I asked Dr. Jay Hoffman, Professor and Chair of the Department of Health and Exercise Science at the College of New Jersey, about the theory that sports supplements are a gateway to anabolic steroid use. He replied in an email:
I do not believe that this is the case. There really isn’t any documented evidence to support such a claim. Although all anabolic steroid users I would venture to guess use sport supplements – I do not necessarily support the hypothesis that increasing supplement use would increase anabolic steroid use.
Furthermore, he told me that steroid education programs are critical in high schools address the confusion regarding steroids and supplements:
These educational programs need to first involve educating coaches and athletic directors concerning realistic expectations from training programs and the risks and benefits of anabolic steroids and when supplements could be considered (they do not go hand-in-hand with the onset of training programs that unfortunately too many uneducated coaches appear to stress) and then educating the adolescent athlete.
We need to remember that steroid education involving coaches is also important at reducing steroid use in high schools.