Does Caffeine Increase Cortisol? (According to Science)

James Cunningham, BSc, CPT
Published by James Cunningham, BSc, CPT | Staff Writer & Senior Coach
Last updated: November 25, 2023
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A morning cup of joe gives many of us that much-needed energy boost to start our day.

Although coffee is touted for its wide range of health benefits, there’s still plenty of controversy surrounding this substance, mainly because of its caffeine content.

To get the real deal on caffeine, I've spent hours researching its effects on the body, including its impact on the hormone cortisol.

Here’s what I've learned.

Quick Summary

  • Caffeine increases cortisol levels in the body, affecting brain function, heart rate, and muscle health, and may raise blood pressure and diabetes risk.
  • Consuming caffeine can disrupt sleep patterns and alter the effects of several hormones, including dopamine, adenosine, and adrenaline.
  • High cortisol levels, often caused by excessive caffeine intake, can lead to weight gain, fatigue, and increased stress.
  • In my opinion, moderation in coffee consumption is key to enjoying its benefits while minimizing negative health impacts.

Does Drinking Coffee Increase Cortisol Levels?

close up image of a woman's hand holding a white coffee mug

Caffeinated coffee can raise cortisol levels, potentially impacting brain function, muscle health, and heart rate, which may increase blood pressure and diabetes risk. Mood alterations are also a concern.

In my coaching experience, I've noticed that clients who drink caffeinated coffee often report increased stress levels.

Conversely, low cortisol levels can result in fatigue, anxiety, and emotional changes.

Most people know cortisol as the stress hormone, but it isn’t all bad. It’s the main hormone from the adrenal gland that signals your body to be responsive and awake. It also helps decrease inflammation.

In times of stress, the interplay between caffeine intake and cortisol levels becomes even more complex. Delving into how caffeine consumption during stressful periods can influence the body's cortisol production and overall stress response offers a deeper understanding of the holistic impact of our dietary choices.

Many factors contribute to elevated levels of cortisol, but taking your caffeine in moderation is one great way to keep them in check so that you can make this work to your advantage.

Related: What Are The Best Supplements to Reduce Cortisol?

Effects Of Caffeine Consumption On The Body

man holding his temples in pain, and a woman wide awake at while laying down in bed

Caffeine stays in your system several hours after ingestion, with its half-life ranging from two hours to 12 hours, depending on individual differences in absorption and metabolism.

According to Steven E. Meredith, a postdoctoral research fellow at The Johns Hopkins University School of Medicine:

“Caffeine metabolism is slower among infants, pregnant women, and individuals with liver disease. In addition, some medications slow caffeine metabolism, which may increase the risk of caffeine intoxication. But the effects of caffeine also vary simply because we’re all different.”

- Steven E. Meredith, Postdoctoral Research Fellow, The Johns Hopkins University School of Medicine

Aside from a possible cortisol surge, here are other ways that this brain-stimulating drink can affect how you function.

Short Sleep

An often-overlooked aspect of caffeine's influence on cortisol is its potential impact on sleep patterns. Since cortisol plays a crucial role in regulating sleep, understanding how caffeine-induced changes in cortisol levels might affect sleep quality and duration is vital for those looking to optimize their sleep health.

Having coffee can keep you up longer, thereby reducing the amount of sleep you get. From my own routine, I've found that drinking coffee late in the day affects my sleep quality.

This also means that you spend less time in the restorative stages of sleep, which can impair your alertness even in the morning the following day. It will impact your overall health.

Alters The Effects Of Several Hormones

sad woman hugging her pillow

Besides cortisol, caffeine can alter the effects of several hormones, including the following:


Caffeine boosts dopamine, initially elevating mood due to its stimulatory effect on the central nervous system.

However, as this stimulation wanes, it can lead to a low feeling, potentially fostering caffeine dependence.


Caffeine can hinder the absorption of adenosine, a neurotransmitter that tells your body that it’s tired. This stops adenosine from acting on your brain, making you feel alert for a time.


A drink of coffee shoots adrenaline into your system and gives you a temporary boost. However, it can make you feel fatigued, depressed and unable to deal with stress later.

Many people dealing with stress tend to counteract these effects with more caffeine, leaving them agitated throughout the day.

The Side Effects

person with a big fat belly trying to close his jeans

Weight Gain

Many experts believe that raised levels of cortisol can lead to stronger cravings for fat and carbohydrates, which can cause your body to store fat in the abdomen.

Abdominal fat carries far more health risks compared to other types of fat, so this is something you’d want to avoid.

Research published in Journal of Food Science also suggests that caffeine may diminish your ability to taste sweet flavors, thereby increasing your cravings for sugary treats [1].

