Please ensure Javascript is enabled for purposes of website accessibility

Why Does Coffee Not Affect Me?

Rebecca Hanlon
Last Updated: February 28th, 2023

For most people, drinking coffee boosts their energy, helping them get through the day. However, there’s also a group of people who don’t feel any sort of caffeine kick after drinking.

If you’re part of the second group of people, you might ask yourself, “why does coffee not affect me?”.

Well, there are several reasons why coffee does not have the same effect on you as it does on other people. Let’s take a look at a few reasons why coffee might not have the energy-enhancing effects that it’s famous for!

It’s Hereditary

it’s hereditary

One of the most common reasons why coffee may not affect you is due to genetics. A 2011 study revealed that about 10% of people possess a gene that makes them immune to the effects of caffeine.

If you belong to the 10%, you may not have “sticky” adenosine receptors, causing caffeine to have difficulty binding to them. When caffeine can’t bind to these receptors, it won’t be able to block sleepiness and boost your energy.

Aside from adenosine receptors, liver enzymes also play a critical role. They dictate how fast your body breaks down caffeine and how long it stays in your system.

The primary liver enzyme responsible for caffeine metabolism is CYP1A2, and it has two variants. If you’re unfortunate, you might have the variant that metabolizes caffeine faster.

Faster caffeine metabolism means fewer effects of your morning cup of coffee on your body.

You’ve Developed Caffeine Tolerance

developed caffeine tolerance

Caffeine tolerance happens when you drink coffee too frequently. Once your body develops tolerance to caffeine, it manufactures more adenosine receptors since the existing receptors already have caffeine bound to them.

The effect? Nothing. You won’t feel the kick you need to stay awake or get through your day.

If you’re one of those who consume more caffeinated drinks than usual, you might observe that you can still sleep well even after drinking a cup. That’s caffeine tolerance right there.

To counteract this, try slowly limiting your caffeine intake. Over time, you can reset your body’s adenosine receptors and start experiencing the effects of caffeine once again.

You Lack Sleep

you lack sleep

If you don’t get enough sleep for one night, it doesn’t mean that caffeine won’t affect you.

But, don’t sleep for at least three nights and see what happens. You’ll be surprised to see that drinking a cup of coffee wouldn’t affect you like it normally would.

A possible explanation is that when you feel sleepy, your body produces adenosine. And, when you drink coffee, the caffeine binds to those particles, helping you stay awake.

When you lack sleep, adenosine reverses the effects. This can cause your cup of coffee to stop giving you that energy boost you’re used to.

Your Circadian Rhythm Might Be The Culprit

circadian rhythm might be culprit

When you feel an afternoon slump and sluggish, that’s your circadian rhythm doing its job. The circadian rhythm is your body’s internal clock that’s running on a 24-hour cycle. Your circadian rhythm dictates when to feel awake and sleepy.

Throughout the day, you will experience natural ups and downs in your energy levels, especially in the afternoon. And, you’ll feel your energy dip more if you always lack sleep.

But, even when you don’t lack sleep, you’ll still feel the natural dip because it’s part of your body’s wake-sleep cycle. So, when you drink coffee and notice that it’s not doing what it’s supposed to, that may just be due to a natural dip in your energy.

Because it’s natural, you can’t avoid it. But, you can do something to feel better. This includes taking regular naps and making sure you get a good night’s rest in the evening.

You’re Not Drinking Enough Caffeine

not drinking enough caffeine

Another reason you might not experience the standard effects of coffee is that you might not be consuming the right amount of caffeine. Like alcohol, the right amount of caffeine depends on your age, height, and weight.

For instance, if you’re tall, you might need to drink more coffee than normal so that the caffeine can help you stay awake.

It’s also best to check the amount of caffeine in the coffee you’re drinking. This is because different brands have different caffeine levels.

The Medications You’re Taking Might Be Getting in the Way

Medications might also affect how your body responds to caffeine.

Some can slow down how your body metabolizes caffeine. The following are possible medications that can slow down the breakdown of caffeine in your body, leading to fewer effects from your cup of coffee:

  • Heartburn medication
  • Antibiotics
  • Diabetes medication
  • Medication for hypertension
  • Antidepressants
  • Estrogens
  • Stroke medication

Why Does Coffee Not Affect Me? – FAQs

You may have other related questions about why coffee doesn’t affect your body the way it affects your friends.

Let’s dive into a few of these questions below.

Are There Benefits to Avoiding Caffeine?

While consuming just the right amount of caffeine doesn’t have as many negative effects as overconsuming, avoiding it might be healthier.

Avoiding caffeine can lead to less tension, better sleeping patterns, skin that ages slower, better nutrient absorption, and no teeth stains.

What Should You Do if Caffeine Does Not Affect You?

If caffeine doesn’t affect you because you have developed some kind of tolerance, the best thing to do is taper down your consumption.

And if you’ve gotten used to depending on it to stay awake, don’t stop right away. If you do, you’ll suffer side effects like headaches and jitters. Instead, try to taper it slowly.

Can Coffee Make You Tired?

Coffee itself will not make you tired, but its caffeine content does. There are three possible reasons for this:

  1. Caffeine in coffee blocks adenosine
  2. Coffee can make you urinate more because it’s a diuretic.
  3. The sugar you put in your coffee is causing your tiredness.

Everybody Responds Differently to Caffeine

Remember that everybody is different. Some people react to coffee while others don’t.

Factors including genetics, circadian rhythm, caffeine tolerance, lack of sleep, and not consuming enough can contribute to your body’s lessened caffeine effects.

Do you have another situation that’s not listed? Let us know in the comments if you also struggle with a lack of effects from caffeine!

Further Reading

About The Author

Rebecca Hanlon

Rebecca has been a blogger for over 5 years, before that enjoying a number of jobs to fund her passion for travel. She's taught English as a foreign language, a part-time Barista, a waitress, and a tour guide.

Just so you know, if you click on a product on and decide to buy it, we may earn a small commission.

Leave a Comment