Human growth hormone is the so-called fountain of youth, and many celebrities are fans.
Actress Suzanne Somers calls it "sex in a capsule." Actor Nick Nolte calls it "a systems repair" for the body, and actor Sylvester Stallone used it to get buff for his role in the movie "Rambo IV." Some sports superstars have even gotten themselves into legal trouble for allegedly using it to enhance their performance.
But human growth hormone, or hGH, is not just for celebrities anymore. Ordinary Americans are turning to the product that many proponents claim turns back the clock on aging, builds muscle mass and strengthens bones. The hormone is illegal if used for anti-aging and can only be prescribed by a doctor if a patient's blood test shows hormone levels that are too low.
Former NFL player Ed Lothamer and his wife, Beth, started injecting hGH about eight years ago after their doctor legally prescribed it. They said that when they hit middle age, they just weren't feeling like themselves anymore.
"I think the older you get, the more depressed you get and the golden years are really the rusty years," Beth Lothame, 64, told "Good Morning America."
Within months of starting the injections, they noticed a big change, including better skin and a spiced-up sex life.
HGH occurs naturally in the body. It promotes growth in children and diminishes with age. But people such as like Beth Lothamer have been injecting it back into their bodies.
Her regimen includes exercise, eating healthy and taking hGH and other medications, including melatonin and progesterone. For her husband, 69, it's testosterone. The hGH itself costs $150 per bottle and the Kansans spend between $8,000 and $10,000 a year on all of the treatments, including doctor visits and medications.
Ed Lothamer says he feels 20 years younger. And his wife said she feels as though she's in her 40s.
She says she sleeps much better and runs three miles a day. "I'm up all day long, I don't ever sit down," she said.
Her husband said, "When I come home and I have things to do, I still have plenty of drive left and I do those things."
A study in the New England Journal of Medicine even backs up some of their claims, finding that men who took hGH for six months reduced their body fat by more than 14 percent and increased muscle mass by 8.8 percent.
Results like those only come, however, when hGH is injected as prescribed, not when applied through the creams and lotions also advertised as hGH and available on the market.
But the practice of injecting hGH is highly controversial and potentially risky.
"Growth hormone has a number of dangerous side effects, primarily diabetes," Dr. Thomas Perls of Boston Medical Center told "GMA." "It increases blood sugar and can cause diabetes. It can also cause a swelling of the joints, enlargement of organs, hypertension, sometimes breathing problems."
HGH has even caused cancer in mice.
"The anti-aging industry tells people that these hormones will make you young again, that they'll reverse years of aging. And this is a total ruse," Perls added. "Part of it is that people equate hormones with youth, and so they think, by getting these drugs, they're going to be young again."