Saw Palmetto

Saw Palmetto is a fatty acid mix from Serenoa Repens that has been touted for its abilities to increase Testosterone (not effective) and suppress prostate growth (effective); may be healthy and good treatment of Benign Prostatic Hyperplasia and abnormal urine flow rates in men.

This page features 17 unique references to scientific papers.

Confused about what actually Works?
MUST GET: Supplement Stack Guides - Saving You Money & Time


In Progress

This page on Saw Palmetto is currently marked as in-progress. We are still compiling research.

You can help contribute by:

Saw Palmetto is a supplement which is derived from the fruit of the plant Serenoa Repens. The supplement (Saw Palmetto) has a caloric value, as it is a concoction of fatty acids.

The fatty acids in question have the ability to block an enzyme that converts testosterone into dihydrotestosterone (DHT), the latter of which is a more androgenic form and can cause hairloss in the genetically susceptible.

Follow this Page for updates

Confused about Supplements?
Get the Stack Guides

Also Known As

Serenoa Repens

Things to Note

  • Saw Palmetto is primarily fatty acids, and should be taken with food.

A 160 to 320mg a day of a Saw Palmetto extract containing 80-90% liposterolic (active) compounds is typically used.

Table of Contents:

Edit1. Sources and Composition

Saw palmetto extract comes from the berries of the American Serenoa Repens, a dwarf palm tree. The extracts have traditionally been used to increase sperm motility and libido, to increase breast size, and sometimes as a diuretic.[1]

As a plant, Saw Palmetto contains:

  • Primarily saturated and unsaturated fatty acids; most (84%) in free fatty acid form and a small amount (>10%) in esterified form.[2]

  • A small amount (2%) of phytosterols, aliphatic alcohols, and polypyrenic compounds also exist.[2][3]

The composition of free fatty acids in Saw Palmetto include lauric acid, myristic acid, linoleic acid, palmitic acid, oleic acid. Lauric and Oleic both appear to be the most prominent fatty acids in Saw Palmetto (around 15% each) and have inhibitory effects on 5alpha-reductase.[2][4]

There seems to be wide variance in total fatty acid content of Saw Palmetto supplements, with the fatty acid content ranging from 40.7% to 80.7%, methyl and ethyl esters ranging from 1.5-16.7%, and glycerides ranging from 6.8-52.2%.[5] The variance seen is due to processing and sources of Serenoa Repens.[6]

Edit2. Usage in Benign Prostate Hyperplasia (BPH)

2.1. Overall

Saw Palmetto alleviates Prostate Hyperplasia by both traditional routes, the androgenic route via inhibiting the 5-alpha reductase enzyme and the adrenergic route by acting as an alpha-1 adrenergic antagonist. The latter route appears to be more effective.[7]

2.2. Androgenic interactions

Benign Prostate Hyperplasia (or Hypertrophy; interchangeable terms in this regard) is a multiplication of cells in the prostate which creates nodules that push into and compress the urinary tract, causing pain or complications in urination.

It has successfully been used in a number of trials to treat BPH.[8][1] It also increases urine flow and decreases nocturia.[9][10]

The mechanisms by which Saw Palmetto acts is via inhibition of both type I and type II isozymes of the 5alpha-reductase enzyme.[11][2] This lowers levels of dihydrotestosterone (DHT) by inhibiting testosterone's conversion into DHT, and appears to be via lauric and oleic acid.[2]

2.3. Adrenergic interactions

Saw Palmetto has been found in vitro to directly inhibit prostatic alpha-1 adrenoreceptors in a non-competitive manner.[12] Saw Palmetto also seems to suppress testosterone-induced upregulation of alpha-1 adrenoreceptors in the prostate.[3]

Edit3. Safety, Toxicity, and Adverse Effects/Interactions

Saw palmetto contains tannic acids, which bind to iron and reduce bioavailability.[13] Minor sexual dysfunction has also been reported, possibly through pro-estrogenic effects. Beyond that, side-effects are not discernable from placebo.[14]

Two case-reports have repoted pancreatitis from Saw Palmetto.[15][16] In one incidence liver damage was reported.[17]


  1. Ernst E. The risk-benefit profile of commonly used herbal therapies: Ginkgo, St. John's Wort, Ginseng, Echinacea, Saw Palmetto, and Kava. Ann Intern Med. (2002)
  2. Abe M, et al. Isolation and pharmacological characterization of fatty acids from saw palmetto extract. Anal Sci. (2009)
  3. Pharmacological effects of saw palmetto extract in the lower urinary tract
  4. Abe M, et al. Pharmacologically relevant receptor binding characteristics and 5alpha-reductase inhibitory activity of free Fatty acids contained in saw palmetto extract. Biol Pharm Bull. (2009)
  5. Habib FK, Wyllie MG. Not all brands are created equal: a comparison of selected components of different brands of Serenoa repens extract. Prostate Cancer Prostatic Dis. (2004)
  6. Levin RM, Das AK. A scientific basis for the therapeutic effects of Pygeum africanum and Serenoa repens. Urol Res. (2000)
  7. Lepor H, et al. The efficacy of terazosin, finasteride, or both in benign prostatic hyperplasia. Veterans Affairs Cooperative Studies Benign Prostatic Hyperplasia Study Group. N Engl J Med. (1996)
  8. A double-blind trial of an extract of the plant Serenoa repens in benign prostatic hyperplasia
  9. Wilt TJ, et al. Phytotherapy for benign prostatic hyperplasia. Public Health Nutr. (2000)
  10. Sultan C, et al. Inhibition of androgen metabolism and binding by a liposterolic extract of "Serenoa repens B" in human foreskin fibroblasts. J Steroid Biochem. (1984)
  11. Iehlé C, et al. Human prostatic steroid 5 alpha-reductase isoforms--a comparative study of selective inhibitors. J Steroid Biochem Mol Biol. (1995)
  12. Goepel M, et al. Saw palmetto extracts potently and noncompetitively inhibit human alpha1-adrenoceptors in vitro. Prostate. (1999)
  13. Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med. (1998)
  14. Agbabiaka TB, et al. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf. (2009)
  15. Jibrin I, et al. Saw palmetto-induced pancreatitis. South Med J. (2006)
  16. Wargo KA, Allman E, Ibrahim F. A possible case of saw palmetto-induced pancreatitis. South Med J. (2010)
  17. Lapi F, et al. Acute liver damage due to Serenoa repens: a case report. Br J Clin Pharmacol. (2010)

(Common misspellings for Saw Palmetto include paletto, palmeto, pametto, pameto)

(Common phrases used by users for this page include saw supplements composition, saw palmetto oil lauric acid, recommended dosage of saw palmetto extract, nutritional facts saw palmetto, nutrition facts of sawpalmatto, effectiveness of saw palmetto brands)

(Users who contributed to this page include cogniquity, , )