Scientists are tinkering with several other strength shortcuts. Two excite the iron-pumpers most.

1) GHRH (growth hormone-releasing hormone). Human growth hormone (HGH), which stimulates muscle growth, is now widely abused by weight lifters and bodybuilders. GHRH is one step back up the manufacturing line. It may work better and be harder to detect than HGH. GHRH signals the pituitary gland, triggering production of growth hormones. In one study, piglets dosed with GHRH grew nearly 40 percent bigger and lost 10 percent of their fat. But GHRH has not been tested on humans, and its effectiveness and its side effects are unknown.

2) Myostatin. The leading expert on sports enhancement, Dr. Gary Wadler of NYU Medical School, has suggested that a compound called myostatin might be abused by athletes (and enhancers). Myostatin is a naturally occurring molecule that inhibits muscle growth. Wadler says that mice and cattle engineered without myostatin have significantly more muscle mass than normal animals. It's possible that scientists might alter human myostatin production to build strongmen. As with GHRH, the risks and benefits are a black hole.