Caffeine doesn’t affect me! Why?

Sabina Muminović Last updated: 27 October 2023

Millions of people start their day the same way – with a steaming cup of aromatic coffee. But for some, caffeine simply doesn’t do the trick. Discover the answers to your question “why doesn’t caffeine affect me?”


Every day people around the world drink around two billion cups, coffee culture is booming, but some people just don’t get the hype. There is no caffeine-induced surge of energy – or even worse, coffee only makes them jittery and unwell.

High and low caffeine sensitivity and why it might not have the desired effect depends on many factors. One of them is your genes! 

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In this blog, you’ll discover the most likely reasons, as well as tasty and healthy alternatives to coffee, and how to stay energised without caffeine.

Why caffeine doesn’t work on you

Are you trying to find the answer to “why caffeine doesn’t affect me”? There are several factors that determine how caffeine works its magic on you. Let’s take a look:

You are too used to it. Your first cup of coffee probably packed a punch and made you feel like you could be jumping from buildings. But after a while, you needed another for the same effect, and maybe even a third … in simple words, your body got used to it!

Our body develops caffeine tolerance fairly quickly. If you think it might not affect you anymore because you drink too much and too regularly, try cutting back.

On weekends, when you’re not working, or on holidays, replace coffee with herbal tea or freshly squeezed fruit juice. If you like the taste of coffee, choose decaffeinated coffee – it has the same aroma and flavour – or a coffee substitute (read on for ideas!).

After a while, your body will regain its caffeine sensitivity, and you will feel its rush again!

Your lifestyle and medical conditions. Infants and pregnant women have slower metabolism of caffeine, so do females during the luteal phase of their menstrual cycle, and patients with liver disease. On the other hand, cigarette smoking almost doubles the rate of caffeine metabolism.

You are taking medications or supplements. Certain prescription medications and supplements can interact with caffeine, contributing to how it affects you. Consult your doctor if you take antibiotics, antidepressants, bronchodilators, or antipsychotics. Also, be careful if you regularly consume any of the following herbs or supplements: calcium, echinacea, melatonin, magnesium, or red clover.

Your genes. If even a small amount makes you restless, jittery and feeling unwell, you might not tolerate caffeine well. And that has a genetic component. Let’s take a closer look at the genetic background of caffeine metabolism.

Caffeine and genes

Caffeine is metabolised in our liver by the enzyme CYP1A2. This enzyme is responsible for up to 95 per cent of the entire caffeine metabolism. Consequently, the variation in the gene responsible for its synthesis has an important influence on your caffeine metabolism.

If you have an unfavourable genetic variant of the CYP1A2 gene, your body produces less of the enzyme, and you metabolise caffeine slower. As a result, coffee (and other caffeinated drinks) have a stronger effect on you.

As positive as it might sound, people with such genome can have higher blood pressure as a result of drinking coffee, making them more susceptible to medical conditions related to increased blood pressure.

Favourable variants of the CYP1A2 gene are linked with rapid caffeine metabolism. That means that caffeine is quickly removed from your body. Around 52 per cent of people have such a genetic makeup, and it makes them less susceptible to the risk of health complications related to increased blood pressure. It also means that caffeine likely doesn’t affect them as expected – its effects don’t last as long as they do in slow metabolisers.

But carrying unfavourable variants doesn’t mean you need to quit your favourite morning routine. It just warns you that too much caffeine can be harmful to you, and you should adjust your intake. You can discover exactly how much caffeine is recommended for you with personalised recommendations you receive with our DNA test.

A man and a woman laughing while drinking coffee in a coffee bar

Energised without caffeine

Don’t let the fact “caffeine doesn’t affect me” stop you! There are other ways to charge your batteries.

Here are the top tips to help you remain focused and productive all day long!

Exercise. A quick morning workout, a nice stretch, a walk after you’ve eaten will get your blood flowing, improve concentration, and provide other benefits for your overall health.

No phone before bed. Using your smartphone, tablet, or e-reader disrupts your sleep. Research shows that using light-emitting electronics before bed can take you longer to fall asleep, lower your melatonin (a hormone that promotes sleep), and makes you less alert the next morning.

Ensure quality sleep. Sleep with the blinds open. Your body is attuned to the cycles of the natural world. Research shows that exposure to gradually increasing illuminance – a sunrise – helps your body recognise that it is time to wake up and start the day.

Boost your brain with herbs and aromatherapy. If you can’t count on caffeine, try alternatives that are praised for increasing your cognitive functions. Ginkgo biloba, ginseng, rosemary essential oil, cinnamon, and mint can all stimulate your cognitive performance and alertness.

Stay hydrated. When was the last time you drank a glass of water? When you feel thirsty, your body is already low on hydration. Mild dehydration can have many negative effects on our body, including disrupting our concentration, so always keep a water bottle on hand and take regular sips throughout the day.

Eat well. Food is fuel, but just as there are several types of fuel for your car, there are different foods with a different effect on you. Focus on nutritious food which gives longer-lasting energy. Think lots of fibre (leafy greens, whole-grains, legumes), fruits, and vegetables. Too much simple or processed carbs (bread, pasta, pastries) is not only unhealthy but will make you feel sluggish after a meal.

Let the fresh air in. Stall and warm air in your office or your home can make you sleepy and lethargic. Open the windows for a couple of minutes or turn down the air conditioning to get more oxygen and awaken our brains. If you have a chance, take a cold shower.

Get some sun. Vitamin D, also called the sunshine vitamin, is a micronutrient we get from exposure to sunlight. Scientists have discovered that the lack of this vitamin can result in fatigue, and you can be genetically predisposed to lower levels.

