Researchers at the Los Angeles Biomedical Research Institute are working on a male contraceptive pill, which has just passed the safety tests (phase I clinical trial). The data was presented at ENDO 2019, the annual meeting of the American Society of Endocrinology. This is an oral pill consisting of 11β-MNTDC , which is first metabolised into 11β-MNT  and then reduces gonadotropin production .
The study looked at 40 healthy volunteers for 28 days: 10 received a placebo, 14 received a daily 200-mg dose and 16 received a daily 400-mg dose. After 24 hours, testosterone levels in the 30 men undergoing treatment had already dropped significantly, with no notable side effects such as erectile dysfunction. Testosterone levels had fallen to the same level as in patients with androgen deficiency, and were even twice as low in volunteers who took their dose at mealtimes.
The researchers nevertheless pointed out that “an observation period of 28 days is too short to observe an effective decrease in sperm production, which normally occurs after 60–90 days of low androgen hormone levels”.
For further reading:
 11β-methyl-19-nortestosterone 17β-dodecylcarbonate
 A hormone that controls spermatogenesis