Numerous plants contain cholesterol-like compounds called sitosterols and their close relatives sitosterolins. A special mixture of these called beta-sitosterol is used for the treatment of benign prostatic hyperplasia (BPH) .

What Is Beta-Sitosterol Used for Today?

Some conditions are luckier than others. For some mysterious reason, there seem to be more useful herbal treatments for BPH than almost any other disease. Beta-sitosterol joins saw palmetto , pygeum , nettle , and grass pollen as a moderately well-documented treatment for BPH.

Based on highly preliminary evidence, it has been suggested that sitosterols may also help strengthen the immune system . 2 In particular, one study suggests that beta-sitosterol can help prevent the temporary immune weakness that typically occurs during recovery from endurance exercise , and can lead to a post-race infection. 3

What Is the Scientific Evidence for Beta-Sitosterol?

A review of the literature, published in 1999, found a total of four double-blind placebo-controlled studies on beta-sitosterol for BPH, enrolling a total of 519 men. 4-7 All but one of these studies found significant benefits in both perceived symptoms and objective measurements, such as urine flow rate.

The largest study followed 200 men with BPH for a period of 6 months. 8 After the trial was completed, many of the participants were followed for an additional year, during which the benefits continued. 9 Similar results were seen in a 6-month, double-blind trial of 177 individuals. 10

Beta-sitosterol binds to prostate tissue and affects the metabolism of prostaglandins, substances found in the body that affect pain and inflammation. 1 However, it is not clear whether this is the correct explanation for how beta-sitosterol might help in BPH.

Dosage

The daily dosage of beta-sitosterol is 60 to 135 mg. Effects usually take 4 weeks to develop.

Safety Issues

Although detailed safety studies have not been performed, beta-sitosterol is believed to be safe. No significant side effects or drug interactions have been reported. 11