What does saw palmetto do?
Dec 17, 2020

What is saw palmetto?

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.

Its effects on DHT production have also led to saw palmetto being used for benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) in men. Some studies have shown positive results, but larger and more well-designed studies have brought its efficacy into question.

What is saw palmetto used for?

Uses & Effectiveness

Possibly Effective for

A type of prostate surgery (transurethral resection of the prostate or TURP). Research shows that taking 320 mg of saw palmetto daily for 2 months before prostate surgery can reduce the time spent in surgery, blood loss, the development of problems during surgery, and the total time spent in the hospital. However, one small study found that taking 160 mg of saw palmetto per day for 5 weeks before surgery does not lower the risk of problems during surgery.

Possibly Ineffective for

Enlarged prostate (benign prostatic hyperplasia or BPH). While conflicting results exist, higher quality and more reliable research shows that saw palmetto has little or no benefit for reducing symptoms in men with BPH. Saw palmetto doesn't seem to reduce the need to go to the bathroom at night or painful urination.

Insufficient Evidence for

Male pattern baldness (androgenic alopecia). The effects of saw palmetto in people with male pattern baldness are conflicting. Early research shows that applying saw palmetto to the scalp may increase hair growth. Also, a combination of saw palmetto and beta-sitosterol taken by mouth may improve the amount and quality of hair in men with male pattern baldness. But it doesn't work as well as the drug finasteride.

A condition that causes persistent pelvic pain, urinary problems, and sexual problems (chronic prostatitis and chronic pelvic pain syndrome). The results of research on the effects of saw palmetto are conflicting. Some research suggests it might work. But other research does not.

Prostate cancer. Taking saw palmetto doesn't seem to be linked with a reduced risk of prostate cancer. Also, taking saw palmetto during radiation for early prostate cancer doesn't seem to improve symptoms of the disease.

Swelling (inflammation) of the prostate due to infection. Some research shows that taking saw palmetto along with antibiotics might improve symptoms of prostate swelling due to infection.



Chronic bronchitis.

Common cold.


Male pattern hair growth in women (hirsutism).



Increasing sexual desire in healthy people.

Sexual problems that prevent satisfaction during sexual activity.

Sore throat.

Other conditions.

More evidence is needed to rate the effectiveness of saw palmetto for these uses.

saw palmetto

People use saw palmetto to treat the symptoms of an enlarged prostate (BPH).

Most studies show that taking saw palmetto doesn't help symptoms of BPH any more than taking a placebo . footnote1

A review of studies done on saw palmetto showed that men who took saw palmetto had some improvement in nighttime urination. But when only the best studies were included in the review, men who took saw palmetto had no difference in symptoms, urine flow, or nighttime urination compared with men who took a placebo. footnote2

In another study, men who took even higher doses of saw palmetto had no difference in BPH symptoms, urine flow, or nighttime urination compared with men who took a placebo. footnote3

Is saw palmetto safe?

Few problems have been reported among men taking saw palmetto. But some men may experience stomach problems. Saw palmetto is less likely than finasteride to cause difficulty in getting an erection.

Men who have problems urinating should see a doctor to rule out prostate cancer. Prostate cancer is treatable, but treatment is most successful when you find and treat the cancer as early as possible.

If you intend to use saw palmetto to treat symptoms of BPH, look for a product that has a fat-soluble extract of the saw palmetto berry. The active compound does not dissolve well in water. So drinking a tea or water extract made from saw palmetto berries is not likely to have an effect on the symptoms of BPH.

The U.S. Food and Drug Administration (FDA) does not regulate dietary supplements in the same way it regulates medicines. A dietary supplement can be sold with limited or no research on how well it works.

Always tell your doctor if you are using a dietary supplement or if you are thinking about combining a dietary supplement with your conventional medical treatment. It may not be safe to forgo your conventional medical treatment and rely only on a dietary supplement.

When using dietary supplements, keep in mind the following:

Like conventional medicines, dietary supplements may cause side effects, trigger allergic reactions, or interact with prescription and nonprescription medicines or other supplements you might be taking. A side effect or interaction with another medicine or supplement may make other health conditions worse.

Dietary supplements may not be standardized in their manufacturing. This means that how well they work or any side effects they cause may differ among brands or even within different lots of the same brand. The form you buy in health food or grocery stores may not be the same as the form used in research.

The long-term effects of most dietary supplements, other than vitamins and minerals, are not known. Many dietary supplements are not used long-term.

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Health Benefits

In alternative medicine, saw palmetto is said to aid in the treatment of health problems including asthma, benign prostatic hypertrophy (BPH), chronic pelvic pain syndrome, colds, coughs, migraine, prostate cancer, and sore throat.

Saw palmetto is also thought to increase libido, as well as alleviate stress.

Scientific studies have provided limited support for some of these benefits.


One of the most common uses of saw palmetto is the treatment of BPH, a condition marked by enlargement of the prostate. BPH is not considered a serious health issue, but it often causes symptoms such as the increased need to urinate. It also may lead to urinary tract infections and other complications.

Several small studies have shown that saw palmetto may help relieve BPH symptoms. However, a report published in the Cochrane Database of Systematic Reviews in 2012 found that saw palmetto may be ineffective in treating urinary symptoms associated with BPH.

For this report, researchers analyzed 32 previously published clinical trials with a total of 5,666 participants. Their analysis determined that the use of saw palmetto did not improve urinary flow measures or prostate size in men with BPH-related lower urinary tract symptoms.

Hair Loss

Saw palmetto is said to inhibit the activity of 5-alpha-reductase, an enzyme involved in converting testosterone to a hormone called dihydrotestosterone. Dihydrotestosterone appears to play a key role in the development of androgenic alopecia, a condition more commonly known as male-pattern hair loss.

While research on saw palmetto's effects against hair loss is limited, there's some evidence that it may help treat androgenetic alopecia.

In a pilot study published in the Journal of Alternative and Complementary Medicine in 2002, for instance, a group of males with mild to moderate androgenetic alopecia showed a "highly positive response" to treatment with saw palmetto and beta-sitosterol. The study's authors partly attributed this finding to saw palmetto's possibly blocking the activity of 5-alpha reductase.

Other Benefits

Emerging research suggests that saw palmetto shows promise in the treatment of certain other health conditions.

For example, a small study published in the Swiss journal Urologia Internationalis in 2010 found that saw palmetto may be of some benefit to patients with chronic prostatitis/chronic pelvic pain syndrome.

In the study, 102 patients with chronic prostatitis/chronic pelvic pain syndrome were split into two groups: the first group received a combination of saw palmetto, selenium, and lycopene; the second group received saw palmetto alone. After eight weeks of treatment, both groups showed a significant improvement in symptoms. 

There's also some evidence that taking saw palmetto prior to undergoing prostate surgery may reduce the time spent in surgery (as well as blood loss, the development of problems during surgery, and total time spent in the hospital). 

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