Health Benefits of Saw Palmetto

Saw palmetto (Serenoa repens) is a small palm that grows in coastal areas and in pine forests. The plant gets its name from the sawtooth-like spines that cover its stems.

Extract from saw palmetto berries has medicinal properties and is commonly taken as a dietary supplement. Saw palmetto extract (SPE) has been shown to benefit people with genitourinary conditions such as benign prostatic hyperplasia (BPH). Saw palmetto may also improve hair loss and certain symptoms of androgen deficiency, or low testosterone levels.

Here’s what you need to know about saw palmetto supplements, including potential benefits, safety, and possible side effects. 

Benefits of Saw Palmetto

Saw palmetto contains a variety of plant compounds that have medicinal properties.

For example, the saw palmetto berry, which is the fruit of the saw palmetto plant from which SPE supplements are derived, contains over 100 compounds, including fatty acids such as caprylic, lauric, and caproic acids, and sterols, including beta-sitosterol, cycloartenol, lupeol, stigmasterol, and methylcycloartenol. The health benefits of saw palmetto supplements are attributed to these active substances.

Though the exact mechanisms by which saw palmetto impacts health aren’t fully understood, it’s thought that the compounds contained within saw palmetto, including beta-sitosterol, help relax smooth muscles, reduce inflammation, and impact the effects of androgen hormones in the body. 

May Improve Urinary Symptoms in Men with BPH

Saw palmetto has been used since ancient times to treat urinary symptoms in men. In fact, saw palmetto was commonly used to urinary symptoms in Egypt as far back as the 15th century BC. 

Benign prostatic hyperplasia (BPH) is a medical condition that causes a non-cancerous enlargement of the prostate. Commonly referred to as enlarged prostate, BPH is most common in men over the age of 60.

BPH causes urinary symptoms like urinary retention, incomplete emptying of the bladder, and a weak urine stream. These symptoms are collectively known as lower urinary tract symptoms (LUTS) and can significantly impact the quality of life in men with BPH. 

Study findings suggest that saw palmetto may help reduce LUTS in men with BPH. 

A 2020 study that included 66 men with BPH and androgen deficiency, or low testosterone levels, found that men who were supplemented with 500 milligrams (mg) of saw palmetto oil enriched with beta-sitosterol per day for twelve weeks showed a significant decrease in symptoms related to BPH, such as a feeling of incomplete bladder emptying after urination and frequent urination, compared to a placebo group. The saw palmetto group also experienced significant improvements in urine flow rate and reductions in the amount of urine left in their bladder after urinating.

In Europe, Permixon, a medication containing SPE, also known as lipidosterolic extract derived from saw palmetto berries or LSESr, is approved for use as a prescription drug for the treatment of mild-to-moderate LUTS.

However, this medication isn’t available in the U.S. and SPE is currently only used as a complementary therapy in American men with BPH.

May Improve Hair Loss

Saw palmetto may be helpful for certain people struggling with hair loss, such as androgenetic alopecia (AGA). AGA is caused by genetic and environmental factors, including a sex hormone called dihydrotestosterone (DHT). Saw palmetto blocks an enzyme called 5α-reductase(5-AR), which converts testosterone into DHT, a more potent form of testosterone. Saw palmetto also increases the activity of an enzyme called 3α-hydroxysteroid-dehydrogenase, which converts DHT to a weaker substance called androstanediol.

Though androgens like DHT are needed for normal sexual development and other important functions in both men and women, high levels of DHT can overstimulate hair follicles, which leads to a shorter growth period. This causes shorter and thinner strands of hair and delayed hair growth and replacement.  

Because saw palmetto has antiandrogenic activities, it may help improve hair loss in certain populations. 

A 2020 review of seven studies found that topical saw palmetto treatments and oral supplements containing between 100 and 320 mg of saw palmetto led to an average 60% improvement in overall hair quality and a 27% improvement in total hair count among patients with AGA and telogen effluvium (TE), a type of hair loss characterized by a disruption in the normal hair growth cycle, which leads to excessive hair shedding and hair loss.

The study also found that saw palmetto treatments increased hair density and stabilized disease progression in 83.3% and 52% of the participants, respectively. 

Though these results are promising, more research is needed to confirm these potential benefits. 

May Help Reduce Symptoms Related to Androgen Deficiency  

In the same 2020 study in 66 men with BPH and androgen deficiency mentioned above, it was found that, compared to the placebo group, the men who were supplemented with 500 mg of saw palmetto oil enriched with beta-sitosterol per day for twelve weeks had significant decreases in scores of questionnaires used to assess symptoms related to androgen deficiency, including the Aging Male Symptoms (AMS) scale and the Androgen Deficiency in the Aging Male (ADAM) questionnaire, which indicates an improvement in symptoms such as mood, low energy, and low libido.

The study also found that the men treated with saw palmetto experienced a significant increase in levels of free testosterone compared to the placebo group. 

However, there’s limited evidence that saw palmetto has a positive impact on androgen deficiency and more research is needed to understand how the compounds in saw palmetto affect sex hormone levels in men and women. 

How to Take Saw Palmetto 

Most saw palmetto supplements on the market contain extracts of the dried fruit of the plant. 

Saw palmetto supplements come in several forms, such as capsules, liquids, powders, and gummies. Saw palmetto can be taken on its own and can also be found in multi-ingredient supplements with other plant extracts and herbs, such as stinging nettle and pygeum.

Saw palmetto can be taken in one daily dose or in divided doses. If you’re unsure how to take saw palmetto supplements, consult your healthcare provider for recommendations.

