What Is Saw Palmetto?

This fruit extract may decrease symptoms of enlarged prostate

Palmetto softgels, capsules, and tincture

Verywell / Anastasia Tretiak

Saw palmetto (Serenoa repens or Sabal serrulata) is a plant belonging to the palm tree family native to the southeastern United States. Historically, the Glades culture and the Seminole tribes in southern Florida used the fruit of saw palmetto to treat particular urinary tract and reproductive conditions. The extract of the saw palmetto fruit contains phytosterols and flavonoids, which block the effect of androgens (natural sex steroid hormones). A test tube study suggested palmetto relieved the lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH), also known as an enlarged prostate. It did this by blocking the effects of androgens and by blocking inflammation. Popularly taken for prostate enlargement, saw palmetto is also taken for hair loss and chronic pelvic pain.

This article discusses the potential uses of saw palmetto, its possible side effects, and the risks of taking this popular supplement.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. When possible, choose a supplement tested by a trusted third party, such as the United States Pharmacopeia (USP), ConsumerLab, or the National Science Foundation (NSF). However, even if supplements are third-party tested, that doesn’t mean they are safe for all or effective in general. Therefore, talk to your healthcare provider about any supplements you plan to take and check in about potential interactions with other supplements or medications.

Supplement Facts

  • Active ingredient(s): Phytosterols, flavonoids
  • Alternate name(s): Serenoa repens, American dwarf palm tree, cabbage palm, saw palmetto fruit, saw palmetto extract
  • Legal status: Over-the-counter herbal supplement (United States)
  • Suggested dose: For lower urinary tract symptoms associated with BPH, the standard dose for clinical trials is 320 milligrams (mg) per day (160 milligrams (mg) soft capsule twice daily by mouth).
  • Safety considerations: Hormone-sensitive cancer, pregnancy, breastfeeding, prescription drugs (e.g., hormone-containing drugs, blood thinners). Stomach discomfort.

Uses of Saw Palmetto

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Saw palmetto is perhaps best known for its use in treating prostate problems. This includes BPH and prostatitis (prostate inflammation),

There's limited evidence to support these claims.

Symptoms of Enlarged Prostate

One of the most common uses of saw palmetto is the treatment of BPH, also known as an enlarged prostate. Benign prostatic hyperplasia is not considered a severe health issue, but it can cause significant symptoms, such as the increased need to urinate and urinary leakage. It can also increase the risk of urinary tract infections.

In a 24-week study of 354 people designated male at birth ages 50–70 years with lower urinary tract symptoms (LUTS) associated with BPH, the ingestion of Serenoa repens extract improved such urinary symptoms compared to a placebo.

This finding contrasted with previous results from a systematic review that reported that Serenoa repens showed no improvement of urinary symptoms in people designated male at birth with BPH compared to a placebo.

A meta-analysis (a collection of studies) evaluating four randomized, double-blind, controlled trials involving 1,080 people with BPH reported Serenoa repens taken daily for six months appeared to improve urinary flow, similar to the effect of Flomax (tamsulosin) (although there was no improvement in prostate size—unlike with tamsulosin).

Further research is necessary.

Hair Loss

Lab studies have shown that saw palmetto can block the action of 5-alpha-reductase, an enzyme that converts testosterone to a hormone called dihydrotestosterone (a more potent form of testosterone). Dihydrotestosterone appears to play a role in developing androgenetic alopecia (AGA), more commonly known as male-pattern hair loss or baldness.

Although topical Rogaine (minoxidil) and oral finasteride are two FDA-approved drugs that treat male-pattern baldness, their unfavorable side effect profile may make supplements, such as saw palmetto, seem like an attractive option.

A two-year study consisting of 100 people designated male at birth and between 20 and 40 years of age with mild to moderate AGA showed that taking Serenoa repens 320 mg per day by mouth helped stabilize hair loss. Still, only at the top of the head, finasteride 1 mg per day by mouth was more effective because it also functioned well in the frontal region (forelock or central forelock) of the hair. Furthermore, the study suggested that Serenoa repens could be an alternative for people with mild to moderate AGA who cannot use finasteride or other topical therapies. However, more studies are necessary to confirm the efficacy of Serenoa repens and its mechanism.

