New evidence shows that optimistic claims that repeated doses of human growth hormone can erase some of the ravages of age were too good to be true.

“Based on our study, we can’t recommend use of growth hormone,” said Dr. Maxine Papadakis. “This is not the Fountain of Youth.”

Papadakis, a doctor at the University of California Medical Center and the Veterans Administration Medical Center, both in San Francisco, said a six-month study of 52 healthy men 70 and older showed no improvement in physical performance or mental ability as a result of growth hormone injections.

She and six colleagues reported Monday in the Annals of Internal Medicine that the men gained about 4 percent in lean body mass and lost about 13 percent of their fat. But the changes came at a cost: Most suffered water retention, aching joints and stiff hands.

The term “lean body mass” refers to everything but fat, including muscle, tissues and water. So a 4 percent gain in lean body mass could include fluid retention. And, Papadakis warned, “growth hormone is quite pricey, $12,000 a year - for no benefit in function.”