It depends on urine acidity.
Higher urine acidity can stretch it to 8 hours and it holds at the peak the entire time.
Inorganic acid from things like monster, redbull, or cocacola make your urine highly acidic.
Ephedrine acts on your adrenal glandsand stimulates epinephrine response.
You get fight or flight feeling and it actually increases skeletal muscle power.
Drink a 12-20 oz redbull wait 30 min or an hour and eat four ephedrine. Drink another redbull and when you piss 30 min to an hour later your hair will stand on end and tingle. Thats the adrenal trigger.
You will continue to fly up to 8 hours if you keep your urine acidic.
Do not try this as a newb reading i am telling this to a big guy that has done this! Your heart may blow up.
I take 6 bronk and 2-3 more an hour later. It is a revved up high feeling.
It is a vaso constrictor. Your pecker will look like a baby carrot but vasoconstrictor or not your pump will be the most badass you ever saw.
It is somewhat counterproductive and very risky and hard on you. Bp will rise.
Other sides you wont find listed are swelling of the prostate. Sometimes when you are shitting semen leaks out. Literally a full load.
Ephedrine is a complex thing. It acts on your entire body in some way.