Mass 550 contains natural ingredients that are scientifically proven, so you don’t have to worry about any serious side effect because nor has been recorded yet. In case a side-effects do develop, it is very advisable to discontinue the use of this product or consult a medical doctor. There are a lot of positive feedback about Mass 550 with only few complains been made regarding the use. Some users reported to have feel more hungry than before and also that they feel a pretty dry effect and ache on the joints especially on their shoulders. Others start to experience this ache on their shoulders after three weeks of using Mass 550.