The experimental male birth control pill YCT-529 has successfully passed the first phase of clinical trials in 16 healthy men aged 32 to 59 who had undergone vasectomy.[1][2][3] The pill was administered twice in increasing doses, with some participants receiving a placebo, and the men were followed for 15 days.[1] The P preparation reduced sperm production without adverse effects, including hormonal fluctuations, changes in sexual desire, mood, heart, liver, or kidney function.[1][2] It is a non-hormonal substance that blocks a receptor key to sperm production and has already undergone successful preclinical tests on mice and primates.[2][3] A second phase of testing is underway on 50 men to verify long-term safety, followed by a third phase with hundreds of volunteers to assess efficacy and side effects.[1][2] Men are interested in such contraception, so far only condoms or vasectomy were available to them.[2][3]