HOW DOES SAW PALMETTO WORK: INHIBITING THE CONVERSION OF TESTOSTERONE TO DHT
As previously discussed, one of the causes of BPH is the influence of DHT on prostate cells. If the levels of DHT can be decreased within prostate tissue, there is a good chance the gland will shrink enough to allow urine to flow out easier. Can SP block the conversion of testosterone to DHT?
It depends on which laboratory is doing the study. In 1993, scientists at Merck Research Laboratory in Rahway, New Jersey, after evaluating Proscar and SP on rat prostate tissue, concluded that SP does not have the ability to block the conversion of testosterone to DHT while finasteride (Proscar) does. A year later, a research group from Hopital Universitaire Cochin, in Paris, determined that the administration of SP extract for a one-week period to 32 healthy male volunteers did not reduce DHT levels in blood; but Proscar administration at 5 mg a day did reduce blood DHT levels. Merck which sells Proscar, funded this study as well.
The findings by Merck researchers conflict with earlier studies financed by the company promoting Permixon which found that SP did have the ability to block the conversion of testosterone to DHT.
Many individuals now have easy access to Medline and other medical data information systems through their computer. For instance, if someone wanted to find out more about SP, they would type in saw palmetto or Serenoa repens and abstracts of studies on this herbal extract would show on the screen. What doesn't appear within the abstract, but is mentioned in the full article published in a journal, is who is funding the study. What's disturbing is that doctors, the media, or anyone who wants to learn more about SP, or any other supplement, won't realize that some of the information they are reading may not be completely accurate. The results of a particular study may be influenced by the source of the funding.
Dr. Franco Di Silverio and colleagues, from the University of La Sapienza in Rome, Italy, wanted to find out the effect of finasteride (Proscar) and SP on the concentrations of DHT in prostate tissue. Six patients were given SP extract (Permixon) at 320 mg/ day for 3 months, 9 patients were given finasteride, and 9 patients were not given any medicines. Prostate tissue was removed surgically from these patients at the conclusion of the three months and levels of DHT were evaluated. In the untreated group, DHT levels were 1121 mg/pg DNA (pg means picogram, one trillionth of a gram). Patients on finasteride showed a level of 232, while those on SP had levels of 256. This study indicates that both finasteride and SP extracts have the ability to decrease DHT levels in prostate tissue. More studies are needed to confirm these findings.
Interestingly, SP does not seem to influence levels of testosterone in the blood. When twenty men, aged 50 to 75 years, suffering from BPH were given 160 mg of SP extract twice a day for one month, there were no changes in their blood levels of testosterone, follicle-stimulating hormone, and luteinizing hormone.
To make things more conflicting, an additional study was published by researchers at the Endocrine Unit of Szent-Gyorgyi Albert Medical University, in Szeged, Hungary. An SP extract, called Strogen forte was found to inhibit prostatic 5-alpha-reductase in rats and humans.
I have read quite a number of articles on SP in the last few years in lay magazines. Almost every one of the authors reports that the mechanism of action of SP is due to its blocking the conversion of testosterone to DHT. Based on the review of all the studies published thus far, I cannot come to a definite determination on whether compounds within SP block the conversion of testosterone to DHT. It would be premature to make this claim. The results of independently funded studies are needed.
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Men's Health Erectile Dysfunction