synthol, if used properly and not abused can help bring up lagging muscles but i would not ever recommend anyone use it. to many risks involved such as getting an infection from an unsterile product, getting an abcess from injecting to much at a time, severely distorting the muscle (example would be the flat spot on top of valentines one bicep) etc. you must also be well versed in where to inject since it should only be injected in small muscle groups and most of them have multiple muscle heads and you would need to hit each one evenly.
like chris 1 said, you would be better off spot injecting some test into a lagging muscle than using synthol. a little test suspension will do wonders for increasing muscle size
