Have prohibition policies made the wrong decision? A critical review of studies investigating the effects of DMAA

In June 2012 DMAA (1,3-dimethylamylamine), an ephedrine-like vasoconstricting substance which had been included in many popular sports supplements, became a scheduled substance in Australia, following bans in several other countries. The underlying rationale for this ban was that DMAA use is unsafe. This paper aimed to critically review the available evidence on the acute and/or long-term harms of DMAA. Using five research databases (PubMed, Embase, ProQuest Health and Medical Complete, and Web of Science) and the key terms 'methylhexaneamine', 'DMAA', 'dimethylamylamine', '1,3-dimethylpentylamine' and '2-amino-4-methylhexane', 842 articles were identified once duplicates removed. Sixteen studies met the inclusion criteria and were included in the review. Of the included studies, eight were case studies, which reported on eight patients who presented to emergence departments. All were retrospective in their reporting. The patients displayed various outcomes; while the patients were presenting with serious problems, in most patients conditions subsided on cessation of supplement use. The remaining eight experimental studies were low powered, with a number of studies conducted by a single research group with industry ties, and broadly investigated the effects of DMAA on physiological outcomes. Mixed findings were apparent, although escalations of blood pressure were present on acute dosing, as well as decreases in measures of body weight and body fat. There is a shallow evidence base describing the adverse effects of DMAA and the dose above which such effects may occur. The scheduling of DMAA in many countries may now impede research efforts to determine whether there are safe doses at which DMAA can be consumed.