Can Caffeine Make You Sleepy?

People use caffeine drinks as a stimulant; however, some people do not find the results they desire. We will discuss potential reasons to find the answer to whether caffeine makes you sleepy and how long it takes to kick in.

Most people drink caffeine to increase alertness, focus, and energy, whereas in some cases, it works vice versa and makes them feel tired instead. One should be aware of different reasons that make you sleepy and provide tips to avoid drowsiness.

Caffeine stimulates your central nervous system and makes you feel energetic, but the effects differ for everyone. We react to caffeine differently, as one person may intake a lot of caffeine but experience minimal effects. In comparison, one person could drink only one cup and experience adverse effects while elevating heart rate, jittery feelings, and digestion problems.

Caffeine can cause harmful effects instead of wakefulness, which can cause people to become sleepy and unfocused. Somehow we consider caffeine a popular drug, the world’s most popular psychoactive drug. We will search more about how caffeine includes sluggishness instead of alertness.

Why does caffeine make me tired right away?

Knowing why an energy drink is making you more exhausted than before is imperative. The common thing is that caffeine can wake you up, but it never works the same for everyone, and one can feel more tired after intake.

The typical effect is that caffeine can make you feel tired and sleepy. The natural and artificial forms of caffeine can be chemically identical, but they both work similarly. It is all about stimulants that work with the essential chemicals of the brain. Individual differences in caffeine metabolism can tire you after taking caffeine in any condition. Some of the reasons we will mention here are why caffeine immediately makes me tired.

  • Sleep deprivation
  • It can cause dehydration
  • It may lead to blood sugar changes
  • Adenosine levels
  • Tolerance to caffeine
  • Toxic chemicals
  • Caffeine can affect stress
  • Caffeine metabolism
  • Genetics

Sleep deprivation

Most Americans have sleep deprivation issues and not receiving proper sleep every night. Caffeine can not provide an adequate substitute for rest as sleep deprivation can reduce alertness, slow the response and negatively affect thinking.

If anyone drinks more coffee to overcome tiredness, it can fire back and negatively impact sleep, making you sleepy the next day. Turning to caffeine to fix the effects of sleep can create more negative effects. After taking caffeine, you can get even more tired, disrupting your sleep and becoming more tired in the long run.

It can cause dehydration

The nature of coffee is diuretic, which means it helps the body to rid of water. Coffee drinkers can get into a vicious cycle to make them frequently go to restrooms. Once the body loses water, it causes dehydration and decreases blood volume. That will make blood travel slowly in veins and arteries, causing less oxygen delivery to the body.

Without enough oxygen, one can experience exhaustion. To combat tired feelings, one wants to intake more caffeine, and it goes on, resulting in dehydration and fatigue. Dehydration can cause fatigue. Therefore, one must try to stay hydrated.

Even using coffee is a diuretic, which increases your need to urinate, leading to fluid loss. Mild dehydration can make you experience fatigue, which can decrease cognitive performance and impair memory with increased anxiety and tension. In addition, dehydration can cause a higher heart rate and low blood pressure.

Dehydration can lead you toward loss of salt and water from your body. One can quickly start feeling the effects of fatigue, dizziness, thirst, dry mouth and skin, and confusion.

One can avoid this by drinking a moderate amount of caffeine and monitoring caffeine intake, which should be 500mg or less daily. Avoid other caffeinated beverages, including energy and soft drinks, and count on more smoothies, berries, melon, or any fruit and vegetable. Focus on hydration during the hot summer months, especially if you are sick or have an exercise routine.

It may lead to blood sugar changes.

If anyone drinks coffee or coffee-flavored drinks, they usually contain a high amount of sugar, and you feel boosted if the quick energy runs out. Most coffee creamers come with high levels of sugar. While using coffee drinks at a local cafe, avoid whipped cream, honey, flavored syrup, or any chocolate.

Such sugar materials contain refined sugar that can come with a sugar crash after metabolism. A sugar crash happens when someone consumes so much sugar, and the body starts producing insulin to offset it, which causes a significant drop in blood glucose.

Blood glucose enhances body energy, so people prefer to drink coffee before starting any workout. The drop in blood sugar can cause sleepy and sluggish feelings, with anxiety, mood swings, hunger, and dizziness.