The good news is that caffeine can boost your resting metabolic rate and help you burn about 30% more body fat, as long as you exercise after taking it [2].

Also, caffeine can keep your blood sugar levels raised, which will leave you feeling less hungry.


Caffeine gives cortisol and other hormones a temporary buzz, but it can leave you feeling fatigued once that buzz is gone. This is also when feelings of mild to moderate depression can set in, making physical activity more difficult.

On a positive note, caffeine has supported physical performance and endurance if not overused [3]. Combined with its fat-burning benefit, caffeine can enhance your workout and help you get in better shape if consumed properly.


Ingesting high amounts of coffee every day can lead to raised levels of cortisol, which can have undesirable consequences for your health, including chronic stress, weight gain, moodiness, elevated sugar that can cause health complications, and heart disease, according to the research published in Stress & Health  [4].

However, small to moderate amounts of this stimulant can improve your mood and provide the boost you need.

The Best Way To Drink Coffee

coffee mugs and coffee beans on a gray background

Caffeine carries potential positive and negative effects, and the only way you can truly enjoy its benefits is by taking it in controlled amounts.

Here are a few ways you can enjoy your coffee while minimizing its side effects.

Drink Coffee Before Exercise

The increased cortisol secretion from consuming caffeine can leave you feeling stressed. But if you reach for a mug of coffee in the morning before exercise, you’re likely to experience its performance-enhancing and fat-burning capabilities.

As a coach, I advise my clients to drink coffee before their morning workout. I've personally experienced the performance boost and fat-burning effects of this practice.

Related Articles:

Limit Your Caffeine Intake Levels

woman sipping coffee from a red mug

Enjoying a few cups of coffee is fine, but exceeding six cups daily could lead to long-term health issues. Staying within a limit of four cups per day, equivalent to about 400 milligrams of caffeine, or taking regular caffeine breaks, is advisable for health. In my coaching career, I've seen the negative effects of excessive coffee consumption.

Mathew Woodburn-Simmonds, founder of Home Coffee Expert, shares that it still depends on the brew methods, coffee used, as well as one’s body composition.

Opting for high-quality decaffeinated coffee is recommended for those keen on reducing caffeine intake while still enjoying its flavor. However, avid drinkers consuming more than six cups daily should be aware that cutting back might lead to withdrawal symptoms like headaches, fatigue, cravings, and muscle pain, according to the National Library of Medicine [5].

Regular caffeine consumption, through coffee, tea, soft drinks, or dark chocolate, can lead to a tolerance, particularly affecting cortisol response. Occasional caffeine intake, however, may cause a noticeable increase in cortisol levels [6].

You will still release cortisol, but not enough to wreak havoc on your system. For most people, this slight increase shouldn’t be a problem.

Time Your Coffee Intake

man sitting in a cafe looking at his watch while holding his phone

Caffeine can linger in your system for over eight hours, so it's best to drink coffee early in the day to avoid sleep disturbances. Based on my routine, I avoid coffee right after waking up and limit it to early in the day.

Avoiding coffee right after waking up is also advisable, as cortisol levels naturally peak during the early morning, typically between 8:00 to 9:00 AM.

Consuming coffee during this peak cortisol period can disrupt your circadian rhythms and potentially impact your health.

Drinking coffee unnecessarily can reduce its stimulative effectiveness and accelerate caffeine tolerance, lessening the energizing effect. Cortisol levels peak again around midday and early evening, so it's best to avoid coffee after 2 PM.

Ideally, enjoy your first cup in the late morning, between 9:30 and 11:00 AM, when cortisol levels start to drop. If you crave coffee in the afternoon, consider opting for decaf to avoid disrupting your sleep cycle.

Rob O. of coffee site Above Average Coffee, shares that at the end of the day, it is also important to notice and consider your personal response to caffeine intake so you can adjust your caffeine habits.


How Can I Reduce My Cortisol Levels Quickly?

You can reduce your cortisol levels quickly by eating healthy food - a balanced diet that includes bananas, pears, probiotics, green tea, and drinking plenty of water.

Sleeping well, practicing relaxation techniques, exploring a new hobby, listening to calming music, taking fish oil and ashwagandha supplements, and exercising have also been shown to help reduce measured cortisol levels.

What Foods Increase Cortisol Levels?

Foods that increase cortisol levels include coffee, trans fats, saturated fat from animals, refined sugar, alcohol, refined grains, and foods low in fiber.

Is Caffeine Bad for Your Adrenal Glands?

Caffeine is bad for your adrenal glands only if you consume too much.

High levels of caffeine in your system leads to poorly functioning adrenal glands that can damage the immune, neurological, cardiovascular, and endocrine systems.


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