Why Coffee Doesn’t Wake Me Up Anymore? (All Questions Answered)

Some people advocate that they don’t have any reaction to caffeine. To many coffee lovers, this may sound strange, if not even impossible.

This phenomenon, which is annoying for some individuals and a blessing for others, has been reviewed by many researchers. Lack of sleep, genetics, and too much or even too little caffeine are only some of the causes of your incompatibility with coffee.

If you are curious to learn more, then we recommend you read this thoroughly.

What Happens When You Drink Coffee?

It only takes a sip of good coffee for a smile to appear on their faces for many people. However, more serious things happen inside our body when we introduce coffee and, consequently, caffeine. This substance undertakes a long trip through our bloodstream, and it reaches all areas of our body within a few hours until it exits through our urine.

Before we follow caffeine in its journey inside our body, we should underline that this substance is not just contained in your daily mug of Americano. Several energy drinks, beverages, and even medications may contain caffeine, which you might already be ingesting every day without even realizing it.

The Beginning of Caffeine’s Journey in Our Body

Caffeine enters our bloodstream through the stomach and intestines and circulates our body. During its long journey, it joins up several receptors, the majority of which is in the brain. 

Among these receptors, there is the adenosine. However, as each person is different, caffeine might not be able toproperly  bond with your adenosine. If your adenosine receptors don’t join up with caffeine, then no matter how many cups of Americano you drink: coffee will never wake you up properly.

How Our Body Metabolize Caffeine

However, caffeine’s journey inside our body doesn’t end when it reaches our brain to meet with our adenosine. In fact, it travels to our liver, when it’s finally metabolized by a cocktail of enzymes, such as the CYP1A2 enzymes. At this point, genetics comes into play once again. If your body naturally produces less of these enzymes, then caffeine will be knocked out quickly. Contrarily, if you are a slow caffeine metabolizer, one single espresso may keep you awake for many hours.

How Does Coffee Affect Your Body?

The caffeine in your daily cup of espresso does much more than just keep you awake and give you a boost of energy. Caffeine is a particular substance which can affect our body in numerous ways. 

Some of the consequences of caffeine consumption on our body may look scary. However, it must be noted that these happen only in extreme cases, for example, if you consume several cups of coffee or energy drinks every day. It is rare for the average individual to experience very bad effects of caffeine ingestion. In other words, you can keep drinking your daily cuppa without worrying too much. If you still believe that coffee and caffeine affect your health, you should consult your doctor, especially if you have any preexisting condition. Drinking coffee is a pleasure that should never become a danger for our body.

Central Nervous System

Caffeine is a stimulating substance that has the power to enhance the alertness of our central nervous system. For this reason, caffeine is a common ingredient in medication used to treat migraines, headaches and drowsiness. Besides, caffeine can relieve the symptoms of a hangover. On the other hand, drinking too much caffeine or even withdrawing from it can cause headaches. 

Under certain circumstances, individuals may experience caffeine overdose. Some of the symptoms are hallucinations, confusion, and vomiting.

If your body is too used to caffeine, you can also experience anxiety, drowsiness, and irritability.

Heart Rate

Ingesting too much caffeine can cause a rapid heart rate, which can be a concern for those who have a preexisting heart issue. If you are worried about your heart rate, you should limit your consumption of caffeine, as well as of other stimulating substances.

Digestive and Excretory System

The acidity of caffeinated beverages can cause heartburn, nausea, and vomiting.

Drinking too much caffeine will upset your stomach. Besides, your body cannot store any extra caffeine, which will then be processed in the liver and got rid of through your urine. This is one of the reasons why many individuals experience an increase in urination when they drink too much coffee.

If you suffer from preexisting stomach issues, such as acid reflux or ulcers, you should discuss with your doctors whether you can have caffeine.

Muscular System

Large amounts of caffeine might interfere with the absorption of calcium, leading to bone thinning conditions like osteoporosis. If you ingest too much caffeine or if you are suddenly stopping its consumption, you may also experience achy muscles.

Circulatory and Respiratory Systems

Caffeine is absorbed from your stomach and then reaches the highest levels in your bloodstream within a couple of hours. This means that caffeine can make your blood pressure increase for a short time, leading to a significant release of adrenaline. 

These effects should disappear within a few hours, but individuals with irregular heart rhythms should make sure this doesn’t interfere with their condition. For example, those who have high blood pressure or suffer from hypertension or other heart-related problems should consult their doctors to check whether they can consume caffeine safely.

Reproductive System

Since caffeine travels within the bloodstream, it will eventually enter your reproductive system. Women who consume too much caffeine might experience difficulties in getting pregnant. 

If you are already expecting a baby, you should be aware that caffeine crosses into the placenta, too. Its stimulating effects will cause your baby’s heart rate to increase. Humongous doses of caffeine can cause slowed fetal growth and even increase the risk of miscarriage.

Does Cold Brew Have More Caffeine Than Standard Coffee?

