Washington, May 5 (Inditop) Injectable testosterone could be the way to male contraception, that is effective, reversible, and minus serious short-term side-effects, according to a new study.

“For couples who can not, or prefer not to, use only female-oriented contraception, options have been limited to vasectomy, condom and withdrawal,” said Yi-Qun Gu, National Research Institute for Family Planning (NRIFP) in Beijing.

“Our study shows a male hormonal contraceptive regimen may be a potential, novel and workable alternative,” he added.

Gu said this study is the largest multi-centre, male hormonal contraceptive efficacy clinical trial of an androgen preparation in the world.

Participants included 1,045 healthy fertile Chinese men aged between 20-45 years. Each participant had fathered at least one child within the two years before the study and had a normal medical history.

Their female partners were between 18 and 38 years of age and had normal reproductive function.

Males were injected monthly with 500 mg of a formulation of testosterone undecanoate (TU) in tea seed oil for 30 months. Results showed a cumulative contraceptive failure (pregnancy) rate of 1.1 per 100 men in the 24-month efficacy phase.

No serious adverse events were reported and reproductive function returned to the normal fertile reference range in all but two participants, said a NRIFP release.

“Despite the present encouraging results, the long-term safety of this hormonal male contraceptive regimen requires more extensive testing with a focus on cardiovascular, prostate and behavioural safety,” said Gu.