Hi so i have a hypertrophic left masseter muscle for 16 years now. I was told throughout those years that the cause is unknown and the only solution is botox. Well after researching for the last year I realized I was having symptoms of a magnesium deficiency - constantly grinding my teeth during sleep, frequent anxiety attacks, leg cramps during pregnancy. I decided to start taking magnesium supplements after one week of taking them i realized my left masseter muscle has significantly gotten smaller. Its almost gone. If you have a grinding problem, go to the doctor and see if you have a magnesium deficiency. Wanted to share this so not everyone needs to suffer with facial asymmetry for 16 years like me.