How do I know if I'm suffering from ED or low T?

ED. TimV ~ T can be very quickly and easily done by blood test. LOW T VERY SELDOM causes ED. You are getting ED because you're 46 ! Incidence at 40 about 25/1000man years and increases by 50% every decade. Currently about 620 000 men with ED in USA today. I never do T levels for that. I do treat it with vasodilators (Viagra) etc. See your doc. thx.