Enjoying this article?

Join our newsletter

Understanding Caffeine Sensitivity: Exploring Genetic Factors, Liver Health, Stress, and Habituation

Understanding Caffeine Sensitivity: Exploring Genetic Factors, Liver Health, Stress, and Habituation

At Exhale we sincerely believe that coffee can be healthy. Just check out some of my other articles to read the zillions of studies supporting this belief. But more than just sourcing, roasting and then selling ridiculously healthy coffee, we’re passionate about educating the world on how to have a healthy relationship with coffee. Because that’s equally as important.

You can’t just switch from a run-of-the-mill coffee to a ridiculously healthy coffee and expect it to change your life if you’re still mis-using it… coffee contains caffeine which is a psychoactive drug and should be respected!

Central to having a healthy relationship with coffee is understanding how your body interacts with caffeine.

Exhale Healthy Coffee - Caffeine Sensitivity Article Image 1

In this blog, we dive into the fascinating world of caffeine sensitivity. We'll explore various factors that can influence your individual response to caffeine, including genetics, liver health, stress levels, and habituation.

So, grab your favourite brew, relax, and let's dive in!

How do your genes affect your caffeine sensitivity? Including the CYP1A2 gene and the ADORA2A gene.

Genetics play a significant role in determining your default response to caffeine. Two key genes associated with caffeine sensitivity are CYP1A2 and ADORA2A.

The CYP1A2 gene encodes an enzyme responsible for metabolising caffeine in the liver. Variations in this gene can influence the speed at which your body breaks down caffeine. If you have a slow metaboliser variant, caffeine may stay in your system longer, leading to increased sensitivity and a higher risk of experiencing jitters or anxiety. On the other hand, if you have a fast metaboliser variant, you may process caffeine more efficiently, experiencing fewer adverse effects.Exhale Healthy Coffee - Caffeine Sensitivity Article Image 2

The ADORA2A gene affects the adenosine receptors in your brain, which play a role in regulating alertness and sleep-wake cycles. It’s caffeine’s interaction with these adenosine receptors that cause caffeine to make you feel more alert and less tired.

One variant of the gene may cause some people to have a higher number of adenosine receptors, making them more sensitive to caffeine's stimulating effects. It’s these people who feel more of a spike from caffeine and are more likely to feel caffeine jitters or anxiousness. However, others with a different variant may have fewer receptors, resulting in a milder response. Therefore, knowing your ADORA2A gene variant can be useful to tailor the amount of caffeine you should have in one go. I.e. go for a flat white with a single espresso over a double espresso!

How can your liver health play a role in your caffeine sensitivity?

Your liver is a vital organ involved in metabolising caffeine. If you have liver issues, such as liver disease or impaired liver function, it can impact your caffeine sensitivity. The liver produces enzymes, like CYP1A2, that break down caffeine into various byproducts. If your liver isn't functioning optimally, the breakdown process may be slower or incomplete, leading to higher caffeine levels in your system and increased sensitivity to its effects. Maintaining a healthy liver through a balanced diet, regular exercise, and not drinking too much alcohol can help you have a more positive experience of caffeine.

How does the total level of stress you are under in your life affect your tolerance of caffeine?

Stress levels can influence your tolerance to caffeine. When you're stressed (acute or chronic), your body produces cortisol, a hormone that regulates stress responses. High cortisol levels can make you more sensitive to the stimulating effects of caffeine, amplifying its impact on your nervous system. In these cases, even moderate amounts of caffeine may contribute to increased anxiety, restlessness, and disrupted sleep patterns. It's important to be mindful of your stress levels and find healthy ways to manage and reduce stress alongside your caffeine consumption.

Exhale Healthy Coffee - Caffeine Sensitivity Article Image 3

What does being habituated to caffeine mean?

Habituation refers to your body's ability to adapt to the effects of caffeine over time. When you consume caffeine regularly, your body builds a tolerance, resulting in a diminished response to its stimulating effects. Habituation is a decreased sensitivity to caffeine, caused by lowering the expression of the ADORA2A gene.

Should you try to improve your tolerance and ‘habituate to caffeine’?

Not necessarily. We have an awesome decaf which has similar levels of polyphenols and antioxidants as our regular coffee. It’s water-processed and so free from the nasty chemicals used to decaffeinate a lot of coffees. So you’re getting most of coffee’s wonderful benefits still. Most.

