Saw palmetto (Serenoa repens) has been widely used as a natural remedy for benign prostatic hyperplasia (BPH) symptoms. However, the evidence supporting its efficacy is mixed and has evolved over time.
Proposed Mechanisms of Action
Saw palmetto is believed to work through several potential mechanisms:
- Hormonal effects: It may affect testosterone levels in the body and reduce the activity of 5-alpha-reductase, an enzyme that promotes prostate cell growth4.
- Anti-inflammatory properties: The herb appears to have an anti-inflammatory effect on the prostate, which may be enhanced when combined with other compounds like lycopene and selenium4.
- Inhibition of tumor cell growth: Animal studies suggest that saw palmetto might inhibit the growth of tumor cells, indicating potential benefits for prostate cancer treatment4.
Evaluation of Research Findings
Early Studies and Initial Promise
Initial small-scale studies in the 1980s and 1990s suggested that saw palmetto could be beneficial for various prostate issues, including BPH2. These early findings contributed to the widespread belief in its effectiveness.
Recent Large-Scale Studies
However, more recent and rigorous research has challenged the efficacy of saw palmetto:
- NIH-funded studies: Large-scale studies funded by the National Institutes of Health (NIH) in the past two decades found that saw palmetto was no more effective than placebo in treating BPH symptoms2.
- Cochrane review: A 2012 Cochrane review of 32 randomized controlled trials involving 5,666 men concluded that Serenoa repens, even at two to three times the usual dose, did not improve urinary flow measures or prostate size in men with lower urinary tract symptoms consistent with BPH3.
- High-dose trial: A 2011 double-blind, placebo-controlled, randomized trial with 369 older men showed that saw palmetto extract, even at three times the standard daily dose (320 mg), did not reduce urinary symptoms associated with BPH more than placebo3.
Combination Therapy
Some research suggests that saw palmetto may be more effective when combined with other compounds:
- A 2014 randomized trial of 225 men found that a combination therapy of saw palmetto, lycopene, selenium, and tamsulosin was more effective than single therapies in improving International Prostate Symptom Score and increasing maximum urinary flow rate3.
- The SPRITE study, a 2018 phase IV clinical trial with 404 participants, found that treatment with saw palmetto, selenium, and lycopene was not inferior to tadalafil 5 mg for improving urinary symptoms and flow rate in men with lower urinary tract symptoms3.
Safety Profile
Saw palmetto appears to be well-tolerated by most users, with only mild side effects such as stomach discomfort reported3. It does not seem to affect prostate-specific antigen (PSA) levels or interact with medications3.
Conclusion
While saw palmetto has a long history of use and some studies suggest potential benefits, particularly in combination with other compounds, the current body of evidence does not strongly support its efficacy for managing BPH symptoms. Large-scale, high-quality studies have consistently found that saw palmetto alone is not significantly more effective than placebo for treating urinary symptoms related to BPH123.Given the mixed evidence, individuals considering saw palmetto for BPH should consult with their healthcare provider to discuss the most appropriate treatment options based on their specific symptoms and medical history.
