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Why Coffee Doesn’t Wake Me Up?

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Why Coffee Doesn't Wake Me Up

Have you ever thought to yourself “Didn’t I just had a cup of coffee earlier? Why Coffee doesn’t wake me up? And, why am I sleepy again? Wake up!”? Well, you can encounter this on various occasions in life. Sometimes, you may experience tiredness in your eyes regardless of how many coffee cups you finished.

This is a modern problem where nearly everyone had the same problem going on in their working life. Coffee ineffectiveness could arise due to several reasons such as a high level of tolerance to coffee, dehydration, changing coffee brands, an excessive amount of sugar, too tired physically, or fast caffeine metabolism. Before diving deeper into those previously mentioned factors, this passage will give you a pleasant ride since the beginning of this problem.

Why Coffee Doesn't Wake Me Up? Introduction

We will descriptively elaborate what makes coffee so special in keeping us awake and conscious. Next, we will identify and discuss the possible root cause of coffee ineffectiveness. Finally, we will also provide solutions on how to deal with them as well.


How Does Coffee Keep Us Awake?

How Does Coffee Keep Us Awake?

Generally, coffee is made of a substance called caffeine. It is remarkably well-known in the world and, as a matter of fact, widely consumed globally. Caffeine is popular for its effectiveness to alert a person but also can bring harm if consumed improperly. Some research suggested that caffeine overdose can be detrimental as scientists experiment with insects. Scientists found out that if insects consume an excessive amount of caffeine it will make them dizzy and unable to function properly. Which happens in the case of insects that ate cacao leaves or seed. However, if caffeine is consumed in a lower or an appropriate amount, it will keep the insect to be reminded of that flower/target again. For example, caffeine can be also found moderately in pollen nectar, consequently, bees are able to return to that same flower for more pollen. 

The truth of caffeine

In the case of humans, caffeine keeps us awake and energized because caffeine blocks sleep-inducing molecules known as “Adenosine”. This molecule is constantly released once your brain supplies energy. Since our body is always striving for energy to perform tasks every day, our nervous system would release a substance called ATP to supply power for our body. Nevertheless, disengaging ATP will also disengage adenosine. And when adenosine enters the neuron receptors, it can create drowsiness or sleepiness. Therefore, this is the reason why the longer you work, you tend to feel tired, fatigued, and less-energized. 

Caffeine, on the other hand, acts as a stimulant for the nervous system. It replaced the neuron receptors from receiving adenosines (the sleep-inducing molecule) that make us want to go to bed. Hence, we tend to always feel energetic and positive when we consume an appropriate amount of coffee or caffeine generally. Since the structure of caffeine is similar to the molecular structure of adenosine, it can wedge into the adenosine receptors at all times. Although caffeine structure is not entirely fitting to the receptors, it is close enough to stimulate energy to wake the body. To summarize, adenosine inhibits the power and energy causing us to want to go to sleep. On the contrary, caffeine inhibits adenosine from working.

What make you feel sleepy?

Nonetheless, what actually happens that makes you feel sleepy even though you drank coffee? Scientifically speaking, over the course of time, your brain will get familiar with regular caffeine consumption. If your neuron receptors are constantly clogged with caffeine substances, your brain will gradually produce more neuron receptors. And that will allow the receptors to capture adenosine regardless. This could be the reason why you find yourself drinking more and more coffee as time goes on. 

Why Does It Not Wake Me Up? 

Normally, it is effective. However, like mentioned in the earlier paragraph, gradually your brain adapts to caffeine. Therefore, you need to drink more and more to wake yourself up. Apart from the scientific explanation, there are several factors that can cause immunity to caffeine or coffee in general. And some of the reasons could result from everyday life practices as well. Below are several reasons why caffeine is not working effectively as usual. 

