It says zero side affects. Everything has side affects. It seems pretty potent to only take once a month or once quarterly so I wonder if it would make you sterile after a while..... Honestly I'd rather just get a vasectomy, but I'm sketchy about new drugs especially when thy seem "perfect".
"What we found is that by treating the mice with our molecule..."
If everything that was effective in mice were effective in humans we would be in a utopia like medical environment filled with sunshine and rainbows (hint: we're not).
Trestolone (MENT) is also being developed as a contraceptive. Said to be highly suppressive, and the fact that it almost requires the use of an AI may limit the potential there.