It can have adverse effects on your body to tolerate glucose. It makes you more sensitive towards sugar and can increase temporary surge in blood sugar, commonly in diabetics or people with prediabetes.

To prevent such effects, one must limit the sugar intake amount that comes with drinking coffee and other energy drinks you consume each day. If someone goes through a sugar crash, one can counterattack the effects with healthy snacks, including hard-boiled eggs, seeds, nuts, and yogurt.

Adenosine levels

Adenosine is a chemical in the brain that manages the body’s internal clock. This chemical is released in larger quantities when someone suffers from sleeplessness; adenosine will bring sleep. In this case, caffeine will promote alertness, reduce tiredness, and block adenosine receptors.

The level of adenosine fluctuates throughout the day, which generally increases during wake days and drops when we sleep. Under normal circumstances, the adenosine receptors in the brain slow the brain activity to prepare for rest.

When someone consumes caffeine, it blocks these receptors and prevents the brain from receiving adenosine; it builds the chemical. After wearing off the effects of caffeine, it accumulates adenosine floods through the brain and causes fatigue.

Research suggests that the body compensates for the impact by increasing the sensitivity to adenosine. After consuming caffeine, it can block receptors and prevent the brain from receiving adenosine.

Tolerance to caffeine

Physically active adults experience fewer caffeine effects when they consume fifteen days of regular consumption. Caffeine intakers may build a tolerance, preventing them from binding with receptors.

Excessive use of caffeine can build up tolerance over time, and even tolerance level change due to various factors, including weight, age, and medication. Caffeine is addictive; the more you drink, the more your feel alert and focused.

Caffeine prevents adenosine from binding with receptors, and the body can start to produce more adenosine receptors. Although research on caffeine tolerance is inconclusive, regular consumption changes the rate of absorption or metabolism.

Your body may start stimulating more adenosine receptors. However, research on caffeine tolerance still needs to be more conclusive, as other research shows that regular consumption does not change the rate of absorption or metabolism.

Toxic chemicals

Mycotoxins are naturally toxic chemicals that grow on coffee due to molds in food. In some cases, these are very harmful to the body, causing dangerous reactions which can cause inflammation of the lungs, difficulty breathing, and high fever.

One must avoid consuming mycotoxins by choosing only WHO-recommended commodities and things adequately dried and stored with no effective mold growth. Go for the wet-roasted coffee beans, which grow at higher elevations and can mold less likely in more relaxed and dry climates.

Avoid coffee blends as you need to learn about their origin. They usually come from unknown sources, so we can not ensure the quality of the beans or even the processing process. These toxic chemicals are unsafe for human beings and can lead to chronic fatigue syndrome.

Make sure that the concentration of mycotoxins is acceptable according to legal limits. With chronic fatigue, one can feel tired after resting and experience sleep problems. Other symptoms may include dizziness and lack of thinking and concentration.

Caffeine can affect stress

Stress is a source of keeping you awake all night and can cause stress-induced insomnia. We know well that stress can make you feel fatigued in response to the stress hormone cortisol. This chemical can signal your body to stay on high alert; in response, people can perceive stressors.

One more essential component of our body is epinephrine, or epinephrine, which travels throughout the body and makes the heart speed up and breathe faster, increasing alertness.

Ingesting caffeine doubled the levels of epinephrine and cristol regardless someone consumes caffeine regularly. If you consume the same amount of caffeine daily, you feel stressed every day, but still, stress comes with sleeplessness.

Caffeine metabolism

Not everyone can metabolize caffeine. Similarly, some individuals metabolize caffeine slowly. With the slow metabolism of caffeine, one can feel even more alert. In comparison, if someone metabolizes caffeine quickly, it might not impact that way and lead to feelings of sleepiness sooner.

Multiple factors impact the person who metabolizes caffeine. Smoking also speeds up caffeine metabolism, whereas liver disease and pregnancy will slow caffeine metabolism.


Researchers work on genetics and the impact of how individuals respond to caffeine. Specific genes could make you more sensitive to caffeine’s adverse effects, including sleep disruption and anxiety.

Caffeine negatively affects your sleep which might increase daytime tiredness. One must drink plenty of water along with an intake of coffee and other coffee beverages.

How does it take for caffeine to kick in?

