Does Caffeine Increase Cortisol? (According to Science)

James Cunningham, BSc, CPT
Published by James Cunningham, BSc, CPT | Staff Writer & Senior Coach
Last updated: March 29, 2024
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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.
  • Research published in the Journal of Food Science indicates that caffeine consumption may reduce the sensitivity to sweet flavors, potentially leading to heightened cravings for sugary snacks.
  • 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.

“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:

Dopamine

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.

Adenosine

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.

Adrenaline

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.

Fatigue

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.

Stress

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 generally okay, but going over six cups a day can cause long-term health issues. It's best to stick to a maximum of four cups, around 400 milligrams of caffeine, or to take breaks from caffeine. In my experience as a coach, I've seen the drawbacks of too much coffee.

As Home Coffee Expert founder Matthew Woodburn-Simmonds points out, the effects can vary based on brewing methods, coffee type, and individual body composition.

For those wanting less caffeine but still craving coffee, high-quality decaffeinated options are a good choice. However, heavy drinkers should be mindful of potential withdrawal symptoms like headaches and fatigue, as noted by the National Library of Medicine [5].

Regularly consuming caffeine from coffee, tea, soft drinks, or dark chocolate can build tolerance, especially affecting cortisol response. But infrequent use may spike cortisol levels [6]. This cortisol release is usually harmless for most people, not causing significant disruption to the body's system.

Time Your Coffee Intake

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

Caffeine stays in your system for over eight hours, so drinking coffee early is wise to prevent sleep issues. I skip coffee right after waking up, aligning it with my daily schedule.

It's also smart to avoid coffee first thing in the morning, as cortisol, the stress hormone, naturally peaks around 8:00 to 9:00 AM. Drinking coffee during this time can disturb your body's natural rhythm and affect your health.

To maintain its stimulating effects and prevent building up a tolerance, avoid coffee during cortisol's midday and early evening peaks, especially after 2 PM. The best time for your first cup is late morning, between 9:30 and 11:00 AM.

For afternoon cravings, decaf is a good alternative. Rob O. from Above Average Coffee reminds us to pay attention to our personal caffeine responses and adjust accordingly.

FAQs

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.


References:

  1. https://onlinelibrary.wiley.com/doi/abs/10.1111/1750-3841.13836
  2. https://jissn.biomedcentral.com/articles/10.1186/s12970-020-00400-6
  3. https://link.springer.com/article/10.1007/s40279-014-0257-8
  4. https://onlinelibrary.wiley.com/doi/abs/10.1002/smi.2486
  5. https://www.ncbi.nlm.nih.gov/books/NBK430790/
  6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2257922/
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About The Author

James Cunningham, BSc, CPT
Staff Writer & Senior Coach
James Cunningham, BSc, CPT holds a BSc degree in Sport & Exercise Science from University of Hertfordshire. He's a Health & Performance Coach from London that brings a unique blend of academic knowledge of health supplements and practical exercise experience to the table for his readers.
Learn more about our editorial policy
Dr. Harshi Dhingra, MBBS, MD is a published peer-reviewed author and renowned physician from India with over a decade of experience. With her MBBS from Bharati Vidyapeeth and an MD from Rajiv Gandhi University, she actively ensures the accuracy of online dietary supplement and medical information by reviewing and fact-checking health publications.
Learn more about our editorial policy
Dr. Kristy June Dayanan, BS, MD is an author with a BS degree from University of the Philippines and an MD from University of Perpetual Help System. Her ability to simplify medical science complexities and dietary supplement jargon for the average reader makes her a valued medical fact checker and reviewer.
Learn more about our editorial policy

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