Most of us have a problem with synthol users if the purpose is to make fake muscles.
However, there is one legitimate use. Our muscles are contained in a membrane like tissue called the fascia. It's like the lining of the sections of an orange. If you have tight fascia by genetics, you will have a harder time gaining muscle. The genetically gifted have more flexible fascia. Using synthol in a one time cycle to stretch the fascia of a stubborn muscle group is acceptable......at least to me.
The purist can do the same thing by site injecting high oil volume steroids like ganabol50.