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How Long Does Coffee Stay in Your System? Here Are the Facts

I know you love coffee. Aside from its lovely aroma and taste, it is one of the top sources of antioxidants and it comes with incredible benefits. Improving memory, reducing fatigue, and enhancing mental function are some of the known benefits of coffee consumption.

This is not all. Caffeine can also help improve reaction time and short-term memory, according to studies.

The list of the good things about coffee can be longer. But since we’re talking about coffee and caffeine’s effects on the body—whether good or bad—there is one question that you may be asking, “how long does coffee stay in your system?”

Let’s answer this important question for you.

Caffeine: What Is It?

sleepy woman stirring coffee

Before we discuss how long coffee lasts in the body, let’s first understand what caffeine is. This is the stimulant in your coffee that helps reduce tiredness and boost energy. For many people, caffeine serves as an ingredient to wake them up and help start the day in the best form.

A closer look reveals that caffeine is a white and bitter substance that occurs naturally in more than 60 plants, including coffee beans, tea leaves, and the cacao leaves/pods used to make chocolate. The US Food and Drug Administration (FDA) has classified caffeine in two ways: as a food additive and as a drug.

How much caffeine is in your cup of coffee?

The amount of caffeine in your drink or food varies, depending on several factors. If you’re taking a cup of coffee, the amount of caffeine depends on the brand, type of beans, and the preparation.

In most cases, a cup of coffee can have as little as two mg of caffeine to as high as 200 mg. The average caffeine in a cup of tea is about 40 mg, while energy drinks contain between 30 mg and 60 mg.

How Long Does Caffeine Stay in Your System?

pouring coffee in a cup

To understand how long caffeine stays in your body and how to absorb all its health benefits, let’s look at its metabolism and how long the effects usually last.

Caffeine Metabolism

When you consume coffee, caffeine is metabolized in the liver by cytochrome p450 enzymes. These enzymes are responsible for clearing over 90% of the caffeine.

This rate of metabolism depends on factors such as race, diseases, diet, and exposure to inducers. For example, a high intake of brassica vegetables and broccoli increases caffeine metabolism and clearance from the liver.

You might want to cut down on alcohol intake because it damages the liver and ultimately slows down the metabolism of caffeine. Smoking and pregnancy also reduce the uptake of caffeine in the body.

When Does Caffeine Effect Peak?

Now, onto the big question about how long coffee stays in your system. According to the American Academy of Sleep Medicine, caffeine’s half-life is about five hours.

Half-life is the time it takes for an amount of material to be reduced by 50%. So, if you take 40 mg of caffeine, it implies that 20 mg will still be in your body after five hours.

caffeine molecular formula

After taking coffee, it is absorbed rapidly, and the effects are expected to peak in about 15 to 45 minutes. However, you can expect to continue feeling the effects of caffeine for up to 10 hours.

People with caffeine sensitivities might experience the effects for a more extended period, at times even days.

The amount of coffee that you take will also depend on the dosage. Let’s say, you took 200 mg of caffeine. It will halve to 100 mg in five hours and 50 mg after another five hours. So, the effect will be less compared to another person who takes only 20 mg. In this case, only 10 mg will be remaining after five hours and 5 mg by the tenth hour.

Because of the long-term impact of caffeine, it is recommended that you avoid consuming coffee at least six hours before going to sleep. So, if you go to bed at 9:00 PM, consider having the last cup of coffee no later than 3.00 PM.

Note: If you feel the effects are too much and want to reduce them, drink water to stay hydrated and take some food. Exercise can also help to hasten the processing of caffeine.

What Are the Effects of Caffeine on the Body?

Caffeine passes into your bloodstream from the small intestine and stomach, and then, stimulates the central nervous system to make you feel alert and awake. Once in the brain, it helps to enhance dopamine signaling.

Dopamine is the chemical responsible for controlling emotions, motivations, and movements. So, when signaling increases because of high levels of caffeine, you feel more alert and energetic.

Here are more specific effects of coffee and caffeine on the body:

It Helps With Burning Fat

If you are wondering about a good way to burn fat, caffeine might be the solution you are looking for.

Studies have demonstrated that caffeine can help boost your metabolic rate by up to 11%, consequently helping to burn fat. For obese people, caffeine can help stimulate fat burning by up to 29%.

