How Long Does Caffeine Last: 4 Constructive Ways to Reduce its Effect

How long does caffeine last
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While at times contributed by guest authors, our content is medically reviewed periodically by professionals for accuracy and relevance. We pride ourselves on our high-quality content and strive towards offering expertise while being authoritative. Our reviewers include doctors, nurses, mental health professionals, and even medical students.


Everyone consumes caffeine for a lot of different reasons and the question ‘how long does caffeine last’ provides a different answer for everyone. Before looking at how long can caffeine lasts let’s know more about caffeine in detail.


Caffeine is a drug, which is bitter but when mixed with the right ingredients can make up a delicious drink.

Caffeine stimulates the central nervous system, the heart, the muscles, and the blood pressure control regions and is known to cause energy boost in the body.

Sources of Caffeine

Caffeine is known to provide an instant jolt of energy and increase the alertness of our body. It is found naturally in over sixty plants including tea leaves, coffee beans, cacao pods, kola nuts, cocoa, and guarana.

Chocolate and protein bars also contain caffeine in them, even some medicines like painkillers, cough syrups, weight reducing tablets have caffeine in them.

  • Coffee

A cup of coffee contains 96 mg of caffeine, an espresso shot has 64 mg of caffeine, instant coffee contains 62 mg of caffeine whereas, decaffeinated coffee has only 2 mg of caffeine in it (Decaf coffee still has some amount of caffeine in it).

How long does coffee last
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  • Tea

Green tea and white tea has 70 mg of caffeine present in them whereas black coffee contains almost double of it (close to 150 mg).

  • Chocolates

White chocolates have no caffeine present in them. The darker the chocolate the more is its caffeine content. Dark chocolate has about 12 mg of caffeine present in them. Milk chocolates have 6 mg of caffeine.

  • Energy and soft drinks

Soft drinks usually contain less caffeine than energy drinks. Caffeine in soft drinks and energy drinks is not naturally present, it is added artificially and is known as synthetic caffeine. A can of Coke and Pepsi has about 32-38 mg of caffeine present in them. Mountain dew tops them by containing 54 mg of caffeine.

How long does caffeine last
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Energy drinks like Red Bull and Monster Energy contain 110-160 mg of caffeine in the can. Energy drinks are known to have a higher concentration of caffeine up to 350 mg.

Uses of Caffeine

Caffeine is a very useful drug, following are the various ways in which caffeine is used.

  • When taken together with other medicines, caffeine has a positive effect on the body. For example, caffeine taken with painkillers like ibuprofen is likely to reduce the pain more effectively than the pain-killer alone can do. It also helps in migraine pains and headaches.
  • Mental Alertness: Caffeine stimulate the central nervous system, it increases the flow of different hormones like adrenaline and cortisol which in turn increases the alertness of the brain.
  • Increased athletic performance: Caffeine is used by athletics to increase their exercise performance as caffeine allows them to keep fatigued at bay during exercise and increase endurance.

Caffeine Intake

Yes, caffeine is useful for many purposes but caffeine intake should be regulated so that caffeine overdose does not take place or worse, you do not get caffeine addictive.

According to the Food and Drug Administration(FDA), 400 mg of caffeine intake per day is safe for your body.

If too much caffeine is taken and caffeine intake surpasses the normal levels, the following symptoms are seen:

  • Headaches
  • Sweating
  • Increase in heart rate
  • Insomnia
  • Increase in breathing rate
  • Nausea
  • Feeling of shakiness

When experiencing these symptoms, the best way to treat them is by drinking water as caffeine cannot be flushed out from your body. Drinking water speeds up the process of caffeine leaving your body naturally.

How long does caffeine last

Everyone who consumes caffeine or is considering starting to consume caffeine always asks ‘how long does caffeine last’. The answer to this question is answered below.

