For decades, “medical lore” has asserted that saw palmetto reduces the symptoms associated with an enlarged prostate. Benign prostatic hyperplasia (BPH) is the name given to non-cancerous enlargement of the prostate gland. The prostate gland is normally about the size of a walnut, is located at the base of the bladder, and produces 80%-90% of the total volume of the seminal fluid released during ejaculation. The prostate surrounds the urethra, the tube through which urine passes from the bladder to outside the body.
An enlarged prostate causes symptoms that men find annoying. Those symptoms are incomplete emptying of the bladder during urination, hesitancy, or delay, in the initiation of urination, decreased force of the urine flow requiring the patient to strain to urinate, and the need to get up at night to urinate. Doctors are able to quantify these symptoms by having patients answer a 7-item questionnaire called the American Urological Association (AUA) Symptom Score. Patients rank the severity of symptoms from 0-5, “0” being no symptoms and “5” being symptoms all the time. The maximum score is 35. A score of 0-7 is considered mild BPH, 8-19 is Moderate BPH, and 20-35 is severe BPH.
Saw palmetto is a shrublike palm tree that has “thorn-shaped leaves.” It grows in the southeastern United States and can grow to 10 feet tall. The “fruit” borne by the tree is used to make compounds used for “medicinal” purposes. As I mentioned above, medical lore has recommended saw palmetto as a natural substance that reduces the symptoms caused by the enlarged prostate. Using plants and herbs to treat a human medical problem is called phytotherapy.
Medical researchers have long been skeptical of the efficacy of saw palmetto. Doctors at Camp Pendleton Naval Hospital in California evaluated 27 prior studies and tabulated the results to decide once-and-for-all if it worked. The studies involved 4656 men at least age 50 given an average of 320 mg of saw palmetto daily. In 19 studies, saw palmetto alone was compared to placebo. In the other 8 studies, saw palmetto was combined with other phytotherapy agents and compared to placebo. To quantitate the results, AUA Symptom Scores were used. If the participant’s score improved by 3 points or more, the treatment was considered successful.
Results were as the skeptics suspected. After 3 to 6 months, the symptom score improved only 0.9 and the quality of life (QOL) score did not improve significantly. After 12 to 17 months, no significant change in AUA score or QOL score were recorded. This included saw palmetto alone and when combined with other phytotherapy agents. Thus, the National Institute for Health and Care Excellence and the American Urological Association do not recommend saw palmetto nor include it in the treatment guidelines.
Any benefit one with BPH might experience from taking saw palmetto is a perfect example of the strength and credibility of the placebo effect and not a result of the actual reduction in prostate size.
Reference: Hammer NC, Thiede J. Saw Palmetto for the Treatment of Lower Urinary Tract Symptoms due to Benign Prostatic Hyperplasia. Am Fam Phys 2024 May;109(5):396.
