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Saw Palmetto
What is it? Overview Usage Side Effects and Warnings

Saw Palmetto Overview

Written by FoundHealth.

Saw palmetto is a native plant of North America, and it is still primarily grown in the United States.

The saw palmetto tree grows only about 2 to 4 feet high, with fan-shaped serrated leaves and abundant berries. Native Americans used these berries for the treatment of various urinary problems in men, as well as for women with breast disorders. European and American physicians took up saw palmetto as a treatment for benign prostatic hyperplasia (BPH). In the 1960s, French researchers discovered that by concentrating the oils of saw palmetto berry they could maximize the herb's effectiveness.

Saw palmetto contains many biologically active chemicals. Unfortunately, we don't know which ones are the most important. We also don't really know how saw palmetto works; it appears to interact with various sex hormones, but it also has many other complex actions that could affect the prostate.

What Is the Scientific Evidence for Saw Palmetto?


The scientific evidence for the effectiveness of saw palmetto in treating prostate enlargement is inconsistent.

At least 10 double-blind studies involving a total of about 900 people have compared the benefits of saw palmetto against placebo over periods of 1 to 12 months. 1 In all but three of these studies, the herb improved urinary flow rate and most other measures of prostate disease to a greater extent than placebo. However, in the most recent and perhaps best-designed of these studies, a 1-year trial of 225 men, a saw palmetto product failed to prove more effective than placebo. 2 Furthermore, a large review of 14 trials with 5,222 men found that saw palmetto did not improve urinary symptom scores or peak urine flow compared to placebo. Subjects taking saw palmetto reported more overall symptom improvement than those taking placebo, but this result is questionable due to inconsistencies among studies. 3 A double-blind study followed 1,098 men who received either saw palmetto or the drug Proscar over a period of 6 months. 4 (Unfortunately, there was no placebo group.) The treatments were equally effective, but while Proscar lowered PSA levels and caused a slight worsening of sexual function on average, saw palmetto caused no significant side effects. Both treatments caused the prostate to shrink, but Proscar had a greater effect.

A 52-week, double-blind study of 811 men compared saw palmetto to a standard drug in another class: the alpha-blocker tamsulosin. 5 Once again, both treatments proved equally effective. However, saw palmetto caused fewer side effects than the drug. In addition, the herb caused some prostate shrinkage, while the drug caused a slight prostate enlargement.

A study involving 435 men found that the benefits of saw palmetto endure for at least 3 years. 6 However, there was no control group in this study, making the results unreliable.

A 48-week, double-blind trial of 543 men with early BPH compared combined saw palmetto and nettle root against Proscar and found equal benefits. 7 Benefits were also seen with a combination of saw palmetto and nettle root in a 24-week, placebo-controlled study of 257 men. 8 Finally, a 6-month, double-blind, placebo-controlled trial of 44 men given a saw palmetto herbal blend (containing, in addition, nettle root and pumpkin seed oil) found shrinkage in prostate tissue. 9 No significant improvement in symptoms was seen, but the authors pointed out that the study size was too small to statistically detect such improvements if they did occur.


The standard dosage of saw palmetto for the treatment of BPH is 160 mg twice a day of an extract standardized to contain 85% to 95% fatty acids and sterols. A single daily dose of 320 mg may be just as effective for this condition. 10 However, taking more than this amount does not, on average, seem to produce better results. 11 As with many other herbs, the quality of commercial saw palmetto products may vary widely. 12 For this reason, it is best to purchase a saw palmetto product that has been evaluated by an independent lab, such as Consumer Labs .


  1. Emili E, Lo Cigno M, Petrone U. Clinical trial of a new drug for treating hypertrophy of the prostate (Permixon) [in Italian]. Urologia. 1983;50:1042-1048.
  2. Bent S, Kane C, Shinohara K, Neuhaus J, Hudes ES, Goldberg H, Avins AL. Saw palmetto for benign prostatic hyperplasia. N Engl J Med. 354(6):557-66.
  3. Tacklind J, MacDonald R, Rutks I, Wilt TJ. Serenoa repens for benign prostatic hyperplasia. Cochrane Database of Systematic Reviews. 2009; CD001423.
  4. Carraro JC, Raynaud JP, Koch G, Chisholm GD, Di Silverio F, Teillac P, Da Silva FC, Cauquil J, Chopin DK, Hamdy FC, Hanus M, Hauri D, Kalinteris A, Marencak J, Perier A, Perrin P. Comparison of phytotherapy (Permixon) with finasteride in the treatment of benign prostate hyperplasia: a randomized international study of 1,098 patients. Prostate. 29(4):231-40; discussion 241-2.
  5. Debruyne F, Koch G, Boyle P, et al. Comparison of a phytotherapeutic agent (Permixon) with an alpha-blocker (Tamsulosin) in the treatment of benign prostatic hyperplasia: a one-year randomized international study. Eur Urol. 2002;41:497-507.
  6. Bach D. Medikamentose Langzeitbehandlung der BPH. Ergebnisse einer prospektiven 3-Jahres-Studie mit dem Sabalextrakt IDS 89. Urologe [B]. 1995;35:178-183.
  7. Sökeland J. Combined sabal and urtica extract compared with finasteride in men with benign prostatic hyperplasia: analysis of prostate volume and therapeutic outcome. BJU Int. 86(4):439-42.
  8. Lopatkin N, Sivkov A, Walther C, Schläfke S, Medvedev A, Avdeichuk J, Golubev G, Melnik K, Elenberger N, Engelmann U. Long-term efficacy and safety of a combination of sabal and urtica extract for lower urinary tract symptoms--a placebo-controlled, double-blind, multicenter trial. World J Urol. 23(2):139-46.
  9. 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. 163(5):1451-6.
  10. Braeckman J, Bruhwyler J, Vandekerckhove K, et al. Efficacy and safety of the extract of Serenoa repens in the treatment of benign prostatic hyperplasia: therapeutic equivalence between twice and once daily dosage forms. Phytother Res. 1997;11:558-563.
  11. Plosker GL, Brogden RN. Serenoa repens (Permixon). A review of its pharmacology and therapeutic efficacy in benign prostatic hyperplasia. Drugs Aging. 1996;9:379-395.
  12. Feifer AH, Fleshner NE, Klotz L. Analytical accuracy and reliability of commonly used nutritional supplements in prostate disease. J Urol. 168(1):150-4; discussion 154.


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