The instant spike of caffeine is felt by most individuals within 10-15 minutes after eating it. After about one hour, your caffeine consumption is most certainly at its peak. About half of the caffeine you consumed 6 hours ago is still in your body. This is known as the half-life of caffeine. The effectiveness of caffeine usually decreases once it completes its half-life.

It is advisable to consume caffeine six to eight hours before sleeping so that the half-life of caffeine is completed which reduces its effect and does not cause a problem in falling asleep.

How long does caffeine last
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It is estimated that the answer to the question of ‘how long does caffeine last’ is, it takes up to a total of 10-12 hours for the caffeine to flush out of your body completely. People who have a high tolerance to caffeine may not feel the effects of caffeine after its half-life. Those who have recently started consuming caffeine may feel its reaction until it is completely flushed out.

Our bodies metabolize caffeine in different ways depending on various factors like:

  • Caffeine Dose Size

Whether you have a high tolerance or low tolerance of caffeine the question of how long does caffeine last will significantly depend on the size of the caffeine dose.

How long does caffeine last
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For example, if you take a cup of coffee which usually contains about 90-95 mg of caffeine, and your body’s half-life is around five hours, very little to no amount of caffeine will be present in your body after ten hours. But if you ingest 4 eight ounces energy drinks, whose caffeine content is roughly around 400 mg, its effect will still be present after ten hours.

  • Metabolism

Caffeine is digested and metabolized in your liver by a group of enzymes. Genetics determines how much of each enzyme you make. This implies that some individuals break down Caffeine very slowly, while others break it down so quickly that they scarcely notice its effects.

The height and weight factors of your body also affect the answer to the question of ‘how long does caffeine last’ in your body.

Caffeine sensitivity also comes into the picture, If you are hypersensitive to caffeine, even a modest quantity might cause you to get the jitters, which include feelings of dizziness, restlessness, and overall discomfort. However, even if you have never had caffeine before, and you are hypersensitive, you won’t feel much of a stimulating impact from it at typical doses.

  • Caffeine Tolerance

It takes time for something to become a habit and creating a tolerance of caffeine is the same. The more you consume caffeine, the more tolerant you become to its effect, and hence the answer to the question of ‘how long does caffeine last’ will vary accordingly.

Those who have become tolerant to caffeine may require to consume more and more doses of caffeine to feel its effects.

People who have just started consuming caffeine in any form whether it may be in brewed coffee or espresso shots may feel its effect more adversely.

  • Other Substances

Other drugs you ingest can alter how Caffeine is broken down in your body, affecting your half-life of Caffeine, and hence the answer to the question ‘how long does caffeine last’ varies. Hormonal contraceptives, for example, can slow down the rate at which Caffeine is processed, making you more susceptible to the effects of caffeine.

Regular smokers, on the other hand, have a Caffeine half-life of around three hours, making them very less sensitive towards the consequences of caffeine.

How long does caffeine last
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Other medications and chemicals can affect how Caffeine is processed, so check how it interacts with any medications you are taking before.

Speeding Up the Half-Life of Caffeine

Sometimes in the need to feel energized and alert, people consume way more caffeine than they can handle which results in the feeling of restlessness and shakiness. There is no way in speeding up the half-life of caffeine, once it is consumed, it completes its whole cycle.

But if you feel the negative effects of caffeine are hindering your daily life activities, the following ways can be used to make you feel a little better:

  • Drinking-Water

As we know, caffeine can not be flushed out of the body completely, but drinking water has its benefits. Caffeine consumption can sometimes leave your body dehydrated which worsens the effects of caffeine.

How long does caffeine last
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Drinking water helps in keeping your body hydrated and in turn minimizes some of the negative effects of caffeine.

  • Eating Food

Caffeine suppresses the body’s appetite and consuming caffeine on an empty stomach is another calling for a disaster. Increased levels of blood pressure, feeling of nausea, upset stomach, and anxiety can occur if you do not eat before or after having caffeine.

How long does caffeine last
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When you take caffeine with a meal, your body’s digestion of caffeine is slowed, making you less likely to feel jittery.