However, there are also a lot of science-backed benefits caffeine itself has in the body so some people looking for those specific effects may want to enjoy some amount of caffeine (even if in addition to decaf).

For more information, including 11 recent studies demonstrating various health benefits of caffeine read the ‘Is caffeine good for you?’ section of our article on ‘Coffee and Cholesterol’. It’s protective effects of the brain and liver being the biggest two.

Caffeine is also one of the most effective, if not the most effective, legal performance enhancers available. So for all levels of athlete ranging from your average 5km park-runner to bodybuilders or pro-cyclists and beyond, you may want to add caffeine into your training or your event day nutrition plan for that extra boost. Read more about how to use coffee and caffeine to improve performance and set a new PB in our article ‘Can coffee improve my PB?’.

Exhale Healthy Coffee - Caffeine Sensitivity Article Image 4

So, for those who want to add caffeine into their lives in a way that both respects and harnesses it’s power here are…

5 tips to improve your caffeine tolerance:

  1. Gradual Increase: Start with Small Steps

Slowly increase your caffeine intake over time. Begin with smaller amounts and gradually work your way up. This allows your body to adapt to caffeine's effects without overwhelming your system. Patience is key in building tolerance.

  1. Consistency is Key: Establish a Routine

Create a regular caffeine routine by drinking coffee at similar times each day. This helps your body develop a predictable response and maintain a balanced tolerance. Consistency allows your system to adjust more efficiently to the presence of caffeine.

  1. Moderation Matters: Find Your Sweet Spot

While habituation is possible, it's crucial to consume caffeine in moderation. Excessive amounts can still lead to adverse effects, irrespective of habituation. Pay attention to your overall caffeine intake (from all sources) and listen to your body's signals. Finding your optimal balance is essential for a positive caffeine experience.

  1. Personalise and Experiment: Know Your Genes

Everyone's body reacts differently to caffeine and a significant part of this is genetic. Experiment with different amounts to find what works best for you. Some people just genetically will always have a higher tolerance allowing them to enjoy its benefits without any negative effects.

  1. Mindful Consumption: Listen to Your Body

Practice mindful consumption by being attuned to your body's cues. Pay attention to how you feel after consuming caffeine and adjust accordingly. If you notice any anxiousness or other unwanted effects, consider reducing your intake. Perhaps try a half-caf where you mix our regular coffee and decaf for half the caffeine. Or try our organic, water-processed decaf.

Building caffeine tolerance is a gradual process that requires self-awareness and patience. It's essential to respect your body's limits to maintain a healthy relationship with caffeine. By implementing these tips, you can optimise your caffeine tolerance and enjoy the benefits while minimising any potential drawbacks.

Exhale Healthy Coffee - Caffeine Sensitivity Article Image 5

Disclaimer: As with any dietary or lifestyle changes, it's advisable to consult with a healthcare professional, particularly if you have any underlying health conditions or concerns.


Understanding your caffeine sensitivity is a key aspect of having a healthy relationship with coffee and will help you gain it’s health and performance benefits, without any negatives.

Your genetic makeup, liver health, stress levels, and habituation all play a role in how your body responds to caffeine.

As with everything in health, the key to optimising your overall well-being is to use the power of knowledge to make informed, personal choices and to tailor your caffeine intake to suit your individual needs!

If you're interested in learning more about 

So, breathe, sip, and savour each coffee moment, knowing that you're in tune with your body’s - unique caffeine journey.

Al x

Shop Exhale Decaf

1 comment



Thanks for this article its a succinct summary. As a cafeine-sensitive person I was curous about the habituation concept, but to be frank I think habituation is unimportant. The link to anxiety and stress mean my only concern on a daily basis is whether I should have zero caffeine, or a tiny bit. I’m generally low-stress and anxiety-free but pushing up my caffeine would invite these levels higher. Doesn’t seem worth it, I can just have a small amount of caffeine ad-hoc on ‘good days’ and keep my decaffeintated coffee as the ’habit ’. Love the exhale beans keep it up :-)

Leave a comment

All comments are moderated before being published.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Reading next

5 coffee myths you should stop believing
Coffee, the worlds most consumed fermented food!