Injectable testosterone is likely to become an effective male contraceptive. Chinese researchers injected over a month, 1,045 healthy and fertile with a formula based on testosterone men.
The results, published in the Journal of Clinical Endocrinology & Metabolism, showed a failure rate of only 1.1 per 100 men over a period of 24 months, a result which is very good, since no existing contraceptive is 100% effective.
No severe side effects were observed and, after leaving the treatment, almost all the volunteers returned to a normal reproductive function. Still new safety tests are needed, but if confirmed the good results, the treatment could be available within five years, researchers assure.