Popular keywords

Sleep calculator

Discover how much sleep you really need

Why Does Coffee Make Me Sleepy? – Know the Reasons

Fact Checked
Up to date
Update: June 30, 2023
6 min read

Written by

Manya Mishra
Content Writer
Illustration Of Why Does Coffee Make Me Sleepy

For most of us, coffee is our weapon of choice that helps us wake up and ensures we are ready to face the long day ahead. While for some, one hot cuppa suffices, some need more. From instant to filter coffee, there is a variety available in the market today. But the popular ingredient here is caffeine. 

Now, when you consume caffeine, it increases brain activity and stimulates the nervous system. This is why when you ingest caffeine in small amounts, it leaves you refreshed. However, there are chances when instead of making you feel awake, caffeine leaves you feeling sleepy. So, if you are wondering why does coffee make me sleepy? Well, we have all the answers for you ahead. 

Reasons Why Coffee Makes You Sleepy

Does coffee keep you awake? Yes, it is supposed to. But some of the reasons why coffee makes you sleepy include; 

It Is Diuretic 

So, can coffee make you tired? Coffee is a diuretic, which means when you consume excessive amounts, you feel like urinating frequently. But this is only when you consume more than 5 cups or about 500 mg daily. So, if you are someone who drinks too much coffee every day, there are chances that you are losing fluids and feeling dehydrated, which is making you feel tired. 

If you feel sleepy because of the dehydration effects of coffee, you may also experience other symptoms, such as dry mouth, thirst, dry skin, and dizziness. Therefore, drinking plenty of fluids and consuming fruits and vegetables is essential. However, if you feel faint, confused, or if there is rapid breathing, make sure you visit your healthcare provider immediately. 

It Blocks Adenosine Receptors 

If you are wondering, why does caffeine make me tired? Then this might be the reason. The caffeine gets absorbed by your small intestine and your stomach when you drink coffee. It then enters your bloodstream and reaches various organs, including your brain. Here, it tends to block the adenosine receptors.

Adenosine is a chemical that regulates the internal clock which increases when you awake and decreases when you sleep. So, when the adenosine receptors are blocked by caffeine, it slows down the brain’s activity. It makes you feel tired because of coffee dehydration.

Maybe It Is Sugar Crash 

If you favour flavoured coffee or enjoy your cup of joe with high amounts of sugar, it can lead to a caffeine crash because of the sugar rush! When you consume too much sugar, your body produces the required amount of insulin. But this also causes the blood sugar levels to take a hit. And your blood sugar is what supplies you with the required amount of energy.

You start feeling tired and sleepy when your blood sugar levels go down. This may also make you irritable, sweaty and anxious. So, if you are thinking, why does coffee make me sleepy, this can be why. 

It Can Be Because of Mould 

According to a 2003 NIH study, there are chances that your coffee has mould. 60 samples of the raw coffee beans, also known as green coffee from Brazil, were examined. Almost 91.7% were contaminated with mould. Mycotoxins were also found, which is a product of microfungi. And exposure to mycotoxins can lead to chronic fatigue. This can make you feel tired even after a good night’s sleep or rest. Some of the other symptoms of mycotoxin exposure include difficulty in concentrating and dizziness. So, if you were thinking about why coffee makes me tired, this can be the reason.

You May Be Experiencing Withdrawal Symptoms 

If you are someone who has quit drinking coffee recently because you think caffeine makes me sleepy. But despite that you still feel tired and sleepy, this can be a withdrawal symptom. Now, you know what coffee does to you. It keeps you awake and refreshed. 

So, if you were someone who drank more than 4-5 cups of coffee every day, immediately quitting can lead to sleepiness, nausea after coffee, irritability, and headaches. Therefore, if you are someone who wants to leave drinking coffee, do it gradually. Cut back on ½ a glass for 2-3 days and move ahead.

You Have A High Tolerance 

As someone who drinks too much coffee and feels like coffee doesn’t work, it can be because you have a high tolerance. If caffeine doesn’t affect me, is what you think, this can be because you drink excessive amounts of coffee daily. Tolerance builds because you start getting addicted to coffee. The more you drink, the more focused and alert you feel. So, this builds a dependency on coffee. So, you may be someone who thinks coffee helps me sleep, rather than keeping you awake. Therefore, always consume less than 500 mg of caffeine. 

