YK-11 is very similar to other SARMs. Its main role is to bind itself to androgen receptors.
By doing so, the receptors will send a signal to various tissue improving the density and size of muscles. It can also work for muscle degradation and for building bones.
This is why YK 11 might become a legit medical drug in the near future, helping people who are suffering from muscle and bone conditions. The substance can also work as a myostatin inhibitor. In other words, it can provide some additional anabolic effects.
Our bodies are able to create myostatin. With this substance, you can limit your natural muscle growth. However, YK-11 blocks its production, which removes the natural barriers imposed on your body.
This is precisely why people can gain so much muscle mass in such a short amount of time; it's not that you're "pumped" with chemicals, it is just that your genetic processes are a bit altered.
https://www.hormonerawsource.com/sarm-powders/sarms-finished/stromusc-superior-quality-yk11-10mg-for.html
