This is a very good question. Because of the official Phase 0 status there are no measured side effects until now. We can only speculate - of this and of further possible side effects.
Even derivatives may have changed effects regarding to its "mother"-substance.
The only thing I red about YK-11 users:
- rapid increase of power
- some got acne (shoulders, back, face), but it seems not that harsh
- high blood pressure
But even these logs are very new. I will post bloodworks if I get/find any (only the legit ones).
More interesting is the "longer-term" usage of YK-11: when a very small amount of it (500nmol, if I remember right) can lead to higher follistatin values - and therefore decreased myostatine values - what's the effect of 1-max. 2mg/ed over 10-16 weeks?
If the side effects are low - especially liver values - and a usage of more than 10 weeks appropriate, every steroid user will have an added benefit of that YK-11. Imagine the possibilities of decreased myostatine over a longer period: the gains are more sustainable. Four weeks are nice but you know what I mean. Actually, until there are nearly no blood values out there I wouldn't recommend to use it more than four weeks (stay safe!).
PCT with a SERM is a must, because of it's structure it may lead with high probability to a shutdown.
Furthermore, if you compare YK-11 with Progesterine you will notice furhter similarities. It also could be that YK-11 will affect the progesterone value - either in positive or negative way, we don't know (IF so).
It's like to pick up a pill from the streets - or from Morpheus, like in Matrix with that blue and red pill - and waiting, what will happen next. The only thing you know: it's a derivative from a prohormone - therefore this name "pro", the preliminary stage to a hormone - like from DHT or another one and that it will affect somehow in some way your muscle mass. And that it will increase follistatine, which will e.g. itself increase the prostata. There are sooo many gears in this whole system, so I appreciate every bloodwork from every brave guinea pig
It's not known when the Phase I studies start.