We all need our coffee to get us going in the morning. Since this is one of the first things we introduce in our bodies every day, we should make our coffee break a pure pleasure and follow our taste. For example, some may prefer a sip of bitter espresso, while others would never say no to a delicious cold brew. At this point, you might be wondering which one, between cold brew and other coffee-based beverages, has the biggest caffeine punch. Don’t worry, we have all the answers you are looking for.


It is a common belief that espresso has more caffeine than any other type of coffee, although this isn’t true. An average shot of espresso contains from 64 to 75 mg of caffeine, which is approximately what you can get by drinking any other single cup of coffee.

Drip Coffee

Drip coffee varies in caffeine content due to different brewing methods and sizes of the serving glasses. Averagely, one 8-fluid-ounce (237 ml) cup of brewed coffee contains from 95 to 163 mg of caffeine.

Drip coffee bought from different shops may have more or less caffeine. For example, a single venti drip coffee from Starbucks contains more caffeine than an average cup of Americano.

Cold Brew

With cold brew, we usually refer to the coffee concentrate obtained by a long-brewing process. To get this liquid, you need to use a higher-than-normal coffee-to-water ratio. As you can imagine, this automatically leads to a higher caffeine concentration.

However, no one usually drinks cold brew on its own, because of its bitter and strong flavor. When you dilute your cold brew with water or milk, these liquids make caffeine lose part of its strength.

Nevertheless, there are many cold brews sold as ready-to-drink beverages which maintain their high levels of caffeine.

Common Reasons Why Coffee Is Not Working for You

Science has demonstrated that there are several common reasons why caffeine might not be working for some individuals. 

Too Much Caffeine

One might think that drinking a lot of caffeine would be the solution for staying alert for many hours. However, if you drink too much coffee you will only end up losing the effect of the precious caffeine.

Once a certain amount is reached (about 400 mg a day for a standard adult), caffeine will only cause side effects. First, you will be way more irritable. Then you might start experiencing sleep deprivation. This means that caffeine will most likely keep you awake all night long, and you will be lying in your bed exhausted yet restless.

Too Little Caffeine

It may be even too obvious, but drinking too little caffeine may not be enough to keep you awake during a hard day at work. 

If you need to drink caffeine for its effect on your brain rather than for the delicious taste of coffee, then you should take into account some key factors, such as your age, weights, and other physical conditions.

On the other hand, different types of coffees have diverse amounts of caffeine. For example, instant coffee might not be enough if you are seeking an energy shot. 

Lack of Sleep

If the lack of sleep has been going on for some time, maybe you shouldn’t seek help from coffee. 

When you are tired, your body produces a chemical called adenosine. This is what makes you sleepy. When you drink coffee, caffeine sticks to these molecules and wakes you up. However, if you are suffering from sleep deprivation, your body produces even more adenosine. All these molecules can push away the caffeine, which will be ineffective. 

You can try with a double shot of Americano to help you stay awake, although we recommend investigating and addressing the root causes of your sleep issues.

High Tolerance Levels for Caffeine

Just like you can train your muscles, you can build a tolerance against caffeine. Itt will take time in both cases, and you will need to take your physical features into account.

If you drink coffee every day, you will surely notice that, after a while, you will need more caffeine to keep you awake. If you are trying to develop better tolerance, then congratulations: your plan is working! Otherwise, if you believe that this can affect your health and sleep, you should slow down. 

It must be noted that it is never a good idea to get your body used to massive amounts of certain substances, including coffee. This can have toxic consequences for many individuals, causing health issues and exposing you to a higher risk of heart attacks.


No, you don’t need to be a superhero for being caffeine-resistant. Science has found a strain in our DNA that regulates how our body processes caffeine. If this is the main reason why caffeine doesn’t wake you up, we are afraid there isn’t much you can do. Even drinking gallons of Americano won’t change the way your metabolism assimilates coffee.

Besides, there are further genes that can affect your relationship with caffeine. They are connected to the levels of sugar in your blood and, consequently, to your cholesterol. Once again, there is no way you can change it, and fighting it by trying different types of beverages or humongous amounts of coffee will never change your genetics.

Other Substances

Everything you eat or drink might affect your ability to metabolize caffeine. Science has demonstrated that medicine, drugs, food and beverage, and more in general, anything you ingest can have different effects on our body works.

For example, caffeine might need to “wait its turn” while your enzymes are busy metabolizing other substances. This keeps caffeine in your system longer, potentially giving your body more energy. On the other hand, smoking cigarettes tends to speed up the rate at which our body processes caffeine. This is one of the reasons why smokers usually can drink more coffee without being affected by it.

What is Caffeine Tolerance?

It is generally believed that caffeine’s stimulating effects may become less noticeable over time because our body becomes more tolerant to its effects. This has led many individuals to drink an increasing amount of coffee whenever they feel their brain is less responsive to caffeine.