Build-up Tolerance

Build-up Tolerance

You drank your coffee in the morning. And you still find yourself in exhaustion in the next few hours. And then you proceed to ask these questions “Why does not coffee keep me awake? Why do I still feel tired? I just had a cup of coffee a while ago?”. Well actually, when your body adapts to caffeine, your brain will think it is no longer a stimulator however just a regular liquid. Even though you just had a cup of cappuccino or even an espresso, it still would not work. You would still find yourself drooling and zoning off. Because your brain regards it as a norm now. Scientifically speaking, the neuron receptors now are multiplying more and more because they got used to the caffeine intake. 

The truth behide build-up tolerance

Furthermore, bear in mind, the build-up tolerance of caffeine does not originate from coffee alone but also from other drinks or food that contain caffeine in general. For instance, energy drinks may also contain caffeine. Chocolate is another alternative that is made of caffeine. According to the FDA, adults should be taking 400 milligrams of caffeine on average. That is approximately the amount of 4 cups of brewed coffee, 10 soda cans, or 2 energy shots. From now onward, you will have to pay close attention to what you consume not to overdose on caffeine intake. 


There is a solution to this problem. It is difficult sometimes because coffee is addicting, it is sweet, delicious, and aromatic. We understand that you just simply cannot get enough of it. But just like an intelligent man would say to himself: “Too much is never good for anything”. And this phrase also applies to coffee.

Firstly, to cut down your coffee intake. For instance, you can decrease your caffeine intake by going decaf. For those of you who are not familiar with the term decaf, it means coffee with 97% of the caffeine being removed. This is one of the alternatives to reduce caffeine inside your body.

Secondly, you can start dieting on caffeine. Go on a coffee break for half a month or so. It is understandable that this approach may seem very unbelievable and difficult for coffee lovers.

But cutting down on coffee allows your brain to relax. You might doubt yourselves at first. “What if my day is unproductive? And will this be capable of waking me up for real?” It definitely needs to take a little bit of time. There are definitely side effects from cutting down caffeine but what could be the worst-case scenario since you are not waking up anyway. 

Fast Caffeine Metabolizers

Fast Caffeine Metabolizers

Another factor that might cause the ineffectiveness is because you could be one of the people who is a fast caffeine metabolizer. People have different reactions to caffeine respectively. Others might experience the effectiveness and manage to stay alert throughout their work. On the other hand, high caffeine metabolism would hinder the effectiveness of coffee for certain individuals.

This could explain the reason behind why you have consuming coffee but it still has not to wake you up which often leads to consuming more and more coffee to stay awake. The probability to solve this matter is still limited as this is a matter of nature. And, it is also varied from person to person and there is no way on earth to combat the nature of the human body.

The truth behide fast caffeine metabolizers

However, there are other reasons why you might be immune to caffeine. For instance, you could be overweight, smoking, or using medication or contraceptives could also affect caffeine intake as well. If you have noticed that recently you have been exposed to one of the listed factors earlier, then the ineffectiveness could be from there. 

Excessive Sugar

Excessive Sugar

Sometimes after ordering an iced coffee with foam cream full sugar, do you notice that you are not fully awake? Or why does not that smell of coffee wake you up? Now that you drink it already, why is it that you are still sleepy and unproductive? Well, there is an explanation for it. 

It is probably because there is too much sugar inside your coffee. Thereby, instead of you drinking a cup full of coffee, you are sharing half or even more with sugar already. And adding so much sugar into a coffee can create a cycle of a sugar crash. This cycle is allowing your body to stay alert once you drink coffee because of the presence of sugar. One main function of sugar is to also provide energy and maintain consciousness for the human body. Nevertheless, sugar can also provide energy in a short period of time. This is often called the “sugar rush”. After the process of a sugar rush, which often lasted 2-4 hours, then you might feel an awkward feeling of tiredness and an urge of wanting to rest. Next, you will find yourself wanting more coffee. Then, you will feel energized because of the sweet coffee. Later, it will turn into a loop of a sugar crash. 

