synthol is used to stretch the muscle fascia when through proper diet and training and supplementation you have met your natural limits and wish to alter, re-shape, or enlarge the muscle being injected. it is very easy to do wrong, and there are many exapmles of how bad it looks when used improperly. when used properly, it is rather painful, and the pain lingers and is constant until the course is finished. imagine your muscle like a baloon, and it is inflated to normal maximum capacity. if you put in more air, the surface of the baloon is stretched beyond it's normal limits, and is close to breaking. when that baloon surface is your muscle fascia, it litterally feels like it is tearing, ripping the fibers as it stretches. you must know exactly where to inject, how much to inject, and how often so as to keep a natural shape. if not, you will end up with a cartoon like grotesque bloated muscle that any true bodybuilder, and most other people, will find unpleasant and probably make fun of.
as to the reason behind my statement, you have not posted anything that makes me think you have already met your maximum genetic potential, I'd wager you are far from it.
you should post some pics and show us what you are working with.