Waking up with a headache depends on 1. How much you drink, and 2. How much water you're drinking while you're indulging. You could drink a whole bottle of this stuff, and as long as you stay properly hydrated, you're not gonna have a headache. The whole reason for headaches after booze, is that booze dehydrates you. Drink 10oz of water for every hour you're drinking and you'll thank me! I haven't had a hangover headache in YEARS!