The truth behide excessive sugar

The excessive amount of sugar in your coffee can lead to this cycle and in the end, you would not be able to feel awake or alert at all. The solution to solve this problem is to cut down on sugar. According to the WHO, it is advised for all of us to limit at only 6 teaspoons per day added to our coffee or tea.  Bear in mind that if one consumes too much sugar, this could create disadvantages such as high blood pressure, diabetes, stroke, or heart failure. Therefore, cutting sugar down will create a healthy lifestyle as well as creating boosting the effectiveness of coffee intake. 


You can start gradually by cutting less and less sugar in your drink. By starting from 100% sweet to 70%, down to 50%, or less than that. Or you can simply follow the guidelines of WHO of maintaining under 6 teaspoons a day. Keep in mind, you must find the level that you are comfortable with so you can maintain both health and alertness. 



Dehydration could be one of the main problems why coffee is ineffective for you recently. The human body consists of 60% water. On the contrary, coffee has the tendency to drain the fluid from our bodies. The more coffee you drink, the more water you lose. This could be the reason why you are still feeling tired or why coffee is not waking you up as usual. Scientifically saying, water brings oxygen into the body. Whenever you drink water, one molecule of oxygen enters the body. And as we all know, oxygen supplies the heart. When there is sufficient supply of oxygen in the body, the heart could pump blood to reach every part of the human system. All in all, water provides oxygen for the heart to pump blood and produce energy. 

The truth behide dehydration

However, dehydration can cause when you drink too much coffee at a fast pace or at a high concentration. As aforementioned, coffee can cause water loss in the body because it contains a substance called a diuretic. And this substance will enhance urine production as caffeine stimulates blood flow in the kidneys. So, you might find yourself going in and out of the toilet frequently. 


The solution to this problem is to keep a close watch on your coffee consumption. It is best to limit yourself from drinking too much coffee or consumption of caffeine in general. And most importantly to drink water to supply enough oxygen for the heart to produce blood. 

Too Tired/ Fatigue

Too Tired/ Fatigue

When the human body is already tired or exhausted, it needs to rest. In that case, caffeine cannot fix it. This usually happens with someone who stays up all night. And Adenosine already settled in the receptors. Therefore, even with coffee, you are unable to wake up. Because you need sleep. 


The solution to this is fairly simple. Sleep is the ultimate solution. Once your body has the sleep or rest that it needs, you will be able to feel awake again. Even without drinking coffee, you will be energized after a good sleep. 

Change of Coffee 

As we all know that there are many coffee brands out there. However, these brands have a different formula when it comes to coffee making. One might prioritize creaminess whereas others are trying to preserve the best aroma of coffee. Correspondingly, this could be the reason why your new coffee is not working. Because your last coffee was stronger than the recent one.


To solve this problem, there are two ways. Firstly, you might have to return to the one old that you are used to drinking. It is more effective. Or if you like the texture or the taste of the new one better then please experiment with it. Probably, it will take a little bit of time to have your body familiar with it. Secondly, you can also find a different brand that prioritizes caffeine or has higher caffeine. This way, you will be able to get the coffee that you want and effectively wakes you up for the day. 


Coffee is considerably a gift for mankind. It has the blessing texture, taste, and aroma that got you addicted. Moreover, it is a gift that helps mankind to stand against demanding deadlines and late-night work. Without coffee, probably the world would be chaotic. But it is even more chaotic when you have the coffee in your hands but it is not doing its job to wake you up at all. You are still sleeping and feeling tired after several cups of coffee. Well, in the previously mentioned paragraphs, we have already established a variety of causes why coffee does not wake you up.

Possibly, it could result from your genetics which makes you immune to caffeine. It could be from over-drinking coffee, dehydration, or possibly from changing coffee brands. Since you are fully informed about these root causes, we hope that our solution could be life-changing for you as well. 

How does caffeine keep us awake? – Hanan Qasim By TED-Ed