Hollywood’s latest health craze is — wait for it — human growth hormone. Alana Stewart tells the new March issue of Vanity Fair: “I had started noticing a few gray hairs coming in. But I noticed that when I was taking it — no gray hairs.” Stewart, the leggy model and former wife of George Hamilton and Rod Stewart, was the sole H.G.H. user who agreed to be identified in the piece by Ned Zeman. The drug costs as much as $10,000 a year, and is described in celebrity circles as “a fountain of youth in a syringe.” “People talk about H.G.H. the way they talk about people who get Botox or Viagra,” says a movie producer. Another filmmaker reports he uses it to perk up his sex life. The results: “My internal organs got healthier quickly. And I could feel it . . . It very much imbues you with a sense of clarity and confidence.” Dr. Andre Berger, a Los Angeles-based H.G.H. expert, said, “People are going to be living longer. This is about preventing the chronic diseases and all the ravages that affect your quality of life.” While the Mayo Clinic lists side effects including carpal tunnel syndrome, swelling in the limbs and enlargement of male breast tissue, Dr. Uzzi Reiss tells Zeman, “I’ve been taking H.G.H. for many years. I have the energy and vibrancy of a man half my age. I don’t get sick, don’t get jet-lagged.”