By STEVE WILSTEIN

© The Associated Press

Now that Mark McGwire has joined the elite 500-homer club after saying no to andro, doctors are hoping sales of the supplement will slide.

``The message Mark McGwire sends to our young people by walking away from this substance is a powerful one,'' Barry R. McCaffrey, the White House drug policy director, said Thursday.

``We all need to be aware that just because a superstar stops using andro, the problem doesn't just go away. Countless young people still take this potentially dangerous substance - banned by the NFL, the Olympics, the NCAA and professional tennis - in order to improve their athletic performance. We must continue to focus on the risks at hand.''

In the year that has passed since The Associated Press reported that McGwire was using androstenedione during his 70-homer season, sales of the testosterone booster surged more than 1,000 percent to more than $50 million, according to industry figures.

Easy access to the over-the-counter supplement through the Internet and nutrition stores worried doctors that thousands of young people might be risking long-term illness. Andro manufacturers say more than 100 players in the majors and minors are using the supplement, which converts to testosterone in the body and is considered an anabolic steroid by most steroid specialists.

McGwire said he was unhappy being cast as the poster boy for andro, even though he wasn't breaking any baseball rules. He said he hasn't used andro in four months, and will never again take it.

``I still believe there's nothing wrong with it,'' he said in St. Louis before hitting homers No. 500 and 501. ``But if I have a message for kids, it's that you don't necessarily have to follow what somebody who's in the public eye does. If you're an adult, you elect to choose your own destiny.''

McGwire didn't explain why he waited four months to say he was dropping andro if he wanted to send out the message to youngsters. When he arrived in spring training, he adamantly said he would continue using the supplement.

``That's four months' worth of kids who took andro because of him,'' said Dr. Gary Wadler, a leading steroid specialist at NYU Medical School and a consultant to several professional sports. ``I'm delighted he said it today, rather than never saying it at all, but I would have preferred he said it at the beginning of the season.''

Dr. Wade Exum, head of the U.S. Olympic Committee's drug control program, also applauded McGwire's announcement.

``I think it's great,'' Exum said. ``I can't say it'll help tremendously because it's somewhat after the fact. But if he's not using the stuff, and he's still having a hell of a season, then maybe the message will counterbalance some of the things that went on last year. The problem is, after last year, the sales of that stuff jumped. All you can do now is follow the sales and see if they go down.''

McGwire's use of andro through the winter and spring training, though, may have given him a competitive edge that would help him during the season.

``That's the whole basis for year-round, out-of-competition testing,'' Wadler said. ``People in other sports were very savvy to announced drug testing, so what they did was take a lot of this stuff, bulk up, and when the season started they stopped. They continued to work out and derive much of the benefit.''

An Iowa State study of andro published a few months ago showed that in small doses, andro didn't increase strength, but still might lead to heart disease and other health problems.

``The problem with that study is that is not how people tend to use these things,'' Wadler said. ``They usually take many multiples of the recommended daily dose, 10 to 100 times what's on the label. Anybody who thinks people taking andro with the eye toward improving performance or developing musculature are not taking multiples is kind of putting their head in the sand.

``If he took a lot, and he took it many times a day, and he did it for a long time, he could derive the benefits, which is increased muscle mass in conjunction with weightlifting, and he could have a carryover through the season.''

The bigger problem for baseball, Wadler said, is the issue of whether andro is just a tiny part of anabolic steroid use.

``It's time now for baseball to step up to the plate. Baseball needs to get its act together and stop nipping around the edges. It has to get to the heart of the matter.''

That, Wadler said, involves banning andro and similar substances, and testing for the whole range of anabolic steroids.

``Do I think baseball has steroid abuse in it? If it didn't, it would be the first sport that we know of at a high level where there was no steroid use,'' Wadler said. ``There may not be a whole lot of people, but to think they're immune from the behaviors that we see in all kinds of other sports is the ultimate of naivete.''

Meanwhile, neither baseball commissioner Bud Selig nor union officials have shown a willingness yet to ban andro or test for anabolic steroids. A Harvard study of andro, commissioned by baseball, is still months from release, and no decision is expected before that.

Selig on Wednesday declined to talk about McGwire's decision, but NL president Len Coleman praised the Cardinals' first baseman's act.

``Mark's focus is on contributions to society,'' Coleman said. ``He leads by example. The youth of the world are well served by Mark's value structure.''