Sing out loud. Feeling down and low on energy? Belt out your favourite song! Studies show that singing increases energy and lowers tiredness. If you prefer not to reveal your singing talents to the entire office, tapping to the rhythm has the same effect.

Take a nap. After lunch, take a 20 to 40-minute nap. That is the optimal time in which you’ll feel restored but won’t doze off so deeply that you would wake up wondering what day of the week it is.

Laugh out loud! Saw a hilarious meme while you were browsing the net during lunch? Stumbled across a funny video? Don’t hold back – laugh until your belly hurts and you are wiping tears from your eyes. You will feel instantly alert because a good laugh is like a good stretch – it improves blood circulation, elevates heart rate and blood pressure, and quickens your breathing.

The best coffee substitutes

So if you find out that caffeine is not your best friend, don’t worry; there are excellent replacements for your favourite drink. Coffee substitutes mimic its look and flavour, but contain little or no caffeine. And best of all, they have their own health benefits!

  • Chicory drink is the most popular, because its taste is very similar to regular coffee. It also aids in digestion and is rich in inulin, insoluble fibre which promotes healthy bacteria in your gut.
  • Golden milk is a spicy oriental mix of ginger, cinnamon, turmeric, black pepper and optionally cardamom and vanilla. Curcumin from turmeric is a potent anti-inflammatory substance.
  • Acorn coffee is for those who like discovering new tastes. It has natural sweetness combined with bitterness that we associate with coffee, rounded by an earthy taste. And the best? No caffeine!
  • Tea is for those who want a more gradual approach to cutting down on caffeine. A cup of black or green tea contains about half of the caffeine found in a cup of coffee, but studies show that it might still have a sufficiently stimulating effect. It is also a strong antioxidant.

If you are an avid coffee lover, don’t quit suddenly. Your body is used to caffeine, and you might experience “withdrawal” symptoms, usually in the form of a headache. Reduce your caffeine intake gradually.

Now that you’re familiar with the possible reasons coffee doesn’t work on you, let’s take a closer look at the beverage millions of people around the globe rely on to get them through the day.

Caffeine content in the most common drinks

Caffeine content in your drink depends on several factors, including coffee variety, method of brewing, beverage brand, serving size, etc. Even though caffeine content might vary, the picture below gives you a good overview of average caffeine content in common beverages and food.

Visual representation how much caffeine is in food and drinks

If you want to expand your knowledge about coffee and caffeine in general, read on to discover what caffeine does in your body, its positive and potentially negative effects, and who should avoid caffeine.

Interesting facts about caffeine

Do you think that the world’s biggest consumers of coffee are Colombians, Brazilians, or maybe Italians?

Then you’ll be surprised to learn that the top three places with the highest consumption of coffee are Nordic countries: Finland, Sweden, and Iceland. An average Finn drinks 12 kg of coffee annually!

This wildly popular drink owes its energising effect to a substance called caffeine.

How does caffeine work?

Caffeine is a stimulant, making you more alert and awake by speeding the transport of messages between your body and your brain. Chemically, it is an alkaloid found in seeds, nuts, and leaves of different plants, found mostly in South America and East Asia.

Caffeine is very quickly absorbed into your bloodstream and you start feeling its effects within minutes of drinking it. They last until your body fully metabolises them. Although the response to caffeine is highly individual, in general, it affects you up to 6 hours, with a peak effect 15 to 45 minutes after drinking your coffee.

If you have a high caffeine sensitivity, you might feel its effects even until the next day.

Where do we find caffeine?

When we say caffeine, we think of coffee, which is indeed the most common source of caffeine. Coffee is a drink made of ground coffee beans, which grow on a bushy plant called Coffea arabica.

Caffeine is pretty abundant in nature. You probably know that green or black tea has a similar effect to coffee. Brewed tea and mate leaves are a popular alternative to coffee, as are powdered guarana seeds.

Caffeine is also found in kola nuts and even in cocoa beans. Kola nuts are used for flavouring drinks and have given a name to colas, caffeinated and carbonated beverages (the most popular are Coca-Cola and Pepsi).

Cocoa beans are the main ingredient of chocolate. So that bar of chocolate you just ate can also give you an energy boost! Be sure to choose dark chocolate with higher cocoa content and less sugar. While sugar is a great energy source, it can also have other, less desirable effects.

Caffeine is also found in energy drinks, and its content varies according to brands, so make sure you read the labels. Avoid mixing energy drinks with alcohol as it might strengthen its effects.

Is caffeine dangerous?

In general, caffeine is not dangerous. Up to four cups of coffee – which contain around 400 mg of caffeine – is a safe amount for most healthy adults.

Who should avoid caffeine?

Pregnant women and breastfeeding mothers should drink no more than 200 mg of caffeine daily. Especially if you want to get pregnant, replace coffee with other drinks, as caffeine might affect fertility.

Caffeine is not recommended for children, and adolescents need to be careful with their consumption because they have a higher caffeine sensitivity. Because of its acidic nature, caffeine might irritate your stomach and even cause heartburn.

The pros and cons of caffeine

Not only does caffeine wake you up and make you a functioning member of society, scientific research also shows some promising health benefits. Let’s take a look at why regular coffee drinkers might benefit from their habit, and what can happen if you indulge in too much caffeine:

Pros and cons of caffeine

Discover, improve, live better

Caffeine is a must for millions of people. But even if you can’t enjoy its benefits, there’s still a lot you can do!

Discovering your genetic predispositions and following personalised recommendations about caffeine intake will help you enjoy coffee without consequences or find healthy alternatives to help you stay in control of your day.

Take the MyLifestyle DNA test to discover your caffeine metabolism and a myriad of other useful facts about the functioning of your body!



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