The Effects of Androstenedione Supplementation on Serum Gonadal Hormones

Abstract

Objective: To review the effects of androstenedione supplementation on serum gonadal hormones. Data Sources: Biomedical literature was accessed via PubMed through September 2007; MeSH terms included androstenedione and gonadal hormones. Study Selection and Data Extraction: Studies were limited to those published in English, with the primary outcome of change in serum gonadal hormone concentrations following multiple-dose oral androstenedione supplementation. Articles that reported only effects on muscle strength were excluded because our review focuses on the biochemical, not physiological, effects of androstenedione. For studies that evaluated multiple outcomes of therapy that were published in more than one journal, only the article reporting serum gonadal levels was selected for this review. Data Synthesis: We reviewed 8 unique studies that evaluated the effect of oral androstenedione supplementation on serum gonadal hormone concentrations. Critical comparison of the studies is challenging due to heterogeneity in methodology and outcomes measured, small sample sizes and short durations, and lack of complete data. The timing of serum gonadal hormone measurements, which is of critical importance, is not standardized among the studies. Subjectively evaluated, these studies suggest that androstenedione supplementation may cause a small, transient increase in serum testosterone. However, this effect is very short (<24 h) and may be completely negated by conversion to estrogens and through feedback inhibition of endogenous testosterone production with long-term use (≥28 days). Conclusions: The findings of the studies reviewed suggest that androstenedione supplementation may cause a small, transient increase in serum testosterone levels. More importantly, estrogen-related hormones were also increased. Although androstenedione supplements are no longer available in the US without a prescription, they are available in other countries and potentially via the Internet. Clinicians should be aware of the potentially harmful effects of androstenedione on gonadal hormones in the event that they are involved in the care of a patient who may be using an androstenedione-containing product.