|Androstenedione Supplements Do Not Help Build
WESTPORT, Jun 03 (Reuters Health) - Androstenedione does not improve muscle strength and may raise risks for cancer and heart disease, according to the results of a small study.
"The government should carefully consider intervening and remove androstenedione and its derivatives from the market," Dr. Charles Yesalis III, of Pennsylvania State University, in University Park, writes in an editorial commenting on the study in the June 2nd issue of The Journal of the American Medical Association.
In the study, Dr. Douglas S. King and colleagues at Iowa State University in Ames measured testosterone and estrogen levels, muscle size and strength, and blood lipids in 20 normotestosterogenic young men placed on an 8-week resistance-training regimen that included workouts 3 days per week. Ten of the men received 300 mg/day of androstenedione during weeks 1, 2, 4, 5, 7, and 8, while the other 10 received placebo.
At the end of the study, muscle strength and type 2 muscle fiber cross sections increased in both groups to a similar extent, Dr. King's group reports. Serum testosterone levels did not change with androstenedione administration, but serum estradiol and estrone concentrations did increase. This suggests that a "significant proportion" of the supplement was converted into these estrogens, the researchers say, which could increase the risk for gynecomastia and pancreatic cancer in men, and breast cancer in women.
They also found that men who took androstenedione showed a "significant lowering" in blood levels of HDL cholesterol.
In his commentary, Dr. Yesalis writes that the Iowa findings should raise public concern about the supplement, and trigger more research into its long-term health consequences.
He points out that current regulations give the US Food and Drug Administration (FDA) very limited power over androstenedione and other dietary supplements. "The FDA can intervene after it has proven the product is unsafe," he says, but notes that "by that time harm may have already taken place."