Does Caffeine Tolerance Exist?

Although caffeine’s effects are only noticeable in the short term, you can effectively develop a certain tolerance quickly. 

Studies have demonstrated that caffeine’s effects on blood pressure, mental alertness, and our overall performance can last in our body for up to 8 days. This means that regular consumption of caffeine can increase our tolerance to its main effects. On the other hand, caffeine withdrawal can cause sleepiness, headache, and lack of concentration. It usually takes only 12-16 hours for these symptoms to first appear.

How to Develop Caffeine Tolerance

Caffeine works by blocking our brain’s adenosine receptors, stimulating the release of stimulating brain chemicals, and increasing alertness. These effects occur within 30 to 60 minutes of consuming any caffeine-based drink and can last for a few hours.

Studies have found that high caffeine doses can block up to 50% of adenosine receptors in our brain. Besides, science confirms that caffeine’s regular consumption can increase the body’s production of adenosine receptors in the long term. This also increases the likelihood of adenosine binding to those receptors, resulting in higher tolerance to caffeine’ effects.

It must be highlighted that caffeine has no nutritional value or taste of its own. This means that you don’t have any reasons to introduce it in your body unless you are interested in its stimulating effects. If you don’t want to develop caffeine tolerance, but you love to drink several cups of coffee during the day, you can try decaf.

How to Overcome Caffeine Tolerance

You have ingested too many cups of Americano, and now you feel like caffeine doesn’t wake you up anymore? Don’t worry. You can overcome your tolerance by decreasing your caffeine intake. Otherwise, you can even try consuming more caffeine than you normally do to overcome your tolerance in the short term.

However, it would help if you didn’t continually increase your caffeine intake, which can disrupt your metabolism. Besides, it has been confirmed that consuming more caffeine doesn’t really produce greater benefits for our body. 

The best solution is to decrease your daily intake of caffeine or consume it less often. If you cannot renounce the coffee taste, you can switch to decaf or drink diluted hot or cold brew.

What Are “Coffee Naps”?

“Coffee nap” refers to drinking coffee before going to sleep instead of letting our body relax naturally. 

When you are awake, your brain builds up a substance called adenosine. Too much adenosine will cause you to feel drowsy and sleepy until you enjoy a good sip of coffee and let caffeine combat the effect of these irritating chemicals. This means that if you are exhausted and take a regular nap, you will temporarily get rid of your adenosine, but your brain receptors will be ready to build up more as soon as you wake up. By drinking coffee, you are asking caffeine to block all adenosine from connecting to your brain.

How to Take a Coffee Nap

Averagely, it takes about twenty minutes for caffeine to affect our body. Of course, it may take longer if you have already built a certain tolerance. 

Once the caffeine has entered your metabolism, you should find a place to rest. However, you want to keep your naps short, or you might enter the so-called sleep inertia, which is deep sleep. After twenty minutes, you should wake up in time for caffeine to hit your brain and clear all adenosine from it.

Coffee naps can be a good way to quickly recover your energy whenever you have a fifteen-to-twenty-minute window to sleep. Besides, all you need is caffeine, so you don’t even have to drink coffee: anything with caffeine will do.

However, for coffee naps to work properly, you should consume your caffeine fast. This means you should chug the content of your mug in no more than one minute, leaving no room to enjoy the taste of your drink. This is one of the reasons why many coffee lovers don’t do this type of naps. If you are passionate about coffee’s bold and intense taste, you surely don’t want anything to spoil the pleasure of your coffee break.

The “ADHD Myth”: Is It True?

Caffeine is a substance that helps us get going through the day. However, it is also a psychotropic drug, which can alter our mental state. Science has studied how caffeine can lessen some of the ADHD symptoms in adults, such as hyperactivity, inattention, and impulsivity.

This discovery shouldn’t be surprising. ADHD symptoms are typically managed with prescription stimulants, which target our central nervous system and improve concentration. Just like these medications, caffeine acts as a mild stimulant. 

ADHD is caused by structural and chemical differences in the brain of some individuals, which are the results of genetics and environmental triggers. Caffeine works on ADHD in two ways:

  • It blocks the adenosine built up by the brain and suppresses arousal.
  • It manipulates the production of dopamine. As a result, the brain’s ability to focus increases, and the individual experiences an overall boost in their mood.

It must be underlined that caffeine isn’t an effective ADHD medication. This means that you should always speak with your doctor if you believe that coffee and caffeine, in general, is affecting your concentration, your mood or your health.

For many individuals, caffeine is the perfect spark of energy to wake up and feel better when tired. Others say that caffeine does nothing for them. If you are one of those people, there may be a handful of reasons why caffeine doesn’t wake you up.

For example, genetics may play a significant role. Or, maybe, you have just built a high tolerance against caffeine.

Whether the reasons why caffeine is not doing much for you, coffee is indeed one of the most delicious beverages, which should be primarily consumed for its aroma rather than its effects on our body.