In a 24-week study of 50 people designated male at birth and between 20 and 50 years old with mild to moderate hair loss, the daily topical application of 3.3 milliliters (mL) of concentrated serum-containing Serenoa repens to the thinning areas on the scalp for the first four weeks and two milliliters of lotion-containing Serenoa repens to the whole scalp throughout the study period resulted in a significant increase in hair count at the 12th week.

Notably, the positive gains declined in the 24th week, most likely due to the termination of a more concentrated Serenoa repens-containing serum after only four weeks. It is important to note that the study was limited in that it did not have a control group and that the length of the study (duration) was only 24 weeks. Additionally, the serum and lotion used in the study contained saw palmetto, green tea extract, peony root extract, piroctone olamine, and oligopeptides. The effect of saw palmetto alone is unclear.

Chronic Pelvic Pain Syndrome/Chronic Prostatitis Symptoms

Emerging research investigated the use of saw palmetto in people with chronic pelvic pain syndrome (CPPS). Chronic pelvic pain syndrome is defined as pain in the pelvic area (the area below the belly button and between the hips) that lasts over six months and is severe enough to limit functioning. Chronic prostatitis/chronic pelvic pain syndrome, or CP/CPPS, is a syndrome defined by the chronic pelvic pain that is often associated with lower urinary tract symptoms (LUTS). Moreover, the National Institutes of Health (NIH) defines CP/CPPS as a syndrome without an infection.

In a multicenter, randomized, double-blind, placebo-controlled trial of 221 people designated male at birth and between 18 and 50 years old with CP/CPPS, the intake of a 160 mg soft capsule of Serenoa repens by mouth twice daily for 12 weeks showed significant improvement of pain relief and urinary symptoms compared with a placebo group. The study was limited because it did not distinguish between people with or without inflammatory CP/CPPS.

Although one study in a meta-analysis (collection of studies) showed that Serenoa repens was more effective than a placebo in treating CP/CPPS, other studies showed inconsistent results. Further relevant studies are necessary to confirm the result.

Other Uses

In addition to the potential health benefits listed above, other traditional and unproven uses of saw palmetto include the following:

  • Colds and coughs
  • Sore throat
  • Asthma
  • Chronic bronchitis
  • Migraine headache
  • Fluid retention (when taken as a diuretic)
  • Relaxation (when taken as a sedative)

What Are the Side Effects of Saw Palmetto?

Despite its therapeutic potential, saw palmetto may have potential side effects. Let’s discuss the possible common and severe side effects.

Common Side Effects

Common side effects include but may not be limited to the following:

Severe Side Effects

No severe side effects were reported in studies evaluating the efficacy and safety of Serenoa repens in people with LUTS/BPH and CP/CPPS.

Stop taking saw palmetto if you experience an allergic reaction such as hives, difficulty breathing, or swelling of the face, lips, tongue, or throat.


Precautions should be taken when considering the use of saw palmetto in the following groups:

  • Hormone-sensitive cancer: Saw palmetto can theoretically influence sex hormone levels, including estrogen and testosterone. Because of this, people with hormone-sensitive cancers (including breast and prostate cancer) should consult their oncologist before taking saw palmetto. Some people designated male at birth have also reported erectile dysfunction, breast tenderness, gynecomastia (breast enlargement), and a loss of libido (sex drive) while taking saw palmetto.
  • Pregnancy or breastfeeding: Saw palmetto may be unsafe to take when pregnant or breastfeeding. Please do not start taking saw palmetto without first consulting with your healthcare provider.
  • Children: Because the safety of saw palmetto has been studied primarily in people designated male at birth with BPH, little is known about its safety for children.

Dosage: How Much Saw Palmetto Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.