Improving Physical Performance 

When caffeine reaches the nervous system, it signals the fat cells to break down fat and further increase adrenaline (epinephrine) in the blood.

Epinephrine, also known as the fight-or-flight hormone, prepares your body for intense body action. Consequently, this action can increase your body’s physical performance by up to 12%.

Contains Loads of Useful Nutrients 

When you take a cup of brewed coffee, it contains many of the core nutrients in beans. Although the nutrient levels might be lower compared to other foods, taking several cups every day means they can accumulate in your body pretty fast.

  • Niacin (vitamin B3) and magnesium: 2% of the Reference Daily Intake (RDI)
  • Pantothenic acid (vitamin B5): 6% RDI
  • Riboflavin (vitamin B2): 11% RDI
  • Manganese and potassium: 3% RDI

Might Help Lower the Risk of Type-2 Diabetes 

Type 2 diabetes is a serious problem that is affecting millions of people globally. The problem is characterized by high blood sugar levels resulting from reduced ability to secrete insulin or insulin resistance.

Studies have shown that coffee drinkers have managed to cut down the risk of type-2 diabetes significantly. It is estimated that you can reduce the risk of getting diabetes by up to 50%.

Caffeine Can Help Protect Your Liver 

Your liver is one fantastic organ because it carries out hundreds of critical functions, such as bile production and the creation of hormones. However, several diseases—such as fatty liver disease and hepatitis—that affect the liver can result in cirrhosis.

Interestingly, drinking coffee can help with cirrhosis protection. If you take four cups of coffee per day, it is possible to lower the risk of suffering liver cirrhosis by more than 60%.

Can Help You Live Longer 

Today, almost everyone is wondering how to live longer. Well, you might have just come to the right answer; by drinking more coffee.

Observational studies show that coffee drinkers are at lower risks of death compared to non-drinkers. If you are a man, caffeine can help to cut down the risk of death by 20%. For women, the risk of death is reduced by a bigger margin of 26%.

Taking Caffeine: What Levels Are Considered Too Much?

In the U.S., an average adult takes about 200 mg of caffeine—the equivalent of two 5 oz of coffee—per day. Taking up to four cups of coffee (400 mg of caffeine) does not pose any significant challenge. However, we need to clarify that caffeine’s effects are not the same for everyone, depending on the person’s sensitivity, gender, and body size.

If you are highly sensitive to caffeine, even low amounts of caffeine can result in serious issues, such as insomnia, anxiety, and restlessness. In other cases, some people feel sleepy immediately after drinking coffee.

Health and nutrition experts believe that more than 600 mg of caffeine (equivalent to five-seven cups of coffee) in a day is considered too much.

The best practice is to take a cup in the morning and mid-morning for an energy boost and alertness at work. If you’re into the keto-compliant bulletproof coffee, there is also a limit to that. Read our guide here.

Also, find out: Is coffee dehydrating?

Who Should Avoid Caffeine?

For most of us, coffee is the go-to option for a perfect start of the day or when we want to focus on something. However, it is not recommended for everyone, especially in heavy doses.

If you have any of the following conditions, it will be a good idea to avoid caffeine:

  • Disorder like insomnia
  • Breastfeeding (to some extent)
  • Pregnant
  • Ulcers
  • Chronic headaches or migraines
  • Taking antibiotics and stimulants that can have interactions
  • Anxiety
  • Irregular heartbeat

If you have any of these conditions and still want to have some coffee, consider talking to your doctor for further advisory. If you are fasting, find out if it’s OK to drink coffee while fasting.

Also, remember that caffeine is never good for your dog. Check out our guide here.

Final Thoughts

How long does coffee stay in your system? In this post, we have demonstrated that the average person experiences a half-life of caffeine in approximately five hours, but the peak effect comes earlier at 15-45 minutes of taking a coffee beverage.

However, your body metabolism, caffeine dose, and other drugs you might be using might impact how long the effects will be felt in your body. In higher doses, coffee will take longer in your body than in low quantities.

Remember that it is always a good idea to avoid taking excessive caffeine. To reduce the effects of too much caffeine, take more water to stay hydrated, eat food, and do more exercise. So, make it a habit to only drink the right amount of coffee to avoid any health problems.

Krista Haws

Known among her friends as 'the caffeine fiend', Krista loves all things coffee. From an extremely short, strong espresso to a 3 day cold brew, Krista loves them all.

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