Should You Drink Water Before Your Morning Coffee? What Experts Say

Many people have been told that starting the day with water instead of coffee can improve hydration and help regulate stress hormones. But experts say the science behind delaying your morning cup is far less convincing than social media suggests.

A recent social media trend suggests drinking water one or two hours before sipping your first cup of coffee helps improve hydration and balance cortisol levels. Fact or myth? Here’s what science says.

Experts believe staying hydrated in the morning is important, but there’s no strong evidence that waiting to drink coffee offers extra health benefits. Let’s break it down.

Why Hydration Matters in the Morning

It’s normal to wake up slightly dehydrated after a full night’s sleep without drinking fluids. The human body, which is made up of more than 50% water, typically loses 400 to 700 milliliters (or about 1.5 to 3 cups) of fluid overnight.

“Drinking water after waking helps reverse overnight fluid loss and supports normal physiology, including mood and perceived fatigue when mild dehydration is present,” says Lynette Gogol, DO, a board-certified neurologist and lifestyle medicine physician.

But hydration needs vary from person to person. In fact, there is no strong evidence supporting the eight-glasses-a-day rule.

According to experts, fluid needs depend on a person’s body size, activity level, and temperature. What matters most is recognizing when you’re thirsty and responding to it.

“If you get thirsty, drink water. If you're not thirsty, you don't need to drink water,” says Tamara Hew-Butler, associate professor of exercise and sports science at Wayne State University.

It’s also important to note that older adults may have a reduced sense of thirst and may need to be more intentional about drinking fluids.

Does Coffee Dehydrate You?

It’s a common belief that coffee causes dehydration, which is one reason some people suggest drinking water before coffee. But research does not support that idea.

Scientific studies show that coffee contributes to fluid balance and does not lead to dehydration when consumed in moderation.

Coffee is composed of more than 95% water. Studies comparing coffee drinkers to those consuming equal amounts of water found no significant differences in hydration status.

NPR reports similar findings. While caffeine can act as a mild diuretic in large amounts, caffeinated drinks consumed in moderation provide the same hydration as non-caffeinated drinks.

In regular coffee drinkers, the fluid in coffee offsets its mild diuretic effect.

What About Alertness and Cortisol?

Some influencers also claim drinking coffee immediately after waking spikes cortisol and disrupts energy levels.

Cortisol naturally rises within 30 to 45 minutes of waking, and caffeine can stimulate cortisol production. However, in people who regularly drink coffee, the body adapts without evidence of lasting harm.

There is also no strong evidence that drinking water before coffee enhances caffeine’s effects. “Caffeine is rapidly and reliably absorbed after oral intake, and there is no evidence that pre-hydrating hours earlier makes caffeine inherently more potent,” says Dr. Gogol.

Hydration can affect mood and cognitive performance when someone is mildly dehydrated. But there is no evidence that drinking water before coffee provides special cognitive advantages compared with drinking the same amount of water later.

The bottom line is this: While drinking water in the morning is a healthy habit, for most adults, coffee also counts toward daily fluid intake. There is no strong evidence that you need to wait an hour or two before having your morning cup.

As hydration experts describe it, balance is key — not too much, not too little.