Coffee

Up to 400 mg a day and 200 mg at a time for healthy adults. An is-it-a-lot table for every common dose, caffeine by drink and size from USDA data, the half-life arithmetic, the sleep cut-off by dos...

For most healthy men, coffee on an empty stomach is fine: no ulcer link, no significant reflux link. What it does change is intensity: faster caffeine absorption, a sharper cortisol response, and a...

Coffee making you tired is not one problem but four: the adenosine rebound, the sugar crash, the withdrawal loop and the sleep debt caffeine creates. Here is how to tell which crash is yours and th...