For years, coffee was widely believed to be dehydrating due to its caffeine content, which acts as a mild diuretic; stimulating urine production and, supposedly, fluid loss. This perpetuated the myth that coffee couldn’t count toward daily hydration. However, more recent research has debunked that notion: studies show that regular coffee drinkers develop a tolerance to caffeine’s diuretic effects, and that well, coffee is mostly water so it contributes to overall hydration. Today, many health experts recognize that moderate coffee consumption does not dehydrate you. So your morning brew isn’t just a wake-up call; it’s hydrating too.