Does Coffee Raise Cortisol?

Yes, the caffeine in coffee raises cortisol, but less than you might think if you drink it every day. In controlled studies, caffeine caused a clear cortisol rise in people who had gone without it. In daily drinkers, the morning dose barely moved cortisol, though a second dose later in the day still did.

Cortisol gets blamed for a lot online, so it's worth separating what the studies measured from what gets claimed. Below is how much caffeine affects cortisol in different situations, what happens around exercise, and what the popular advice to delay your first coffee is actually based on.

How Much Does Caffeine Raise Cortisol?

It depends mostly on whether you're used to caffeine. After several days without it, repeated 250 mg doses of caffeine raised cortisol clearly throughout the day. In people taking caffeine daily, the first morning dose had little effect, while a second dose in the afternoon raised cortisol again.

The best data comes from a 2005 study in Psychosomatic Medicine of 96 healthy men and women. Each person spent five days on caffeine capsules of 0, 300 or 600 mg a day, then took 250 mg doses at 9 a.m., 1 p.m. and 6 p.m. while researchers tracked cortisol in their saliva.

The researchers concluded that cortisol responses to caffeine "are reduced, but not eliminated" in people who consume it daily. Note that the study used caffeine capsules rather than brewed coffee, so it isolates caffeine itself.

Does Your Body Get Used to the Cortisol Effect?

Partly. Regular caffeine use builds a tolerance that blunts the cortisol rise, especially from your first cup of the day. That tolerance isn't complete, though. Stacking more caffeine later in the day, or coming back to coffee after a break, brings the cortisol rise back.

That pattern matters more than any single number. In the 2005 study, just five days of regular caffeine was enough to blunt the morning response. If you drink one or two cups every morning, that data suggests your morning coffee does little to cortisol. The habits that raise it more are large or repeated doses spread through the day, and a big cup after a week or more without caffeine.

Tolerance cuts both ways. The same blunting that keeps your morning cup gentle is part of why regular coffee feels less powerful than it did when you started. Our guide on how long caffeine lasts covers how your body clears it.

Should You Wait 90 Minutes to Drink Coffee After Waking?

There's no good evidence you need to. The idea is that cortisol naturally peaks soon after waking, so coffee during that window is wasted or harmful. Cortisol does rise sharply after waking, but no controlled study has shown that delaying your first coffee improves energy, cortisol or health.

The natural morning rise is real and well studied. A 2025 review in Endocrine Reviews describes it as a rapid increase in cortisol over the first 30 to 45 minutes after waking, which likely helps prepare your body for the day. Most of your daily cortisol is released in the hours around waking.

What's missing is a trial of the 90-minute rule itself. And for daily coffee drinkers, the 2005 study suggests the morning dose barely affects cortisol anyway. If waiting suits you, that's fine. If you'd rather have coffee right away, the research gives you no reason to stop.

Does Coffee Before a Workout Raise Cortisol?

Yes, somewhat. Exercise and caffeine together raised cortisol more than exercise alone in a controlled study. The clearest effect on a workout came at a very high dose: about 800 mg of caffeine before lifting raised cortisol by about half. At normal doses, the rise was small or unclear.

In a 2006 study by the same research group, moderate exercise on its own didn't raise cortisol, but caffeine taken beforehand did, in both men and women. Caffeine also added to the cortisol rise from mental stress.

A 2008 study of 24 professional rugby league players tested 0, 200, 400 and 800 mg of caffeine an hour before resistance training. The 800 mg dose, about double the FDA's daily guide, produced a moderate 52% rise in cortisol. That's far more than you need for a performance boost, as our guide on drinking coffee before a workout explains.

The same study found caffeine raised testosterone too, by about 21% at the top dose, while the ratio of testosterone to cortisol dipped slightly. The authors suggested the two effects might offset each other. No study has shown that either change affects muscle gains from a normal cup of coffee, and short hormone spikes after lifting don't predict growth either; see does lifting weights increase testosterone.

Is a Coffee Cortisol Rise Bad for You?

Not clearly. Cortisol is a normal hormone, and short rises happen every day with waking, exercise and stress. Research hasn't shown that the brief rises from moderate coffee drinking harm healthy people. Studies on whether regular coffee drinkers react differently to stress have also reached mixed results.

A 2024 study in Psychosomatic Medicine of two groups of young adults found that habitual caffeine users had bigger cortisol responses to a lab stress test. But a 2024 study in BMC Psychology found no difference in cortisol responses between men who drank no coffee, a little or a lot. That one had just 16 men per group.

The FDA cites up to 400 mg of caffeine a day as an amount not generally linked to negative effects in most healthy adults. If you're pregnant, have anxiety or a heart condition, or take medication, ask your doctor what's right for you.