"You are paying a lot of money for a therapy that may have minimal or no benefit and yet has a potential for some serious side effects," Dr. Hau Liu of Stanford said, according to the Chicago Tribune.
"The appropriate conclusion is that it is premature to be using human growth hormone for this purpose," said S. Jay Olshansky, a professor at the University of Illinois at Chicago who had no part in the study. "It is also illegal."
The use of HGH, which has been widely reported as an anti-aging therapy on the Internet, is approved for use in adults for only two conditions: the wasting syndrome caused by AIDS and growth hormone deficiency. It is also used to treat growth problems in children.
The researchers compiled results from 31 studies that involved controlled trials of HGH in healthy adults. They found that use of the treatment for six months resulted in an increase of less than 5 pounds of muscle mass and a decrease of about the same amount in fat.
However, Dr. Liu said the benefits are not very substantial, especially considering the side effects.
"If you went to a gym pretty regularly, you might get that change without breaking into too much of a sweat, and you wouldn't spend $1,000 to $2,000 per month," Liu said.
They found that HGH did not have an effect on bone density, cholesterol and lipid levels and maximal oxygen consumption. However, they did find it could cause an array of negative side effects, most commonly edema, or soft-tissue swelling, which occurred in about half of those who received the drug. Nineteen percent were affected by carpal tunnel syndrome and 21 percent by joint and bone pain and swelling. The breast area of about 6 percent of men who took HGH became enlarged, which is clinically known as gynecomastia.
"Everyone is looking for the fountain of youth, but you've got to really think about what this drug is doing to you," Liu said.
The results of the study are published in the Annals of Internal Medicine.
