind JW, Rutks I, Wilt TJ. Serenoa repens monotherapy for benign prostatic hyperplasia (BPH): An updated Cochrane systematic review. BJU Int. 2012;109(12):1756-1761.2255133014. Barry MJ, Meleth S, Lee JY, et al; Complementary and Alternative Medicine for Urological Symptoms (CAMUS) Study Group. Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial. JAMA. 2011;306(12):1344-1351.2195447815. Bent S, Kane C, Shinohara K, et al. Saw palmetto for benign prostatic hyperplasia. N Eng J Med. 2006;354(6):557-566.1646754316. 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;51(6):1003-1007.960964017. How to beat the post-saw palmetto blues. Despite disappointing scientific tests of saw palmetto to ease bothersome urinary symptoms, men still have self-help options. Harv Mens Health Watch. 2012;16(11):3.2276840518. Ricco J, Prasad S. The shrinking case for saw palmetto. J Fam Pract. 2012;61(7):418-420.2275489219. Spatafora S, Casarico A, Fandella A, et al for the AURO.it BPH Guidelines Committee. Evidence-based guidelines for the treatment of lower urinary tract symptoms related to uncomplicated benign prostatic hyperplasia in Italy: updated summary from AURO.it. Ther Adv Urol. 2012;4(6):279-301.2320505620. Bertaccini A, Giampaoli M, Cividini R, et al. Observational database Serenoa repens (DOSSER): overview, analysis and results. A multicentric SIUrO (Italian Society of Oncological Urology) project. Arch Ital Urol Androl. 2012;84(3):117-122.2321040221. Suter A, Saller R, Riedi E, Heinrich M. Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trial. Phytother Res. 2012; 27(2)218-226.2321040222. Iacono F, Prezioso D, Illiano E, Ruffo A, Romeo G, Amato B. Observational study: daily treatment with a new compound "Tradamixina" plus Serenoa repens for two months improved the lower urinary tract symptoms. BMC Surg. 2012;12(suppl 1):S22.2317365023. Tuncel A, Ener K, Han O, et al. Effects of short-term dutasteride and Serenoa repens on perioperative bleeding and microvessel density in patients undergoing transurethral resection of the prostate. Scand J Urol Nephrol. 2009;43(5):377-382.1992198324. Kane CJ, Raheem OA, Bent S, Avins AL. What do I tell patients about saw palmetto for benign prostatic hyperplasia? Urol Clin North Am. 2011;38(3):261-277.2179838825. Wadsworth TL, Worstell TR, Greenberg NM, Roselli CE. Effects of dietary saw palmetto on the prostate of transgenic adenocarcinoma of the mouse prostate model (TRAMP). Prostate. 2007;67(6):661-673.1734274326. Vela-Navarrete R, Escribano-Burgos M, Farré AL, García-Cardoso J, Manzarbeitia F, Carrasco C. Serenoa repens treatment modifies Bax/Bcl-2 index expression and caspase-3 activity in prostatic tissue from patients with benign prostatic hyperplasia. J Urol. 2005;173(2):507-510.1564323027. Baron A, Mancini M, Caldwell E, Cabrelle A, Bernardi P, Pagano F. Serenoa repens extract targets mitochondria and activates the intrinsic apoptotic pathway in human prostate cancer cells. BJU Int. 2009;103(9):1275-1283.1915446828. Scholtysek C, Krukiewicz AA, Alonso JL, Sharma KP, Sharma PC, Goldmann WH. Characterizing components of the Saw Palmetto Berry Extract (SPBE) on prostate cancer cell growth and traction. Biochem Biophys Res Commun. 2009;379(3):795-798.1905920529. Cassileth B. Integrative oncology. Saw palmetto. Oncology (Williston Park). 2010;24(8):766.2071825930. Miroddi M, Carni A, Mannucci C, Moleti M, Navarra M, Calapai G. Hot flashes in a young girl: a wake-up call concerning Serenoa repens use in children. Pediatrics. 2012;130(5):e1374-e1376.2302716431. Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs. 2009;69(13):1777-1798.1971933332. Ulbricht C, Basch E, Bent S, et al. Evidence-based systematic review of saw palmetto by the Natural Standard Research Collaboration. J Soc Integr Oncol. 2006;4(4):170-186.1702292533. Posadzki P, Watson L, Ernst E. Herb-drug interactions: an overview of systematic reviews. Br J Clin Pharmacol. 2013;75(3):603-618.2267073134. Chua T, Simpson JS, Ventura S. Ethanol extracts of saw palmetto contain the indirectly acting sympathomimetic: tyramine. Prostate. 2011;71(1):71-80.2063232035. Agbabiaka TB, Pittler MH, Wider B, Ernst E. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf. 2009;32(8):637-647.1959152936. Avins AL, Bent S, Staccone S, et al. A detailed safety assessment of a saw palmetto extract. Complement Ther Med. 2008;16(3):147-154.1853432737. Avins AL, Lee JY, Meyers CM, Barry MJ; CAMUS Study Group. Safety and toxicity of saw palmetto in the CAMUS trial [published online ahead of print October 9, 2012]. J Urol.2306363310.1016/j.juro.2012.10.00238. Yue QY, Jansson K. Herbal drug curbicin and anticoagulant effect with and without warfarin: possibly related to the vitamin E component. J Am Geriatr Soc. 2001;49(6):838.1145413239. Beckert BW, Concannon MJ, Henry SL, Smith DS, Puckett CL. The effect of herbal medicines on platelet function: an in vivo experiment and review of the literature. Plast Reconstr Surg. 2007;120(7):2044-2050.1809077340. 