I just take aspirin, aceteminaphene or advil when I have a headache even when water fasting. I know some people don't like to take anything, but I'd rather take some pill than put up with the headache. Same with heartburn/antacid medication, I take tums for that. No need to put up with negative effects from detoxing during fasting. Right now I'm lucky and haven't had a headache yet (beginning of my Water Fast that is).