Yak, it can make a permanent difference if used correctly. It will make the muscle fascia stretch. If used correctly and for a long enough period of time, as it is absorbed, muscle can grow in its place. How long this will work is really unknown. If you use a lot of it, obviously, as it is absorbed, the muscle will shrink, but some muscle should grow in its place. I preffer site injections to SEOs, but I might think about it in the future. Later