It’s commonly recommended to take saw palmetto supplements with meals or after meals. In the 2020 study investigating the effects of saw palmetto supplements in men with BPH and androgen deficiency, the participants received 500 mg capsules twice per, after breakfast and dinner, for 12 weeks.

Dosage

Most studies investigating the health effects of saw palmetto supplements have used doses ranging from 100 to 500 mg per day, though higher doses have been used without incident.

In a 2012 study, 357 men were supplemented with 320 mg, 640 mg, and 960 mg saw palmetto extract in an escalating manner at six-month intervals or an identical-appearing placebo, for a total of 18 months.

The researchers found no evidence of toxicity, even at doses up to three times the usual clinical dose.

Even though higher doses of saw palmetto have been used in research studies, it doesn’t mean that high doses of saw palmetto are more effective or appropriate for everyone. If you have questions regarding safe dosing of saw palmetto supplements, contact your healthcare provider for advice. 

Is Saw Palmetto Safe?

Though saw palmetto is generally considered safe, it should be avoided by certain populations. 

For example, due to a lack of safety data and saw palmetto's impact on hormones, saw palmetto supplements shouldn’t be taken during pregnancy and breastfeeding and shouldn't be given to children.

Also, because saw palmetto may increase bleeding risk, saw palmetto supplements should be stopped at least two weeks before scheduled surgeries. 

Saw palmetto may interfere with iron absorption, so it should be used with caution in those with low iron stores and iron deficiency anemia.

Lastly, because saw palmetto can impact hormone levels in the body, it’s important to consult your healthcare provider before taking saw palmetto, especially if you have a health condition such as prostate cancer or any hormone-sensitive conditions. 

Potential Drug Interactions

Saw palmetto has the potential to interact with commonly prescribed medications, including:

• Anticoagulants: Saw palmetto has blood-thinning properties, so it may potentiate the activity of anticoagulants such as Warfarin.  
• Antiplatelets: Antiplatelets, such as aspirin, prevent platelets from clumping together to form a blood clot. Saw palmetto has blood-thinning effects, so it may interact with antiplatelet medications.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): According to case reports, saw palmetto may increase the risk of side effects associated with NSAIDs.
• UGT (Uridine 5’-diphospho-glucuronosyltransferase) substrates: Medications that inhibit UGT include the antihistamine desloratadine and the cancer medication lapatinib. Saw palmetto may also inhibit UGT enzymes and can interact with UGT-inhibiting medications.
• CYP 450 substrates: Saw palmetto may interact with drugs that are metabolized by cytochrome P450 enzymes, including the blood thinner Warfarin and the blood pressure medication metoprolol.

What to Look For

When shopping for dietary supplements, it’s important to purchase products from brands that adhere to strict safety and quality standards. 

Choosing supplements from brands certified by third-party organizations like United States Pharmacopeia (USP)—a nonprofit organization that sets standards for the purity and quality of dietary supplements—is recommended by experts in the nutrition field as a way to ensure supplement safety. 

Because saw palmetto isn’t safe for everyone and has the potential to interact with commonly prescribed medications, you should not supplement with saw palmetto unless it’s recommended by a healthcare provider. 

Some people eat saw palmetto berries and make tea and homemade liquid extracts from the fresh or dried berries. Keep in mind that the active compounds found in saw palmetto berries aren’t water-soluble, so it’s recommended to take a saw palmetto supplement over making tea or water-based extracts out of saw palmetto berries.

Though you can forage for saw palmetto berries in some areas, the plant is protected in states like Florida, as it serves as an important food source and habitat for wildlife. In Florida, you must acquire a permit before foraging for saw palmetto berries.

Can You Take Too Much Saw Palmetto? 

Saw palmetto products, including saw palmetto supplements, are thought to have low toxicity. 

The 2012 study that included 357 men found that saw palmetto showed no evidence of toxicity even at doses up to three times the usual clinical dose over a period of 18 months.

However, it’s important to follow supplement dosing instructions and avoid taking high doses of saw palmetto unless recommended and monitored by a healthcare provider. 

Side Effects of Saw Palmetto 

Saw palmetto supplements aren’t linked to many adverse side effects. However, some studies have reported some side effects, including diarrhea, headache, fatigue, decreased sex drive, and rhinitis. However, the side effects reported in studies have been mild and are similar to side effects reported in placebo groups.

For example, in the 2012 study that included 357 men who were supplemented with 320 mg, 640 mg, and 960 mg saw palmetto extract in an escalating manner at six-month intervals or an identical-appearing placebo, for a total of 18 months, the incidence of side effects was similar in both groups.

Even when the men were taking the highest dose of saw palmetto, the incidence of adverse side effects was similar in the intervention group and the placebo group.  

That said, there have been documented reports of saw palmetto supplements causing significant adverse side effects, such as pancreatitis and liver damage. Because saw palmetto has the potential to cause some side effects, it’s important only to take saw palmetto under a healthcare provider's supervision.

A Quick Review

Saw palmetto supplements contain active compounds that may benefit health in several ways. Taking saw palmetto supplements may improve symptoms related to benign prostatic hyperplasia (BPH) and low testosterone levels, and may improve hair loss in certain populations, such as in those with androgenic alopecia (AGA). 

Though saw palmetto is generally considered safe and not linked to many adverse side effects, it’s not appropriate for everyone and may interact with commonly prescribed medications, like aspirin and blood thinning drugs. 

If you’re interested in taking saw palmetto, it’s recommended to consult your healthcare provider first. They can help you determine whether taking a saw palmetto supplement may be the right choice for you and recommend appropriate dosing and safe use.