Does Saw Palmetto Lower Blood Pressure?

The herbal supplement saw palmetto is used by some in an attempt to help with an enlarged prostate gland, a lower sex drive, hair loss or other health issues, though the evidence is lacking. But what about high blood pressure — can it help with that?

Hypertension, the medical term for high blood pressure, is a health condition that requires regular management with the help of a doctor. This common condition puts you at a higher risk for stroke, heart attack and many other complications, according to the American Heart Association, making it all the more important to follow a treatment plan recommended by your doctor.

Usually, treatment involves medication. But some people may look to natural or alternative therapies in addition to prescriptions to help control their blood pressure. That's how saw palmetto — which is actually a palm tree grown in the southeastern part of the United States — may get on your radar.

Saw palmetto is not known to help lower blood pressure, says Jordana B. Cohen, MD, an assistant professor of medicine at the Hospital of the University of Pennsylvania in Philadelphia. She says she's not aware of any research that supports the use of saw palmetto to help reduce high blood pressure.

Plus, a January 2011 study in ​Prostate​ found that certain retail forms of saw palmetto extract contain tyramine, which can interact with other medications, particularly a certain class of antidepressants called monoamine oxidase inhibitors (MAOIs), and cause a severe increase in blood pressure.

The National Center for Complementary and Integrative Health (NCCIH) outlines several complementary health approaches for high blood pressure, but does not include saw palmetto on the list. Rather, it suggests relaxation techniques, yoga, garlic and omega-3 fatty acids as possibly safe and effective ways to support healthy blood pressure.

Although saw palmetto is not shown to be effective in lowering blood pressure, it is sometimes used by people to address other health conditions, such as an enlarged prostate (called benign prostatic hyperplasia). But there are no studies showing that saw palmetto is particularly effective for any health problem, according to the NCCIH.

Saw palmetto is generally well-tolerated. However, those using it must keep in mind certain potential side effects, Dr. Cohen says. These include:

• Dizziness
• Nausea
• Headaches
• Stomach upset

Saw palmetto also may have some rare side effects such as pancreatitis (inflammation of the pancreas), cholestatic hepatitis (a condition where the flow of bile from the liver is blocked or reduced) and intraoperative bleeding, Dr. Cohen says.

​Read more:​ 103 High Blood Pressure Statistics You Should Know

Saw palmetto is a supplement, so it is not regulated by the U.S. Food and Drug Administration as rigorously as a prescription med. "There is the possibility for other active substances to be present that are not reported that may be dangerous or toxic," Dr. Cohen says. The amount of saw palmetto in a supplement also may vary, based on the brand, making it hard to determine how much you're actually getting. Because any benefits have yet to be firmly proven, there is no set saw palmetto dosing recommendation, either.

Saw palmetto can potentially interact with other medications, including oral birth control, hormone therapy, anti-platelet drugs, anticoagulants and monoamine oxidase inhibitors, Dr. Cohen says. This means that those drugs could stop working effectively or cause other issues if you start taking saw palmetto. Always talk to your doctor before using saw palmetto or any other dietary supplement.

Saw palmetto may cause severe bleeding, so doctors advise that people on blood thinners or who are at risk for bleeding not use it. It's also recommended to stop taking saw palmetto at least two weeks before any surgery, Dr. Cohen says.