Not really what you are asking, but last night I had dinner with an old friend who is a national npc judge. The topic of synthol came up and he had quite a bit to say about it. If you plan on competing, listen to this.
It is getting so widespread that judges are finially starting to punish users through their placings in shows.
Example....a well know amature who was supposed to win his class at a recent show came in shreaded to the bone and was by far in the best shape of his class. Big full biceps when he hit a front shot, nice peak, very impressive. Then he hit a front " cross " pose. ( arms extended straight out to the side ) His bicep peak was still there !, even with his arms fully extended. It looked so obvious that they had to do something to make a point.......all the way down to 7th, one even had him last !
It is true that some get away with it and actually look very good.
Good luck in whatever you decide.