Fast enough to overwhelm the reductase enzyme, the thing responsible for converting Methomoglobin to hemoglobin in your body.
6 minutes? I don't know but i think faster would be better so as the bad taste doesn't linger longer. Some avoid drinking it with a straw as it takes longer time and just chug it in one go.
6 mins? It's just 50ml of water, yes it's salty no doubt but that's way too long, I'd say if you're gonna use a straw then it shouldn't take longer than a minute and a half. Getting down as much as possible in as little time as possible is crucial otherwise if you wait too long finish your first drink, you may not be able to finish it at all, let alone a 2nd one if you vomit before finishing the 1st. If it takes that long then perhaps aborting the attempt would be the best move because even if you've drank a little less than half of 50ml, your life could still be in serious danger.
