Theoretically Syntherol, when mixed in the same shot with AAS, when injected, it is a good chance that the Syntherol could 'wrap' itself around the steroid and interfere with the steroid's absobtion.
Further, if such bolus creates, the actual steroid crystals, especially if it's a suspension, could create inflamation and possible infection (the body sees it as a foreign substance) if it's in there long enough.
Keep them separate.