Can a natural remedy cause long-term harm? Saw palmetto, a herbal supplement derived from the berries of the Serenoa repens plant, is widely used to manage urinary symptoms and support prostate health, especially in men with benign prostatic hyperplasia (BPH).

It’s found in many dietary supplements and is often viewed as a safer alternative to prescription drugs. However, its growing popularity doesn’t erase the concerns about its long-term use. Some case reports have raised concerns about liver damage and hormonal effects in people using saw palmetto, though clear causal links are unconfirmed.

This guide breaks down the potential risks, current safety data, and what long-term users need to know.

Saw palmetto is often used as a supplement by people managing urinary symptoms, including those associated with benign prostatic hyperplasia (BPH). It is also considered in cases of chronic prostatitis and symptomatic benign prostatic hyperplasia, where traditional treatments may not be preferred.

Saw palmetto is a dietary supplement made from the berries of the Serenoa repens, a palm native to the southeastern United States. These berries are used in supplement formulations commonly marketed for prostate health support.

Many men turn to a saw palmetto herbal blend as a form of herbal medicine to help relieve issues like frequent urination, reduced stream, and nighttime urgency—common symptoms of benign prostatic hypertrophy. The increased use of palmetto supplements in dietary supplements reflects broader interest in natural approaches to the treatment of benign prostatic conditions.

Research into the pharmacology and therapeutic efficacy of saw palmetto has shown that Serenoa repens extract may display anti-inflammatory activity and act as a mild 5-alpha-reductase inhibitor, which could impact levels of DHT (dihydrotestosterone). These effects are being studied for their potential impact on lower urinary tract symptoms, though results are mixed.

Several studies, including randomized controlled trials, double blind placebo controlled trials, and systematic reviews, have assessed the therapeutic efficacy of palmetto extracts. While some findings show promise in addressing symptomatic benign prostatic hyperplasia, others, such as the trial of saw palmetto led by Kane C. Shinohara, highlight the inconsistency in outcomes compared to placebo-controlled trials. Because of these mixed results, many experts continue to call for more robust data from randomized international studies and controlled trials of saw palmetto.

Though often considered safe, long-term use of saw palmetto may carry risks that aren't fully understood. Studies have focused mostly on short-term results, leaving questions about chronic use.

Mild side effects are the most frequently reported with saw palmetto use. These reactions are typically short-term and manageable, especially when the supplement is taken at standard doses. Still, some individuals may be more sensitive to herbal medications like palmetto extract.

Here are the most commonly reported side effects:

• Stomach discomfort or nausea

• Headaches

• Dizziness or lightheadedness

• Mild fatigue

• Digestive changes, such as bloating or gas

While most people tolerate saw palmetto well, it’s important to monitor your response and speak with a healthcare provider if symptoms persist.

Long-term use of saw palmetto has not been studied as extensively as its short-term effects. While many people use it without issue, case reports and reviews suggest several potential risks that may emerge with prolonged use, especially in individuals with underlying conditions or those taking other medications.

Here are some of the possible long-term risks:

• Palmetto-induced pancreatitis, a rare but serious inflammation of the pancreas

• Gastrointestinal distress, including abdominal pain or long-term digestive discomfort

• Drug-induced liver injury, especially when combined with other supplements or medications

• Increased bleeding risk, particularly for people on blood thinners

• Hormonal imbalances, due to the supplement’s effect on testosterone and DHT levels

More randomized controlled trials are needed to confirm how these risks impact different groups, including benign prostatic hypertrophy patients who take saw palmetto daily.

Saw palmetto is believed to affect levels of dihydrotestosterone (DHT), a hormone involved in prostate growth, although findings are mixed. While this effect may offer benefits for people with benign prostatic hyperplasia or chronic prostatitis, altering hormone levels can lead to unwanted side effects over time.

Here are some potential hormonal impacts of long-term saw palmetto use:

• Reduced libido, especially in men

• Mood changes, such as irritability or low mood

• Lower energy levels, possibly tied to hormone shifts

• Interference with hormone replacement therapy, making treatments less effective

• Changes in testosterone-DHT balance, which may affect prostatic tissue over time

Because of these concerns, healthcare providers often advise caution with prolonged use of saw palmetto, especially in people managing hormone-sensitive conditions.

Not everyone reacts to herbal supplements the same way. While some men report health benefits from the use of saw palmetto, others may face adverse events with extended use, especially those with pre-existing conditions or who are taking other herbal medicines.

