Sir Foxx said:Its not a side effect of the actual supplement, its a side effect of getting bigger. Your muscles are larger now and positions that use to not do this, now do due to the larger muscles pressing and squeezing blood vessels. My lifting partner started getting this last year after he finally got serious about lifting.
DrDunc33 said:Actually, it is when the blood supply gets cut off. The lack of oxygen makes the arm go numb. If you lay funny on your arm during sleep, the pressure on the axillary arteries doesn't allow new oxygenated blood to enter the arm and hand, thus they start to go numb.
Matthew D said:No, it is the small blood vessels called capillaries that are getting thier blood flow reduce. The blood suppy is not entirely cut off just a reduction of the supply of blood to the area. The nerves are the first to feel it because they need the most oxygen of all the different types of cells.