Saw palmetto (Serenoa repens) is a small palm tree native to the southeastern United States. Its ripe berries are the source of the extract used in popular dietary supplements, making it one of the most frequently consumed supplements in men’s health. The supplement is primarily taken to address urinary symptoms commonly associated with an enlarged prostate. Understanding the scientific evidence regarding any potential effects on the cardiovascular system, particularly blood pressure, is important for consumers. This article examines the current research to determine saw palmetto’s influence on blood pressure and how it might interact with other medications.
Primary Uses and Mechanism of Action
The main reason men turn to saw palmetto is for the management of lower urinary tract symptoms linked to Benign Prostatic Hyperplasia (BPH). BPH is a non-cancerous enlargement of the prostate gland that can cause bothersome symptoms like frequent urination and difficulty emptying the bladder. Historically, the berries were also used in traditional medicine for a variety of conditions, including male pattern baldness.
The presumed mechanism of action for saw palmetto involves its ability to interfere with the body’s hormonal pathways. The extract contains certain fatty acids and phytosterols that are believed to inhibit the enzyme 5-alpha reductase. This enzyme is responsible for converting testosterone into the more potent androgen, dihydrotestosterone (DHT), which plays a significant role in prostate growth.
By potentially reducing DHT levels within the prostate tissue, saw palmetto may help to prevent the overgrowth of prostate cells. The supplement also exhibits anti-inflammatory properties, which is another proposed way it helps to alleviate urinary symptoms, as inflammation is often implicated in the development and progression of BPH.
Direct Evidence on Blood Pressure Effects
Clinical studies designed to assess the efficacy of saw palmetto for BPH have concurrently monitored vital signs, including blood pressure, to determine safety. The consensus from this body of research suggests that saw palmetto, when taken in isolation, does not cause any clinically significant changes to blood pressure readings. Large-scale trials, such as those funded by the National Institutes of Health, have specifically tracked changes in systolic and diastolic blood pressure over extended periods.
In one detailed safety assessment, researchers found that both the group taking saw palmetto extract and the placebo group experienced small, comparable declines in blood pressure and heart rate over the study period. There were no statistically significant differences in these measurements between the active treatment and placebo groups. This evidence supports the conclusion that the supplement is generally neutral with respect to blood pressure regulation.
Another study investigated the herb’s potential to affect blood pressure due to its in vitro activity as an alpha1-adrenoceptor antagonist, a mechanism that could theoretically lower blood pressure. Although minor reductions in supine blood pressure were noted, the study concluded that therapeutically used doses do not cause alpha1-adrenoceptor antagonism. Therefore, the current scientific literature does not support the use of saw palmetto as a treatment for high blood pressure, nor does it indicate that the supplement raises blood pressure.
Safety Profile and Medication Interactions
Saw palmetto is generally well-tolerated by most individuals, with reported side effects being infrequent and mild. The most common adverse effects include minor digestive issues, such as nausea or diarrhea, along with occasional reports of headache or dizziness. These symptoms are usually temporary and reversible upon discontinuation of the supplement.
A more serious concern involves the potential for drug interactions, particularly with medications that affect the cardiovascular system. Saw palmetto may possess antiplatelet properties, which means it could slow blood clotting. This effect can increase the risk of bruising or bleeding when the supplement is taken alongside anticoagulant or antiplatelet drugs, such as warfarin or aspirin.
Although the direct effect of saw palmetto on blood pressure is minimal, its interaction risk with prescribed antihypertensive drugs must be considered. While most clinical trials have found no serious adverse events with saw palmetto, the simultaneous use of any supplement with blood pressure medication should be discussed with a healthcare provider. Combining a supplement with a prescription drug always carries a risk of altering the drug’s effectiveness or increasing side effects.