I do believe synthol can be used without adverse effects. Over a long period of time I guess it would gradually be broken down and excreted. I read a article on MD before about mixing synthol with anabolics.
people can rationalize anything apparently.
I don't even use IM shots anymore, Korean 'muscle reduction' surgery involves sticking needles into women's muscles to sever the nerves, which results in the muscles (usually calfs and quads) shrinking down to a 'fashionable' size. I suspect this is why many older bodybuilders have 'old dude triceps' - they destroyed the nerves with repeated sticks
slicing nerves and scar tissue accumulation from years of 'site injects' is going to wreck your body eventually, so adding synthol to the mix is beyond insane imo