  • Exercising

Exercising does not speed up the process of breaking down caffeine any faster but it sure does help in the burning of energy which is created by the release of adrenaline. When caffeine is consumed it releases a set of hormones and adrenaline is one of them.

  • Plant-Based Energy Drink

Instead of opting for energy drinks that have synthetic caffeine in them to increase your alertness and concentration, try drinking plant-based energy drinks.

How long does caffeine last
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They are made with organic caffeine and infused with green tea and allow the same benefits as synthetic energy drinks with less harmful effects.

Caffeine Addiction

We have now seen the various factors that answer the question of ‘how long does caffeine last’ in our body, let’s move on to the next important topic which is can caffeine become addictive?

Caffeine tolerance develops in many people. This implies that your body adjusts and becomes accustomed to consuming caffeine daily. You may discover that you need to gradually increase your caffeine consumption to attain the necessary alertness and concentration results.

But there is a difference between being addicted and becoming dependent on something. Caffeine can cause physical dependency, although it isn’t strictly an addiction. It increases dopamine levels, but only slightly. Caffeine, after all, gives you warm feelings as well as an increase in alertness, which most caffeine users love.

Caffeine Withdrawal

When you have become dependent on caffeine and quit consuming it abruptly it can cause caffeine withdrawal. Caffeine withdrawal symptoms include the following:

  • Irritability
  • Nausea
  • Headaches
  • Fatigue
  • Anxiety
  • Difficulty in concentrating
  • Tiredness
  • Mental fogginess
  • Mood changes

The more you are used to drinking caffeine, the more severe the withdrawal symptoms will be. Withdrawal symptoms appear 12 -24 hours after the last caffeine use and can continue anywhere from 2 to 9 days.

The simplest strategy to overcome your caffeine addiction is to gradually lower the quantity you consume. This allows your nervous system to adjust to life without the medication.

Consuming caffeine for increasing alertness and feeling energized is not the wrong thing but getting dependent on it can cause harmful effects on your body.

Who Should Avoid Caffeine

Caffeine is freely available in all parts of the world but that does not mean its use should be exploited as it can cause harm to your body. Intake of caffeine should be regulated especially by the following people:

  • Pregnant Women: Caffeine use can raise the chances of miscarriage, a difficult birth, and a child born with low birth weight.
  • Breastfeeding Women: Some amount of caffeine can pass along to the baby, which is not healthy for the baby.
  • Children: Children can be sensitive to the effects of caffeine and hence should consume less or better yet no caffeine at all.
  • People suffering from high blood pressure.
  • For people having anxiety, Caffeine can make the feelings of anxiousness worse.
  • People suffering from sleep disorders like insomnia should refrain from consuming caffeine.
  • People on medications should avoid caffeine as it can hinder the process of the medications on your body.
  • People having heart conditions, like irregular heartbeat should avoid the consumption of caffeine.
  • For people having glaucoma, the pressure inside the eye increases when caffeine is consumed and hence should be taken cautiously.

So, How Long Does Caffeine Last?

The answer to the question of ‘how long does caffeine last’ is- it depends. It depends on various factors and the answer varies from person to person.

Caffeine is not bad for health if taken in regulated doses but, once it is taken in a higher amount than necessary it can become quite unhealthy for your body.

Along with regulating doses of caffeine, natural caffeine should be consumed more instead of synthetic one as they increase your focus and concentration powers naturally.

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While at times contributed by guest authors, our content is medically reviewed periodically by professionals for accuracy and relevance. We pride ourselves on our high-quality content and strive towards offering expertise while being authoritative. Our reviewers include doctors, nurses, mental health professionals, and even medical students. -----------------------------------

Any information found on the site does not constitute legal or medical advice. Should you face health issues, please visit your doctor to get yourself diagnosed. Icy Health offers expert opinions and advice for informational purposes only. This is not a substitute for professional medical advice.


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