The standard dose for clinical trials studying the efficacy of saw palmetto in treating BPH, male-pattern baldness, and CP/CPPS is a 320 mg soft capsule by mouth daily. 

Please speak to your healthcare provider before taking supplements for medical reasons because there may be situations in which they pose more harm than good.

Saw palmetto capsules
Verywell / Anastasia Tretiak

What Happens if I Take Too Much Saw Palmetto?

A trial conducted in 369 people designated male at birth taking saw palmetto extract in an escalating manner at doses of 320, 640, and 960 mg at six-month intervals over 18 months showed no evidence of toxicity. Furthermore, no differences were observed between the groups in serious or non-serious adverse events.

However, as a general rule, never take more than the recommended dose on the product label.


  • Saw palmetto appears to pose a limited risk for drug interactions in humans. However, caution should be taken if you take the following prescription drugs:
  • 5-alpha-reductase inhibitors: Some studies have evaluated the combined effectiveness of saw palmetto and other medicinal plants, alpha-blockers (e.g., Flomax or tamsulosin), and 5-alpha-reductase inhibitors (Proscar or finasteride). However, because saw palmetto acts as a 5-alpha reductase inhibitor, taking saw palmetto with a prescription drug that inhibits 5-alpha reductase, such as Proscar (finasteride), can theoretically cause an additive effect and increase your risk of side effects.
  • Hormone replacement therapy/birth control pills: Because saw palmetto contains phytosterols, it acts as an anti-androgen. Saw palmetto can theoretically block the action or decrease the effectiveness of hormone replacement therapy, such as testosterone, an androgen hormone. Additionally, taking saw palmetto with estrogen pills might decrease the effectiveness of estrogen.

Blood thinners: Although the evidence is inconclusive, saw palmetto may increase bleeding time based on several case reports. It's essential to consult with your healthcare provider before starting saw palmetto if you take the following medications: Coumadin (warfarin), Plavix (clopidogrel), and non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, Advil (ibuprofen), and Aleve (naproxen).

How to Store Saw Palmetto

Store saw palmetto supplements in a cool and dry place, away from direct sunlight. Discard as indicated by their packaging.

Similar Supplements

The following are supplements that may share effects similar to those of saw palmetto:

An experimental model showed that the combination of saw palmetto, selenium, and lycopene is more effective than saw palmetto alone in reducing the prostate inflammatory response. However, the effects of saw palmetto alone are unclear. And whether this translates to a real-life setting still requires some clarification.

Frequently Asked Questions

  • What are the side effects of saw palmetto?

    The most common side effect reported in clinical studies is mild stomach discomfort. A meta-analysis (a collection of studies) showed that the saw palmetto group had a lower incidence of sexual dysfunction than a group using tamsulosin. No severe side effects were noted in clinical studies evaluating the safety of saw palmetto.

  • Does saw palmetto affect my prostate-specific antigen (PSA) level?

    Prostate-specific antigen, or PSA, is a protein produced by both healthy and cancerous cells. An elevated level of PSA in the blood is often associated with an increased risk for prostate cancer, although other non-cancerous conditions can also affect PSA levels. Several studies indicated that saw palmetto supplementation failed to cause changes to PSA concentrations when compared with a placebo, finasteride, or tamsulosin. Moreover, the National Center for Complementary and Integrative Health states that saw palmetto does not appear to affect readings of PSA levels, even when taken in higher-than-usual amounts.

  • Can people designated female at birth take saw palmetto?

    Saw palmetto has been taken predominantly by people designated male at birth. However, a study found that a 320 mg capsule of saw palmetto taken by mouth once daily for 12 weeks reduced the symptoms of daytime and nighttime urinary frequency in people designated female at birth. Of note, people who are pregnant, breastfeeding, or taking hormone-containing drugs should likely avoid taking saw palmetto.

Sources of Saw Palmetto and What to Look For

Saw palmetto supplements typically contain extracts of the plant's fruit. You can purchase saw palmetto supplements online and in many natural food stores, drugstores, and stores specializing in herbal products.

