Saw Palmetto

Overview Information

Saw palmetto is a tree. Its ripe fruit is used to make medicine.

Saw palmetto is, most commonly used for decreasing symptoms of an enlarged prostate called benign prostatic hypertrophy (BPH), but some scientific evidence shows that it does not work. Saw palmetto is also used to prevent complications from prostate surgery and for treating certain types of prostate conditions.

How does it work?

Saw palmetto doesn’t shrink the overall size of the prostate, but it seems to shrink the inner lining that puts pressure on the tubes that carry urine. Saw palmetto also might prevent testosterone from being converted to a more potent form of testosterone called dihydrotestosterone (DHT). It is thought that some types of hair loss are caused by an increased sensitivity of hair follicles to DHT. Reduced levels of DHT may help prevent these types of hair loss.

Uses & Effectiveness?

Possibly Effective for

Prostate surgery (transurethral resection of the prostate; TURP). Research shows that taking 320 mg of saw palmetto daily for 2 months before prostate surgery can reduce the time spent in surgery, blood loss, the development of problems during surgery, and the total time spent in the hospital. However, one small study found that taking 160 mg of saw palmetto per day for 5 weeks before surgery does not lower the risk of problems during surgery.

Side Effects & Safety

Saw palmetto is LIKELY SAFE for most people when taken by mouth for up to three years. Side effects are usually mild. Some people have reported dizziness, headache, nausea, vomiting, constipation, and diarrhea. Some people have reported that saw palmetto causes impotence. However, these side effects do not seem to occur any more often with saw palmetto than with a sugar pill.

There is some concern that saw palmetto might cause liver or pancreas problems in some people. There have been two reports of liver damage and one report of pancreas damage in people who took saw palmetto. However, there is not enough information to know if saw palmetto was the actual cause of these side effects.

Saw palmetto is POSSIBLY SAFE when administered into the rectum appropriately for up to 30 days. It is not known if it is safe to use for longer periods of time.

Special Precautions & Warnings:

  • Pregnancy and breastfeeding: Saw palmetto is LIKELY UNSAFE when taken by mouth during pregnancy or breastfeeding. It acts like a hormone, and this could be dangerous to the pregnancy. Don’t use during pregnancy or breastfeeding.
  • Surgery: Saw palmetto might slow blood clotting. There is some concern that it might cause extra bleeding during and after surgery. Stop using saw palmetto at least 2 weeks before a scheduled surgery.


The following doses have been studied in scientific research:



  • Prostate surgery (transurethral resection of the prostate, TURP): 320 mg of saw palmetto extract daily for 2 months before surgery.


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