Why Caffeine Doesn’t Affect You + How to Fix It

caffeinated drinks

Caffeine has proven to be an exceptional boost when consumed in appropriate amounts, remarkably improving energy levels, mood, and productivity. However, what if caffeine doesn't work for you? What could be the cause and what are the potential remedies?

A caffeine insensitivity can result from the behavioral factor of drinking caffeine too often and developing a tolerance to it, or from genetic factors such as having lots of adenosine receptors in the brain and a fast rate of caffeine metabolism in the liver.

If you’re someone who doesn’t feel the effects of caffeine and wants to know why, this article is for you! Below I’ll give you a few explanations of why caffeine doesn’t affect you, and then go over some of the things you can do to fix it. Let’s get started!

What is Caffeine?

Caffeine is a natural stimulant that affects your nervous system, helping you stay alert and awake. The drug does this by attaching to adenosine receptors in your brain, blocking adenosine, a chemical that makes you tired and drowsy, from attaching to the receptors.

Caffeine also releases “feel good” chemicals in the brain and raises adrenaline levels in the bloodstream.

Why Caffeine Doesn't Affect You


You Have Developed a Caffeine Tolerance

The first and most obvious possible explanation for why caffeine doesn’t affect you is that you’ve developed a tolerance to it.

If you regularly drink coffee, energy drinks, or even soda or green tea, your body may have developed a tolerance to caffeine, and won’t feel the effects of it at the same doses as it used to.

As I talked about above, caffeine affects your body by blocking adenosine, a chemical that makes you feel drowsy and tired, from attaching to its receptors in the brain. Well if you’re drinking caffeine often, your body begins to adjust and compensate for the blocked adenosine receptors by creating more of them.

This means that someone that has a caffeine tolerance simply has more adenosine receptors in their brain, which means more caffeine is needed to block them and prevent drowsiness. Caffeine becomes more of a way to get back to their old “normal” rather than the boost of energy they used to get from it.

If you drink caffeine regularly, don’t really feel its effects anymore, and feel tired or fatigued without it, you may have developed a tolerance to it.

How to Fix a Caffeine Tolerance

The best way to fix a caffeine tolerance is to reset it. Resetting your caffeine tolerance means abstaining from caffeine for a set period of time to allow your body to get back to its old normal.

You can do this in 2 different ways:

  1. Slowly reduce the caffeine you drink each day until you’ve completely cut it out

  2. By going cold turkey and completely cutting out the caffeine in your diet immediately

The time it takes for your body and its adenosine receptors to reset will vary based on how much caffeine you were drinking, but you should only need 2 weeks off of caffeine at most to get things back to normal.

Unfortunately, if you’ve been really reliant on caffeine for your energy you could experience withdrawal symptoms like headaches and an inability to focus, but these will get better with every consecutive day you spend uncaffeinated.

Once you start drinking caffeine again after a week or two off, it should have its strength and energy-boosting effects back, feeling like the first time you drank it again.

If you don’t think you've developed caffeine tolerance from drinking caffeine too often, or have taken time away from it and still don’t feel its effects, it's probably because of your genetics. And there are two areas of your body that could be contributing to a genetic intolerance of caffeine, the number of adenosine receptors in your brain and the speed of metabolism in your liver.

Genetic Factors that Can Lead to a Caffeine Intolerance

The Amount of Adenosine Receptors in the Brain

As I talked about earlier, you feel the energy boosting effects of caffeine when the molecule binds to and blocks adenosine receptors in your brain.

Just like caffeine tolerance can be developed by your brain creating more adenosine receptors, some people are born with or develop extra adenosine receptors over the course of their life, even if they don’t drink caffeine.

If you are one of these people with lots of adenosine receptors, your body has a genetic or “natural” caffeine tolerance, which means it’ll take a lot more of it to get you buzzin.

The Speed of Caffeine Metabolism in Liver

While extra adenosine receptors in the brain can be a genetic factor that leads to someone not feeling the effects of caffeine, the more common genetic explanation for not feeling the effects of caffeine is the speed of caffeine metabolism in the liver.

Caffeine metabolism is basically your body processing the caffeine you've drank and using it for energy. And everyone's body processes caffeine at a different speed.

If you are a slow caffeine metabolizer, you can drink a cup of coffee and feel the effects for hours while your body slowly processes it. But if you’re a fast caffeine metabolizer, which you might be if you’re reading this article, your body processes caffeine so efficiently and quickly that you never get a chance to feel its effects, even after drinking a lot of it.

The mechanism behind this process is an enzyme called CYP1A2. This enzyme does the metabolizing and is created by the CYP1A2 gene. So if you are born with a CYP1A2 gene that produces a lot of the enzyme, you will metabolize caffeine faster and not feel its effects as much as other people (theladders.com).

Apparently, about 10% of the population are rapid caffeine metabolizers and thus not very caffeine sensitive (AKA hyposensitive) (Caffeineinformer.com). Hyposensitive caffeine drinkers can drink more than 500mg of caffeine without feeling much of an effect.

So What Can You Do About a Caffeine Insensitivity?

If you’re someone who is hyposensitive to caffeine and doesn’t feel its effects but wishes you did, here are some behavioral and environmental factors that you can change to alter the speed of your caffeine metabolism.

How to Change the Speed of Your Caffeine Metabolism

Change What You Eat

Research has found that smoking can double the speed of your caffeine metabolism! This may explain why smokers drink so much coffee: because in order to feel its effects their body needs double the amount of caffeine as it normally would.

Your diet can also affect how fast you’re metabolizing caffeine. Some research has found that grapefruit juice consumption decreases caffeine metabolism by 23% and prolongs its half-life (how long it stays in the body until half of it is gone) by 31%

Vegetables like broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, kale, and turnips also increase the metabolism of caffeine.

Alcohol intake of 50g per day (5 drinks) prolongs caffeine half-life by 72% and decreases caffeine metabolism by 36% (coffeeandhealth.org).

Certain medications can also influence how your body processes caffeine. So if you’re not feeling its effects and are taking some type of medicine regularly, you may want to consult your doctor to see if what you're taking slows the rate of caffeine metabolism.

Change What You Drink

Another adjustment you can make to try and feel the effects of caffeine better is to change what you’re drinking.

If you’re a coffee drinker and a regular cup of joe isn’t doing the trick, try an Americano. It’s a double shot of espresso in hot water and has more caffeine than a regular coffee, while still tasting pretty similar.

Or, if you still want to drink normal coffee, check what kind of coffee beans you’re using. Robusta coffee beans, while not as popular as arabica, have twice the amount of caffeine.

And if you’re a tea drinker, black has much more caffeine than green, white or oolong.

There's also a really cool company called Zest Tea that makes tea bags with 150mg of caffeine in them. They'll not only give you tons of energy but also taste pretty good. If you’d like to try it out, you can find Zest on Amazon here.

Final Thoughts

Whether genetics or caffeine tolerance are causing you to not feel the effects of the drug, there are some things you can do to increase your caffeine sensitivity.

Just remember that the recommended daily amount of caffeine is only 400mg. This is for regular caffeine metabolizers, so if you're a fast metabolizer you can probably get away with more, just don’t go too crazy since we still don’t know much about how excess caffeine intake can affect the body.

I hope this article could help you out! If you’d like to learn more about caffeine and coffee, be sure to check out the rest of my website!


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