To determine the safety, tolerability, pharmacokinetics, and pharmacodynamics of oral DMAU, researchers conducted a 28-day, double-blind, placebo-controlled study in which 82 healthy men between the ages of 18 and 50 years were randomly assigned to receive an active daily oral dose of 100 mg, 200 mg, or 400 mg of DMAU in castor oil; 200 mg or 400 mg of DMAU in powder form; or placebo. The researchers found no significant differences in baseline characteristics across the 6 treatment groups.
Each participant underwent 24-hour pharmacokinetic blood sampling on days 1 and 28, as well as twice-weekly ambulatory visits for the duration of the treatment. Primary outcomes were safety and tolerability parameters such as vital signs, mood, sexual function scores, and adverse events. Secondary outcomes included pharmacokinetic profiles and pharmacodynamic effects on gonadotropins and sex hormones.
Mixed model analysis revealed DMAU had a significant impact on sexual desire (P =.009), yet there were no statistically significant changes in sexual activity (P =.97), erectile function satisfaction (P =.93), or mood in any treatment group (P =.99).
All participants who received 400 mg of DMAU in powder form and 92% of those who received 400 mg DMAU in castor oil experienced significant suppression of serum levels of luteinizing hormone, follicle stimulating hormone, and testosterone by 28 days. The researchers also noted a significant dose effect on weight, hematocrit, and high-density lipoprotein cholesterol measurements and corrected QT interval; serum 24-hour average concentrations of DMAU and dimethandrolone also showed dose-related increases (P <.001).
There were no serious adverse events reported. Headache was the most common adverse event, with additional moderate or mild cases of decreased libido, erectile dysfunction, and acne.
Certain limitations were noted for this study, including lack of data for long-term safety and efficacy, as well as uncertainty over whether weight gain experienced by some participants was lean or fat mass.
Despite such limitations, the researchers said their results confirm that “daily oral administration of DMAU for 28 days in healthy men is well tolerated. Doses of ≥200 mg suppress serum [testosterone], [luteinizing hormone], and [follicle stimulating hormone]; properties consistent with an effective male contraceptive without significant changes in sexual function or signs of liver toxicity.”
Thirumalai A, Ceponis J, Amory JK, et al. Effects of 28 days of oral dimethandrolone undecanoate in healthy men: A prototype male pill [published online September 24, 2018]. J Clin Endocrinol Metab. doi:10.1210/jc.2018-01452