Because nutritional supplements are not stringently regulated by the FDA, their quality can vary from one brand to the next.

If you choose to buy this or any supplement, read the supplement facts label because it contains valuable information, including the amount of active and inactive ingredients per serving (including fillers and binders to which you may be allergic).

Opt for supplements certified by the U.S. Pharmacopeia (USP), ConsumerLab, or the National Science Foundation. Certification does not guarantee the product's safety or effectiveness but provides assurance that the product was manufactured correctly, contains the ingredients listed on the product label, and does not contain harmful contaminants.

It is essential to carefully read a supplement's ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

Saw Palmetto Supplements

Saw palmetto is available as a capsule, soft gel, liquid extract, tincture, powder, dried berry, and tea.

The extract obtained from the berries of saw palmetto is rich in fatty acids, which are believed to be responsible for the inhibition of 5-alpha-reductase.

Because fatty acids are insoluble in water, it would follow that consuming saw palmetto in a tea form may not be as effective. Moreover, it has been found that liquid saw palmetto supplements contain the highest concentrations of fatty acid and phytosterol, followed by powder, dried berry, and tincture supplements. Such findings suggest that the liquid form (that is, the content in gel capsules) of saw palmetto may be the best choice if you want to take a saw palmetto supplement with the highest concentrations of bioactive components or active ingredients.

Saw palmetto is also included in topical (on the skin) serums for hair loss. However, such products have often been combined with other ingredients, such as pumpkin seed oil and rosemary essential oil. The effects of saw palmetto alone are unclear.


Saw palmetto is a plant belonging to the palm tree family. Its fruit extract has been studied with some evidence showing the role of saw palmetto in improving symptoms associated with enlarged prostate, reducing hair loss, and improving symptoms of CP/CPPS. 

In general, saw palmetto supplements are well tolerated but may cause stomach discomfort in some people. Saw palmetto should not be taken by children, during pregnancy or breastfeeding, or by those with hormone-sensitive cancers. You should also avoid it if you take hormone replacement therapy, birth control pills, or blood thinners.

36 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Center for Complementary and Integrative Health. Saw palmetto.

  2. Kwon Y. Use of saw palmetto (Serenoa repens) extract for benign prostatic hyperplasia. Food Sci Biotechnol. 2019;28(6):1599-1606. Published 2019 Apr 17. doi:10.1007/s10068-019-00605-9

  3. Zgonc Škulj A, Poljšak N, Kočevar Glavač N, Kreft S. Herbal preparations for the treatment of hair loss. Arch Dermatol Res. 2020;312(6):395-406. doi:10.1007/s00403-019-02003-x

  4. Cai T, Cui Y, Yu S, et al. Comparison of Serenoa repens with tamsulosin in the treatment of benign prostatic hyperplasia: a systematic review and meta-analysis. Am J Mens Health. Mar-Apr 2020;4(2):1557988320905407. doi:10.1177/1557988320905407

  5. Zhang K, Guo RQ, Chen SW, et al. The efficacy and safety of Serenoa repens extract for the treatment of patients with chronic prostatitis/chronic pelvic pain syndrome: a multicenter, randomized, double-blind, placebo-controlled trial. World J Urol. 2021;39(9):3489-3495. doi:10.1007/s00345-020-03577-2

  6. Rossi A, Mari E, Scarnò M, et al. Comparative effectiveness and finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study. Int J Immunopathol Pharmacol. 2012;25(4):1167-1173. doi:10.1177/039463201202500435

  7. Ye Z, Huang J, Zhou L, et al. Efficacy and safety of Serenoa repens extract among patients with benign prostatic hyperplasia in China: a multicenter, randomized, double-blind, placebo-controlled trial. Urology. 2019;129:172-179. doi:10.1016/j.urology.2019.02.030