To reduce the risk of adverse events, follow dosage guidelines supported by randomized controlled trials and systematic reviews. Most studies examining the therapeutic efficacy of saw palmetto use a standard dose of 160 mg of lipidosterolic extract twice daily. However, dietary supplements vary and may include forms like saw palmetto extract, palmetto oil, or a saw palmetto herbal blend.

It’s important to speak with a healthcare provider before using saw palmetto long-term, especially if you're managing chronic pelvic pain, taking other herbal medications, or using treatments for benign prostate hyperplasia. Combining palmetto extracts with prescription medications can increase the likelihood of drug-induced liver injury or other complications.

Certain individuals should avoid saw palmetto. This herb may affect hormonal pathways, so people taking hormone therapies or certain medications, like blood thinners, should talk to their doctor before using it.

Those with liver conditions are also at higher risk for liver-related complications or bleeding issues. Men with prostate cancer should consult a healthcare provider first, as the effects of saw palmetto on prostate cancer risk or progression are not fully understood and have not been confirmed in clinical studies.

As men age, prostate changes can affect comfort, urinary habits, and overall quality of life. Alerna’s Prostate Support supplement is formulated to help address these concerns with a blend of herbs traditionally used to support prostate health and urinary flow. It offers a steady, natural approach to long-term wellness.

Some prostate supplements focus only on saw palmetto. While popular, saw palmetto alone may not provide comprehensive support, and it may carry risks for people taking certain medications. Alerna’s formula avoids overreliance on a single ingredient by combining multiple well-studied botanicals.

We’ve included nettle root and pumpkin seed extract, along with saw palmetto, to target different aspects of prostate and urinary health. These ingredients are also rich in antioxidants, which may help reduce oxidative stress in the prostate over time. The result is a daily-use formula built for balance, not shortcuts.

Relying on saw palmetto alone may not be enough for everyone. While it’s often used to relieve urinary symptoms related to benign prostatic hyperplasia, clinical results are mixed, and some men may experience side effects like hormonal shifts, liver strain, or increased bleeding risk, particularly when combined with other medications.

It’s important to treat saw palmetto as just one part of a broader approach to prostate health. For those looking for a supplement that reflects this, multi-ingredient formulas like Alerna’s may offer more complete support without the potential downsides of a single-compound product.

Click here to learn more about Alerna's Prostate Support Supplements to enhance your prostate health and overall well-being.

Saw palmetto remains a widely used herbal supplement for managing urinary symptoms related to benign prostatic hyperplasia. While many people tolerate it well in the short term, long-term use raises valid concerns, particularly around hormonal changes, liver function, and drug interactions.

Because the clinical data on extended use is still limited, it’s important to evaluate the risks and benefits carefully. For those seeking ongoing prostate support, looking into supplements that combine multiple well-researched ingredients rather than relying on saw palmetto alone may offer a safer and more balanced approach.

Always speak with a healthcare provider before starting or continuing any prostate health supplement, especially if you have pre-existing conditions or take medications that could interact with herbal products.

The information provided in this article is for educational and informational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Please consult with your healthcare provider before starting any new dietary supplement, especially if you are pregnant, nursing, have a medical condition, or are taking other medications. Never disregard professional medical advice or delay in seeking it because of something you have read in this article.

1. Bent, S., Kane, C., Shinohara, K., Neuhaus, J., Hudes, E. S., Goldberg, H., & Avins, A. L. (2006). Saw palmetto for benign prostatic hyperplasia. The New England journal of medicine, 354(6), 557–566. https://doi.org/10.1056/NEJMoa053085

2. Foley, C. L., & Kirby, R. S. (2003). 5 alpha-reductase inhibitors: what's new?. Current opinion in urology, 13(1), 31–37. https://doi.org/10.1097/00042307-200301000-00006

3. Ng, M., Leslie, S. W., & Baradhi, K. M. (2024). Benign Prostatic Hyperplasia. In StatPearls. StatPearls Publishing.

4. Suzuki, M., Ito, Y., Fujino, T., Abe, M., Umegaki, K., Onoue, S., Noguchi, H., & Yamada, S. (2009). Pharmacological effects of saw palmetto extract in the lower urinary tract. Acta pharmacologica Sinica, 30(3), 227–281. https://doi.org/10.1038/aps.2009.1