Study: Men lost weight on testosterone therapy

(CBS News) In a new study, German researchers took a group of overweight men and restored their normal testosterone levels. The group lost weight, lowered their blood pressure, and improved their cholesterol.

The study looked at 115 obese men aged between 38-83 years with low testosterone levels, the BBC reports. Subjects were injected with the hormone every 12 weeks to increase levels. The research was paid for by Bayer Pharma, a manufacturer of testosterone replacement therapy. The study found no increased risk of prostate cancer, a side effect found in other studies. The findings were announced at the European Congress on Obesity.

Testosterone replacement therapy prescriptions have doubled over the last six years, according to the International Journal of Clinical Practice.

As prescriptions skyrocket, Dr. Harry Fisch, a urologist at New York's Weill-Cornell Medical Center, reminds us that testosterone should never go below normal levels in a man's lifetime. Fisch said Wednesday on "CBS This Morning," "A lot of people think that testosterone levels as you get older go below normal levels. That's not true."

Fisch, author of "The Male Biological Clock," said he can tell in a second when someone comes into his office if they have low testosterone. How? He looks at the size of belly.

"The bigger the belly the lower the testosterone," Fisch said.

For more on the study and why Fisch doesn't tell his patients to lose weight and exercise, watch the video in the player above.