President Bush signed a law on Friday banning certain steroid-like drugs, used by some athletes as performance enhancers.

The new law adds 18 substances to the list of banned anabolic steroids, including androstenedione, also known as “andro,” which was made famous by baseball slugger Mark McGwire in the 1990s.

When injected, these substances metabolize into testosterone or other illicit steroids, and federal regulators have been seeking to crack down on the makers of these drugs.

“Steroid use by young people is a serious health issue,” said Sen. Joseph Biden, who crafted the measure.

“This new law sends a strong message about andro and other steroid precursors. We are calling them what they really are: drugs, performance enhancing drugs,” the Democrat from Delaware said.

The newly signed “Anabolic Steroid Control Act of 2004,” also requires a review of federal sentencing guidelines for offenses involving anabolic steroids. It calls for criminal penalties for those caught making, selling or possessing the substances.

The new law also provides $15 million for education programs to teach children about the dangers of steroids.