CLINICAL INVESTIGATION Oral Androstenedione Administration and Serum Testosterone Concentrations in Young Men

ANDROSTENEDIONE IS A STE-roid hormone produced inthe gonads and adrenalglands of both sexes. It is syn-thesized from dehydroepiandros-terone and then converted to testoster-one by the enzyme 17b-hydroxysteroid dehydrogenase or to estrone by the aro-matase enzyme complex.1-3 It is cur-rently available without a prescription and marketed primarily to athletes and bodybuilders. The number of people regularly using androstenedione is not known. It has been estimated that 4.9% of male and 2.4 % of female adoles-cents in the United States have used il-legal androgenic/anabolic steroids.4 Because androstenedione is readily available as a dietary supplement, its use may be even greater. Unsubstantiated claims have been made that orally administered andro-stenedione increases testosterone lev-els and has anabolic effects in men. To determine whether androstenedione in-creases serum testosterone concentra-tions, we administered 100 or 300 mg/d of androstenedione for 7 days (vs con-trols) to young, healthy men and made detailed measurements of serum sex-steroid hormone concentrations. METHODS Protocol We studied 42 healthy paid male vol-unteers (aged 20-40 years). No sub-jects reported prior use of androstene-dione, androgenic/anabolic steroids, medications known to affect steroid hormone or binding protein levels, or participation in competitive bodybuild