Well, the cons are, I would look like a junkie, because I take several doses of growth a day! I've seen a chart showing that there is a faster spike using IV, but it just isn't worth it. IM is great and it's easy, giving sustained release. Good consistent levels of IGF and no added issue. When you start injecting directly into the blood stream, there is going to be more chance of blood infections, not to mention, the damage you'd do to your veins after daily IV shots.