It Is Associated With Stress

Caffeine and insomnia and stress are interconnected. When you are too stressed, it can keep you awake due to stress-induced insomnia. This can keep you tired and unable to sleep. The science behind it is that when the stress hormone known as cortisol makes its presence felt, our body releases stress as a response. And here, as a response, you are unable to fall asleep. And when you consume caffeine, it releases more epinephrine and cortisol. If you have ever wondered why coffee makes me anxious, this can be the reason.

Other Side-Effects Of Coffee On Your Body

While a cup of coffee can be great for some much-needed energy, too much caffeine can lead to side effects, such as;

Digestive Problems 

Drinking coffee first thing in the morning can help your bowels move quickly. This is because of the laxative effect coffee offers. But, large doses of coffee can lead to loose stools and even diarrhoea. In one study it was found that caffeinated beverages may aggravate gastroesophageal reflux disease (GERD) in some.

High Blood Pressure 

Coffee produces a stimulatory effect, which can increase blood pressure. And high blood pressure can put you at risk of heart attack and stroke. 


Caffeinated beverages can elevate your energy levels, but can also leave you tired. If you are one of those people who think coffee makes me tired, this can be why. In one study, it was seen that caffeinated drinks increased alertness and energy levels tremendously. However, the next day its participants were more fatigued than usual. 

Heart Beats Faster 

Due to the stimulatory effects of caffeine, drinking coffee can lead to a rapid heartbeat. It can also lead to atrial fibrillation, which is a condition in which the heartbeat rhythm gets altered. 

How Can You Minimise Side Effects of Coffee

In order to prevent the negative effects associated with coffee, you can try the below tips. 

  • Make sure you limit your coffee intake. You must not drink more than 2-4 cups or more than 400 mg of coffee per day. 
  • Make sure you stay away from beverages that have high sugar content. This will prevent sugar crashes and keep your glucose levels steady. 
  • Avoid coffee before bed. Caffeine and sleep don’t really go hand in hand. This will disrupt your sleep and leave you feeling tired at night. Hence, don’t drink coffee at night. 
  • Consume a lot of water before and after you drink coffee to avoid any dehydration. 
  • Don’t drink coffee post 12 or 1 PM as coffee remains in the system for at least 10 hours. Hence, it will make it difficult for you to fall asleep at night. 
  • Choose quality coffee from well-sourced beans to avoid the possibility of mould. 

Caffeine Limits to Be Considered

If you want to enjoy the positive effects of coffee, it is important to consume less than 400 mg of caffeine. It’s always better to consume only 1-2 cups every day before the afternoon. This will keep you going throughout the day and ensure you are able to fall asleep without any interference.


So, if you were thinking coffee makes me tired, you have all the answers with you. Make sure you limit your caffeine intake and drink plenty of water to experience only the positive effects of coffee. Otherwise, it can leave you feeling sleepy rather than energetic. 


Can I have a coffee before bed?

No, you must not consume coffee before bed as coffee is a stimulant. And this can hamper your sleep quality. 

How long does it take for caffeine to kick in?

If you are someone who thinks coffee doesn’t wake me up, then give it a few minutes. You will be able to see the effects of caffeine after 15 minutes.

How long does coffee last when you drink it?

Coffee remains in your system for at least 10 hours. And if you drink too much coffee, you may feel tired after drinking coffee and it can also make you feel sleepy after coffee.

Is it bad to drink coffee at night?

If you are someone who has a night shift and wants to stay awake, coffee in limited quantities can be beneficial. However, drinking too much coffee can make you feel like coffee doesn’t work for you. But if you are planning to sleep, you must avoid coffee.

Can coffee affect everyone?

Coffee doesn’t affect everyone in the same way. For instance, some people just need one cup of coffee to feel a burst of energy throughout the day while others need 2-3 cups. And for some coffee helps them sleep

What drinks help you stay awake?

All caffeinated drinks can help you stay awake. You can also try soda, caffeinated tea, coffee, and caffeinated chocolate products.


people like this article


Written by

Manya Mishra
Content Writer
Bachelor's Degree in English Literature 7 years of experience as a content writer Has experience writing for various industries, including health and wellness, travel, and technology

Read More About Food and Sleep
Banana Before Bed
Update: June 22, 2023

  • 6 min read

Protein Shake Before Bed
Update: May 25, 2023

  • 7 min read

7 Ways To Avoid Feeling Sleepy After Lunch
Update: May 12, 2023

  • 3 min read

Drinking Water Before Bed
Update: May 11, 2023

  • 5 min read

Eating Before Sleeping
Update: May 11, 2023

  • 7 min read

Alcohol And Sleep
Update: June 7, 2023

  • 5 min read