Everyone wants to know when to take caffeine or drink coffee and how much caffeine takes to kick in, as caffeine takes some time to get into proper form. Coffee is a must-have for many people to wake up and keep going throughout the day, as coffee contains caffeine, a stimulant that gives people the feeling of alertness.

Most people in the United States brew coffee at home or go to some coffee places to fix their daily coffee intake. They want to know how long it will take caffeine to kick in, and we can say it can take twenty minutes to one hour to kick in, along with a few variables such as how quickly you intake it, how much you intake, and type of body which speeds up or delay the impact.

Unless caffeine hits their bloodstream, one may feel tired or incapable of functioning at high levels. One can see its effects of kicking in within ten minutes, but the peak time to work could be forty-five minutes, the right time when caffeine will fully enter your bloodstream. At the same time, it can take several hours to dissipate the impact of caffeine.

A recent study measuring the caffeine effect on the human body revealed that forty-five minutes are for the maximum caffeine concentration to reach in the blood. Still, the level reaches half this concentration after just a few minutes.

In other words, it takes 10-45 minutes to make caffeine effects in full stream, including energy boost, optimal mental performance, happy mood, and enhanced physical performance. However, it depends on your body, and you can also get some adverse effects, including anxiety, depression, and jitters.

How long can caffeine stay in your system?

According to various research, the half-life of caffeine in healthy adults could be 1.5 to 9.5 hours. Half-life is the duration of an active life of a drug period, required for the concentration and amount of drug in the body to reduce by one-half.

The half-life of a drug concerns the amount of the drug in the plasma, and it depends on how quickly the drug eliminates from the plasma. Half of the caffeine dosage consume and clear from the body in five hours for most people. At the same time, finishing it takes 8.25 hours to 2.18 days.

Various factors can affect the outcome of caffeine:

How much coffee you drank

Caffeine is way more effective as it takes longer to kick in levels. It will take longer to effect if you are sipping a 4oz cup of coffee compared to extra large cold coffee. To get more effect, we suggest you increase the quantity of intake or drink faster.

How fast you drank coffee

If you want to speed up the effect of caffeine in a few minutes, drink the coffee faster. If you drink a small amount of coffee faster, slowly sipping a big cup may give you a different buzz than you want.


If the coffee kicks in slower or faster than usual, it depends on the metabolism. If the liver metabolizes the coffee slower, you need one to two hours to effect it. On the other hand, if it metabolizes faster than you feel it within 15-20 minutes.

Can caffeine help you sleep?

One can extract caffeine from plants as natural sources, including coffee beans, leaves, and cocoa beans, and produce it synthetically. However, caffeine is a drug that can promote alertness.

However, caffeine can act as an adenosine receptor antagonist as a stimulant, whereas adenosine promotes sleepiness, and caffeine blocks adenosine to keep someone sleepy.

Caffeine affects quickly and reaches the blood within 30 to 60 minutes with a half-life of 3-5 hours. Usually, we consider caffeine an effective alarming agent if we intake it with a regular dose of 50-200mg, with positive effects on reaction times, mood, and physical and mental performance.

Higher doses which could be 500-600mg, will affect a low dose of medication instead of just caffeine. If someone consumes it daily, it will not work as a stimulant, and the body can build resistance against it.

On the other hand, caffeine intake could disrupt sleep and make it hard to sleep. Caffeine can delay the timing of the sleep-fixed body clock, reducing the total sleep time.

Caffeine affects us more when we consume it earlier in the afternoon, and if we use it almost six hours before bedtime, it can reduce sleep by one hour. High caffeine doses have many side effects, including diarrhea, sweating, nausea, increased heart, and breath rate, etc.

Why does caffeine make me sleepy, ADHD?

Having attention-deficit hyperactivity disorder (ADHD) make it difficult to concentrate. People who live with ADHD have difficulty performing specific tasks and get distracted easily, and get more stimuli around them.

They become frustrated while performing tasks and take a long time. Living with ADHD is challenging, and one must get treatment correctly. One can find caffeine in coffee, chocolate, and tea that can impact your brain.

Stimulates body

Caffeine stimulates the body’s central nervous system and boosts the brain’s production, certain neurochemicals known as dopamine control the ability to focus and maintain concentration.