  8. Csikós E, Horváth A, Ács K, et al. Treatment of benign prostatic hyperplasia by natural drugs. Molecules. 2021;26(23):7141. Published 2021 Nov 25. doi:10.3390/molecules26237141

  9. Cicero AFG, Allkanjari O, Busetto GM, et al. Nutraceutical treatment and prevention of benign prostatic hyperplasia and prostate cancer. Arch Ital Urol Androl. 2019;91(3):10.4081/aiua.2019.3.139. Published 2019 Oct 2. doi:10.4081/aiua.2019.3.139

  10. Agbabiaka TB, Pittler MH, Wider B, Ernst E. Serenoa repens (saw palmetto): a systematic review of adverse events. Drug Saf. 2009;32(8):637-47. doi:10.2165/00002018-200932080-00003

  11. Choi JB, Min SK. Complicated urinary tract infection in patients with benign prostatic hyperplasia. J Infect Chemother. 2021;27(9):1284-1287. doi:10.1016/j.jiac.2021.06.006

  12. Tacklind J, Macdonald R, Rutks I, et al. Serenoa repens for benign prostatic hyperplasia. Cochrane Database Syst Rev. 2012 Dec 12;12:CD001423. doi:10.1002/14651858.CD001423.pub3

  13. Dhariwala MY, Ravikumar P. An overview of herbal alternatives in androgenetic alopecia. J Cosmet Dermatol. 2019;18(4):966-975. doi:10.1111/jocd.12930

  14. Ashique S, Sandhu NK, Haque SN, Koley K. A systemic review on topical marketed formulations, natural products, and oral supplements to prevent androgenic alopecia: a review. Nat Prod Bioprospect. 2020;10(6):345-365. doi:10.1007/s13659-020-00267-9

  15. Wessagowit V, Tangjaturonrusamee C, Kootiratrakarn T, et al. Treatment of male androgenetic alopecia with topical products containing Serenoa repens extract. Australas J Dermatol. 2016;57(3):e76-e82. doi:10.1111/ajd.12352

  16. Grinberg K, Sela Y, Nissanholtz-Gannot R. New Insights about Chronic Pelvic Pain Syndrome (CPPS). Int J Environ Res Public Health. 2020;17(9):3005. Published 2020 Apr 26. doi:10.3390/ijerph17093005

  17. Polackwich AS, Shoskes DA. Chronic prostatitis/chronic pelvic pain syndrome: a review of evaluation and therapy. Prostate Cancer Prostatic Dis. 2016;19(2):132-138. doi:10.1038/pcan.2016.8

  18. Rees J, Abrahams M, Doble A, et al. Diagnosis and treatment of chronic bacterial prostatitis and chronic prostatitis/chronic pelvic pain syndrome: a consensus guideline. BJU Int. 2015;116(4):509-525. doi:10.1111/bju.13101

  19. Lok W, Lin T, Cao D, Wei Q. Is Serenoa repens effective for the treatment of chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS)? A systematic review and meta-analysis. Asian J Surg. 2022;45(9):1746-1747. doi:10.1016/j.asjsur.2022.01.038

  20. Wanwimolruk S, Phopin K, Prachayasittikul V. Cytochrome P450 enzyme mediated herbal drug interactions (Part 2). EXCLI J. 2014;13:869-896. Published 2014 Aug 20.

  21. Avins AL, Lee JY, Meyers CM, et al. Safety and toxicity of saw palmetto in the CAMUS trial. J Urol. 2013;189(4):1415-1420. doi:10.1016/j.juro.2012.10.002

  22. Gupta AK, Talukder M, Bamimore MA. Natural products for male androgenetic alopecia. Dermatol Ther. 2022;35(4):e15323. doi:10.1111/dth.15323

  23. Leibbrand M, Siefer S, Schön C, et al. Effects of an oil-free hydroethanolic pumpkin seed extract on symptom frequency and severity in men with benign prostatic hyperplasia: a pilot study in humans. J Med Food. 2019;22(6):551-559. doi:10.1089/jmf.2018.0106