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(2):167-169.1148906741. Villanueva S, González J. Coagulopathy induced by saw palmetto: a case report. Bol Asoc Med P R. 2009;101(3):48-50.2012098642. Bruminhent J, Carrera P, Li Z, Amankona R, Roberts IM. Acute pancreatitis with saw palmetto use: a case report. J Med Case Rep. 2011;5:414.2186754543. Wargo KA, Allman E, Ibrahim F. A possible case of saw palmetto-induced pancreatitis. South Med J. 2010;103(7):683-685.2053105744. Hanaka M, Yoshii C, Yatera K, et al. A case of rhabdomyolysis caused by saw palmetto of healthy foods. J UOEH. 2012;34(2):193-199.2276842645. Lapi F, Gallo E, Giocaliere E, et al. Acute liver damage due to Serenoa repens: a case report. Br J Clin Pharmacol. 2010;69(5):558-560.2057309346. Yeu E, Grostern R. Saw palmetto and intraoperative floppy-iris syndrome. J Cataract Refract Surg. 2007;33(5):927-928.1746687747. Trinachartvanit W, Francis BM, Rayburn AL. Saw palmetto extract induces nuclear heterogeneity in mice. Environ Toxicol Pharmacol. 2009;27(1):149-154.2178393348. Zava DT, Dollbaum CM and Blen M. Estrogen and progestin bioactivity of foods, herbs, and spices. Proc Soc Exp Biol Med. 1998;217(3):369-378.949235049. Yue QY, Jansson K. Herbal drug curbicin and anticoagulant effect with and without warfarin: possibly related to the vitamin E component. J Am Geriatr Soc. 2001;49(6):838.1145413250. Cheema P, El-Mefty O, Jazieh AR. Intraoperative haemorrhage associated with the use of extract of saw palmetto herg: a case report and review of literature. J Intern Med. 2001;250(2):167-169.1148906751. Agbabiaka TB, Pittler MH, Wider B, et al. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf. 2009;32(8):637-647.1959152952. Beckert BW, Concannon MJ, Henry SL, et al. The effect of herbal medicines on platelet function: an in vivo experiment and review of the literature. Plast Reconstr Surg. 2007;120(7):2044-2050.1809077353. Yale SH, Glurich I. Analysis of the inhibitory potential of Ginkgo biloba, Echinacea purpurea, and Serenoa repens on the metabolic activity of cytochrome P450 3A4, 2D6, and 2C9. J Altern Complement Med. 2005;11(3):433-439.1599222654. Markowitz JS, Donovan JL, Devane CL, et al. Multiple doses of saw palmetto (Serenoa repens) did not alter cytochrome P450 2D6 and 3A4 activity in normal volunteers. Clin Pharmacol Ther. 2003;74(6):536-542.1599222655. McVary KT, Roehrborn CG, Avins AL, et al. Update on AUA guideline on the management of benign prostatic hyperplasia. J Urol. 2011;185(5):1793-1803.2142012456. Oelke M, Bachmann A, Descazeaud A, et al. EAU guidelines on the treatment and follow-up of non-neurogenic male lower urinary tract symptoms including benign prostatic obstruction. Eur Urol. 2013;64(1):118-140.2354133857. Coulson S, Rao A, Beck SL, Steels E, Gramotnev H, Vitetta L.. A phase II randomised double-blind placebo-controlled clinical trial investigating the efficacy and safety of ProstateEZE Max: a herbal medicine preparation for the management of symptoms of benign prostatic hypertrophy. Complement Ther Med. 2013;21(3):172-179.2364294858. Morgia G, Russo GI, Voce S, et al. Serenoa repens, lycopene and selenium versus tamsulosin for the treatment of LUTS/BPH. An Italian multicenter double-blinded randomized study between single or combination therapy (PROCOMB trial). Prostate. 2014;74(15):1471-1480.2515473959. Tacklind J, MacDonald R, Rutks I, Stanke JU, Wilt TJ. Serenoa repens for benign prostatic hyperplasia. Cochrane Database of Syst Rev. 2012;12:CD001423.2323558160. Page RL 2nd, O'Bryant CL, Cheng D, et al; American Heart Association Clinical Pharmacology and Heart Failure and Transplantation Committees of the Council on Clinical Cardiology; Council on Cardiovascular Surgery and Anesthesia; Council on Cardiovascular and Stroke Nursing; and Council on Quality of Care and Outcomes Research. Drugs That May Cause or Exacerbate Heart Failure: A Scientific Statement From the American Heart Association. Circulation. 2016;134(6):e32-69.2740098461. Gafner S, Baggett S. Botanical adulterants bulletin on saw palmetto (Serenoa repens) adulteration. American Botanical Council-Botanical Adulterants Bulletin. http://abc.herbalgram.org/site/MessageViewer?em_id=40130.0&dlv_id=92092. Published February 2017. Accessed February 12, 2017.
This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.
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