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How Long Does Caffeine Stay in Your System?

Question is, How Long Does Caffeine Stay in Your System? Drinking a cup of coffee or tea in the morning gives you the energy to start your day. Caffeine, the main ingredient in these two drinks, boosts your energy, improves alertness, combats sleepiness, improves your mood, increases your heart rate, and increases your blood pressure. These effects usually reach peak levels within 30- 60 minutes after consumption. How long these effects will last depends on how long the stimulant remains in your system.

Well, the half-life of caffeine is estimated to be anywhere from four to six hours on average. This explains why you continue to experience the effects of coffee or tea hours after the initial consumption. The other half-life is usually much longer as its effects are estimated to last more than 5 hours. Some people may take about 8 hours to clear it from their system while others take more than 1-2 days.

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However, this is dependent on various factors.

Factors Affecting How Long Caffeine Remains in the System

How long the stimulant lasts in the system is purely dependent on a number of factors such as dosage consumed, individual factors (age, body weight, genes, general health), how often it is consumed, and drug interaction.

1. Amount Consumed

The amount of caffeine consumed generally affects how much it remains in the system.

The higher the intake, the longer it will take to clear from your body and vice versa.

2. Individual Factors

Various individual factors also affect the length of time your body takes to fully eliminate the stimulant.


Adults clear the stimulant from their systems much faster compared to young children.

Seniors take longer to metabolize it, meaning that it takes longer to clear from their systems.


The speed at which caffeine is metabolized and cleared from the system also depends on an individual’s genes.

Some people with specific genes clear the stimulant faster from their systems compared to others. Research indicates that clearance in some individuals with certain genes may be up to 40 times quicker than those with others.

For example, individuals with a specific variation of the gene PDSS2 metabolize it much slower compared to others.

Height/Weight/Body Fat

Tall and heavy individuals with more body fat generally metabolize the psychoactive drug faster as compared to short and light individuals with less body fat.

High amount of body fat is especially known to increase the metabolism of an individual, thereby increasing the rate at which caffeine is removed from the system.

• Basal Metabolic Rate (BMR)

Individuals with faster Basal Metabolic Rates metabolize the stimulant much faster than those with low BMRs.

• Liver/Kidney Function

Individuals with impaired liver or kidney function eliminate the stimulant from their systems much slower compared to those with healthy organs.

This is due to the fact that both organs play an important role in the metabolization and elimination of caffeine (and other drugs).


Research indicates that the half-life of caffeine in smokers is 2.5 hours, which is much less compared to 5 hours of non-smokers.

Because of this, smokers tend to clear the stimulant much faster than non-smokers.


The clearance rate of caffeine in pregnant women is slower compared to non-pregnant women.

3. Frequency of Intake

It takes longer for caffeine to be metabolized and eliminated from the system in people who frequently take the stimulant compared to those who don’t.

So if a person drinks 5 cups of coffee a day, it may take longer for their body to eliminate the high amount of caffeine ingested compared to a person who only takes 2 cups.

4. Drug Interaction

When taken alongside caffeine, some drugs are known to speed up the clearance time while others prolong it.

Bottom Line

While caffeine does a great job improving your mood and increasing your alertness, it’s important to limit your daily consumption to prevent possible adverse effects.

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