The stimulation can cause a person to feel energetic and not tired. Though sometimes the effect could be damaging, people can feel the sleeping issue or insomnia due to caffeine.

Sleep reduction

Sleep deprivation can cause ADHD-like symptoms, including irritability, forgetfulness, focus trouble, and difficulty controlling emotions; even all these symptoms appear worse. So we suggest people with ADHD should use it in the morning and avoid consuming coffee, tea, chocolate, and soda in the late hours.

Reducing blood flow to the brain

Caffeine makes blood vessels smaller and reduces blood flow; decreased blood flow helps with headaches. Amphetamine medications treat ADHD and make blood vessels more petite, with some similar to those of common ADHD.

Blood flow may reduce the activity of overactive brain regions and allow them to function better and cooperate with the rest of the brain.

Use caffeine for concentration

There must be a very narrow margin of Dopamine to focus on their work. ADHD comes with too low dopamine levels, so caffeine is a stimulant that helps increase dopamine levels.

Adding stimulants will make dopamine levels high, which can even cause agitation and anxiety. People with ADHD can get an adequate amount of Dopamine with stimulants; for this purpose, a few cups of coffee can make a real difference.

Some studies found that caffeine intake can increase concentration in ADHD as it works as a stimulant drug. Some of the more potent stimulants will help to treat ADHD and work as a medication, in other words.

Although caffeine is not as effective as some prescribed medications, caffeine is quite productive for ADHD. Remember that excessive amounts of caffeine can harm children and teens, and we recommend it for adults.

Risks come with caffeine use

Heavy caffeine use is an intake of 500 to 600 mg daily; excessive caffeine may cause the following symptoms:

  • Sleeplessness
  • Irritability
  • Anxiety
  • Insomnia
  • Rapid heartbeat
  • Stomach upset
  • Muscle shakes
  • Tremors

Medication combinations are pretty hard to control, and people using caffeine with the prescribed medications come with various side effects and can cause anxiety, nausea, stomach pain, and difficulty sleeping.

If someone is experiencing anxiety or difficulty sleeping, there is a chance of too much caffeine intake. We will suggest you take caffeine and medication with proper food to avoid stomach pains and sort out nausea.

What makes caffeine stay in your system?

Staying caffeine in your body depends on various factors:


By that time, the faster body can break down caffeine. Usually, the half-life is around five hours, but it could be eighty hours for kids. The caffeine metabolism of seniors aged 65 and above with 1.0 ml/min is 33 percent lower than adults.

Build and body type

It is about common sense as more extensive and taller have a faster rate of caffeine metabolism. If someone has more bad fats, it can help make the metabolism and caffeine clearance faster.


The effects of caffeine metabolism may differ in genetics. Some people process caffeine forty times faster than anything else. It applies to the rate by which the body goes under caffeine clearance.

What could be caffeine withdrawal symptoms?

If anyone consumes caffeine and abruptly stops, they feel the effects of caffeine withdrawal. Caffeine withdrawal comes with sleepiness, headache, nausea, inability to concentrate, and irritability.

One can feel the symptoms 12-24 hours after the last caffeine intake. Symptoms usually depend on the amount of caffeine consumed. However, it depends on how much caffeine you absorb, so the symptoms can last accordingly, whether for a few days or can last for weeks.

If anybody wants to avoid caffeine withdrawal symptoms, do it gradually. Adopt the approach of cutting down things slowly, such as initially cutting down consumption by 1/4th of the total amount.


While seeking the answer, Can caffeine make you sleepy? We have learned that caffeine intake has withdrawal symptoms when someone uses it regularly, including sleepiness, headaches, bad moods, anxiety, and low energy levels.

How long does it take for caffeine to kick in? Stay aware that caffeine usually takes one hour to kick in. However, some variables can change the time frame. Some individuals take caffeine as a pick-me-up but disappoint when it never gets the buzz immediately.

Why does caffeine make me sleepy, ADHD? Some people with ADHD get tired when they drink too much caffeine though the effects of caffeine play a vital role. If someone intakes caffeine throughout the day, then they can have enough problems getting enough sleep. Low caffeine consumption can prove a booster without adverse effects for some with ADHD.

Caffeine has negative and positive attributes and can improve concentration, energy, and alertness. It could consume high doses of caffeine daily and harm your sleep while reducing the quality and quantity of your sleep.