  24. Esposito C, Santarcangelo C, Masselli R, et al. Epilobium angustifolium L. extract with high content in oenothein B on benign prostatic hyperplasia: A monocentric, randomized, double-blind, placebo-controlled clinical trial. Biomed Pharmacother. 2021;138:111414. doi:10.1016/j.biopha.2021.111414

  25. Kutwin P, Falkowski P, Łowicki R, et al. Are we sentenced to pharmacotherapy? Promising role of lycopene and vitamin A in benign urologic conditions. Nutrients. 2022;14(4):859. Published 2022 Feb 18. doi:10.3390/nu14040859

  26. Salinas-Casado J, Esteban-Fuertes M, Carballido-Rodríguez J, Cozar-Olmo JM. Review of the experience and evidence of Pygeum africanum in urological practice. Revisión sobre la experiencia y evidencias del Pygeum africanum en Urología. Actas Urol Esp (Engl Ed). 2020;44(1):9-13. doi:10.1016/j.acuro.2019.08.002

  27. Akbar Karami A, Sheikhsoleimani M, Memarzadeh MR, et al. Urtica dioica root extract on clinical and biochemical parameters in patients with benign prostatic hyperplasia, randomized controlled trial. Pak J Biol Sci. 2020;23(10):1338-1344. doi:10.3923/pjbs.2020.1338.1344

  28. Maleš Ž, Drvar DL, Duka I, Žužul K. Application of medicinal plants in several dermatovenerologica entities. Acta Pharm. 2019;69(4):525-531. doi:10.2478/acph-2019-0045

  29. Panahi Y, Taghizadeh M, Marzony ET, Sahebkar A. Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomized comparative trial. Skinmed. 2015;13(1):15-21.

  30. Völker JM, Koch N, Becker M, Klenk A. Caffeine and its pharmacological benefits in the management of androgenetic alopecia: a review. Skin Pharmacol Physiol. 2020;33(3):93-109. doi:10.1159/000508228

  31. Pumthong G, Asawanonda P, Varothai S, et al. Curcuma aeruginosa, a novel botanically derived 5α-reductase inhibitor in the treatment of male-pattern baldness: a multicenter, randomized, double-blind, placebo-controlled study. J Dermatolog Treat. 2012;23(5):385-392. doi:10.3109/09546634.2011.568470

  32. Oh GN, Son SW. Efficacy of Korean red ginseng in the treatment of alopecia areata. J Ginseng Res. 2012;36(4):391-395. doi:10.5142/jgr.2012.36.4.391

  33. Minutoli L, Bitto A, Squadrito F, et al. Serenoa repens, lycopene and selenium: a triple therapeutic approach to manage benign prostatic hyperplasia. Curr Med Chem. 2013;20(10):1306-1312. doi:10.2174/0929867311320100007

  34. Grammatikopoulou MG, Gkiouras K, Papageorgiou ST, et al. Dietary factors and supplements influencing prostate specific-antigen (PSA) concentrations in men with prostate cancer and increased cancer risk: an evidence analysis review based on randomized controlled trials. Nutrients. 2020;12(10):2985. Published 2020 Sep 29. doi:10.3390/nu12102985

  35. Yamada S, Shirai M, Ono K, Kageyama S. Beneficial effects of saw palmetto fruit extract on urinary symptoms in Japanese female subjects by a multicenter, randomized, double-blind, placebo-controlled study. Nutrients. 2022;14(6):1190. Published 2022 Mar 11. doi:10.3390/nu14061190

  36. Penugonda K, Lindshield BL. Fatty acid and phytosterol content of commercial saw palmetto supplements. Nutrients. 2013;5(9):3617-3633. Published 2013 Sep 13. doi:10.3390/nu5093617

By Trang Tran, PharmD
Trang Tran, PharmD, is a pharmacist who is passionate about integrative health. 

Originally written by Cathy Wong
Cathy Wong

Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

Learn about our editorial process