Saw Palmetto Side Effects in Men
Natural supplements for prostate health often include an ingredient called saw palmetto. Saw palmetto contains compounds that prevent testosterone from becoming DHT, a hormone related to enlarged prostate and male pattern baldness. Consequently, saw palmetto should improve many symptoms of enlarged prostate and may even encourage hair growth.
Of course, any potent natural ingredient comes with a risk of negative side effects. What side effects does saw palmetto cause? And do they outweigh its positive effects? Let’s examine saw palmetto side effects in men, both the good and the not-so-good, to determine its efficacy.
Saw Palmetto: The Positive Side Effects for Men
One quality in favor of saw palmetto as a male supplement ingredient is its multiple established uses. Saw palmetto is most commonly used by men with benign prostatic hyperplasia (BPH), which is the medical term for a noncancerous enlarged prostate. However, saw palmetto benefits several other common male health issues, including erection issues and baldness.
1. Shrinks Prostate Lining
During puberty, DHT exposure encourages cells in the prostate gland to grow and multiply rapidly. While this is necessary to mature the prostate in young men, as men age DHT keeps stimulating prostate cell growth unnecessarily. Consequently, doctors believe DHT is a major contributor to enlarged prostate.
For instance, one study measured changes in men’s prostate tissues after 6 months taking 320 mg saw palmetto per day. Saw palmetto reduced swelling in prostate epithelium, the inner lining of the prostate gland which surrounds the urethra.
Interestingly, researchers concluded these effects occurred without altering testosterone or DHT levels. Nevertheless, scientists believe shrinking prostate lining is a reliable positive side effect of saw palmetto.
2. Improves Urination
When saw palmetto shrinks prostate lining, the most pronounced effects are an improvement in urinary flow speed and a reduced need to urinate frequently at night. These are also two of the most common symptoms of BPH, and they often decrease quality of life greatly.
Saw palmetto trials produce mixed results on urinary flow. In one study, a 320 mg daily dose saw palmetto reduced need for middle-of-the-night bathroom trips by 45% and increased urine flow rate by 50%. But, another study using an identical dosage showed no difference between saw palmetto and placebo.
Despite these mixed results, many scientists promote saw palmetto as the most effective natural treatment for urinary symptoms related to enlarged prostate. Some studies even conclude saw palmetto improves these symptoms nearly as well as the prescription medication Finasteride.
3. Decrease Erection Problems Associated with Enlarged Prostate
Unfortunately, enlarged prostate also contributes somewhat to erectile dysfunction. Luckily, saw palmetto also improves erectile function. This gives saw palmetto an advantage over many enlarged prostate medications, which can worsen erectile dysfunction.
In a 2012 study, 82 men took 320 mg saw palmetto daily for 8 weeks. At the end of the study, sexual function scores improved by almost 10 points on a standardized assessment scale.
However, not all men experience improved erections after taking saw palmetto. Still, these results are encouraging for men whose enlarged prostate affects their sexual performance.
4. Reduce Male Pattern Baldness
Lastly, saw palmetto offers hope to men suffering from male pattern baldness, particularly young men who don’t want the sexual side effects of prescription treatments.
Two trials show saw palmetto produces results for a significant percentage of men. After 2 years of 320 mg saw palmetto, 38% of men in one study had increased hair growth. In another study, 60% of men responded to treatment with improved hair growth.
These results indicate saw palmetto isn’t a magic bullet against male pattern baldness. But, saw palmetto may be a good first option to utilize before trying more drastic methods to decrease baldness.
Potential Negative Side Effects of Saw Palmetto
Knowing saw palmetto produces numerous benefits, you may be surprised to learn it’s associated with very few side effects.
The most common saw palmetto side effects are gastrointestinal issues. These include upset stomach, vomiting, constipation, or diarrhea. However, in many saw palmetto studies, side effects occurred just as commonly in those taking the placebo as those taking saw palmetto.
Because saw palmetto likely acts as a 5-alpha-aromatase inhibitor, men sometimes experience side effects related to alterations in sex hormone levels. Shifts in testosterone and DHT can result in lowered libido, testicular discomfort, and greater difficulty producing an erection. Similarly, saw palmetto is known to have some anti-estrogen effects.
Other side effects attributed to saw palmetto include headache and dizziness.
Saw palmetto possibly increases risk of bleeding, especially in those with bleeding disorders or who are on anti-coagulant medications. For this reason, experts recommend being cautious about taking saw palmetto before surgery or dental work.
Saw Palmetto’s Side Effects: The Bottom Line for Men
Because years of research haven’t revealed any major side effects caused by saw palmetto, this plant extract seems like a good option for men who want to reduce symptoms of enlarged prostate or male pattern baldness.
To make sure you get the most effective saw palmetto extracts, look for fat-soluble saw palmetto extracts because they absorb best. And, be sure to verify any saw palmetto extract contains beta sitosterol, the saw palmetto extract component which promotes prostate health.
-  “Saw Palmetto – Topic Overview.” WebMD. 2009 Jun 30.
-  “Benign prostatic hyperplasia.” University of Maryland Medical Center. 2011.
-  “Saw palmetto.” University of Maryland Medical Center, 2011.
-  WebMD. “Saw Palmetto.”
-  Overmyer, M. “Saw palmetto shown to shrink prostatic epithelium.” Urology Times. 27.6 (1999): 42.
-  Champault, G, J C Patel, and A M Bonnard. “A double-blind trial of an extract of the plant Serenoa repens in benight prostatic hyperplasia.” British Journal of Clinical Phamacology. 18.3 (1984): 461-462.
-  Bent, S, C Kane, et al. “Saw palmetto for benign prostatic hyperplasia.” New England Journal of Medicine. 354.6 (2006): 557-66.
-  “Phytotheraphy for benign prostatic hyperplasia.” Public Health Nutrition. 3.4A (2000): 459-72.
-  “Physical Causes of Erectile Dysfunction.” WebMD. 2013.
-  Suter, Andreas, Reinhard Saller, Eugen Riedi, and Michael Heinrich. “Improving BPH symptoms and sexual dysfunctions with a saw palmetto preparation? Results from a pilot trial.” Phytotherapy Research. 27.2 (2013): 218-226.
-  Rossi A, E Mari, et al. “Comparative effectiveness of finasteride vs Serenoa repens in male androgenetic alopecia: a two-year study.” International Journal of Immunopathology and Pharmacology. 25.4 (2012): 1167-73.
-  Praeger, N, K Bickett, N French, and G Marcovici. “A randomized, double-blind, placebo-controlled trial to determine the effectiveness of botanically derived inhibitors of 5-alpha-reductase in the treatment of androgenetic alopecia.” Journal of Alternative and Complementary Medicine. 8.2 (2002): 143-52.
-  Di Silverio, F, G D’Eramo, et al. “Evidence that Serenoa repens extract displays an antiestrogenic activity in prostatic tissue of benign prostatic hypertrophy patients.” European Urology. 21.4 (1992): 309-14.
-  Drassinower, Sighi, and Frank Fabian. “The Key to Healthy Prostate and Andropause: Information and Action.” Key Biscayne: Nature’s Life & Health Inc., 2005. 78-79.