Many physical problems like that would be better left to going to a doctor over. Once a doctor determines the cause of ED, and gives you a treatment plan, then you can consider a spell that would help aid whatever treatment your doctor prescribes. But as I said keep in mind for any situation look for a way to try to solve the problem without a spell, or by using a spell to aid in the solution. Think or spells as a booster shot. A booster shot aids in helping the immune system but without an immune system there is no need for the booster shot. The same with spells unless you are willing to try and solve the problem without a spell then what is the point in using a spell?