Overview

Saw palmetto is a plant called Serenoa repens. Dietary supplements that contain the berries from saw palmetto are available in many different forms, including liquids, capsules, and tablets. People take saw palmetto for various reasons, although its benefits are not well defined. Common side effects may include diarrhea, dizziness, headache, tiredness, or reduced sex drive. Before taking saw palmetto, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is saw palmetto used for?

Saw palmetto (Serenoa repens) is used for various reasons. However, the benefits of saw palmetto are not well defined. Some common reasons that people use saw palmetto include the following.

• Enlarged prostate (benign prostatic hyperplasia, or BPH)
• Male pattern hair loss

Note: The FDA has not reviewed saw palmetto for safety and effectiveness. Learn more about dietary supplements here.

How does saw palmetto work (mechanism of action)?

Saw palmetto is a plant called Serenoa repens. Some people also refer to saw palmetto as American dwarf palm tree or cabbage palm.

The berries from saw palmetto contain chemicals that are thought to have anti-inflammatory effects. These chemicals may also change the way that sex hormones, such as estrogen and testosterone, work in the body. But saw palmetto does not seem to help reduce symptoms in people who have an enlarged prostate. It is not clear how saw palmetto might work to reduce hair loss.

Herbal products, like saw palmetto, naturally contain many different chemicals. The amounts of each chemical in a specific saw palmetto product may vary from product to product. Some, none, or all of these chemicals may have effects on the body. These effects may change depending on how much of each chemical is found in the product you are taking.

How should I store saw palmetto?

You should store saw palmetto according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of saw palmetto?

The most common side effects of saw palmetto are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Diarrhea
• Dizziness
• Headache
• Decreased sex drive
• Runny nose
• Tiredness

There may be other side effects of saw palmetto that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of saw palmetto?

While less common, the most serious side effects of saw palmetto are described below, along with what to do if they happen.

Severe Allergic Reactions. Saw palmetto may cause allergic reactions, which can be serious. Stop taking saw palmetto and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Precautions

Who should not use saw palmetto?

Allergies to Ingredients. People who are allergic to any of the following should not take saw palmetto.

• American dwarf palm tree
• Cabbage palm
• Saw palmetto
• Serenoa repens
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific saw palmetto products they stock.

What should I know about saw palmetto before using it?

Saw palmetto is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep saw palmetto out of the reach of children.

Herbal products, such as saw palmetto, naturally contain many different chemicals. The amount of each chemical in a specific saw palmetto product can change for many reasons, including the area where the plant was grown, the weather during growth, the time of year when it was harvested, and the way that the plant was processed after it was harvested. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

If you have symptoms of an enlarged prostate, such as having a hard time peeing, a weak stream, or dribbling when you pee, call your health care provider. Saw palmetto may not be an appropriate option for treating prostate problems or other urinary problems.

The FDA has not tested saw palmetto products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

What should I tell my health care provider before using saw palmetto?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if saw palmetto is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions.Tell your health care provider if you have any of the following.

• Kidney or liver problems
• Upcoming surgery or medical procedure

Other Medicines and Supplements.Saw palmetto may interact with other medicines and supplements. Before taking saw palmetto, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. Saw palmetto may cause harm to an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if saw palmetto passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does saw palmetto interact with foods or drinks?

There are no known interactions between saw palmetto and foods or drinks.

It is unknown if drinking alcohol will affect saw palmetto, but drinking alcohol while taking saw palmetto could increase your risk for dizziness.

Does saw palmetto interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

The interactions between saw palmetto and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with saw palmetto is incomplete. Always check with your health care provider before using saw palmetto with any medicines.

Dosing

What should I do if I accidentally use too much saw palmetto?

If you or someone else has used too much saw palmetto, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Dietary supplements that contain saw palmetto are usually made from the berries of the plant. Read the product label closely and speak with a health care provider about how to use saw palmetto safely. Do not take double or extra doses, even if you miss a dose.