Caffeine Half-Life: How Long Does Coffee Stay in the Body?

Caffeine, also known as coffeine, is a naturally occurring substance found in coffee and cocoa beans, guarana berries, tea leaves and kola nuts, among other things. We most commonly consume caffeine through drinks such as coffee, cola or energy drinks.

Caffeine belongs to the so-called psychotropic substances – substances that affect the central nervous system. Put simply, this means that by consuming caffeine, we feel more awake and focused. Maybe you know this too: in the morning or during an energy low, many people automatically reach for a cup of coffee.

Now it gets a little biological – but don’t worry, explained very simply:

There is a messenger substance in the brain called adenosine. It builds up over the course of the day, binds to adenosine receptors and signals to the body: you are getting tired. Adenosine receptors are found throughout the body, with particularly many located in the brain.

Caffeine is chemically very similar to adenosine. This means caffeine can also dock onto adenosine receptors in the brain and in other parts of the body and blocks them.

This means: adenosine can no longer bind to the receptors. As a result, our brain no longer receives tiredness signals and we feel more awake and focused.

Once the caffeine is broken down, adenosine can dock again – and tiredness returns.

Half-life describes the time the body needs to break down half of the caffeine consumed. The stimulating effect usually starts 15 to 30 minutes after intake and can last for several hours depending on the person. Some people break down caffeine very quickly, while in others it stays in the body much longer.

Various factors influence this, such as genetics, smoking, pregnancy, medication and liver health. We will go into these factors shortly.

In healthy adults, the average half-life of caffeine is around four hours. However, there is a wide range – it can be between two and eight hours.

Example:

We assume a half-life of 4 hours.

• You drink a coffee with about 100 mg caffeine at 2:00 p.m.
• At around 6:00 p.m., about 50 mg are still in the body
• At around 10:00 p.m., about 25 mg
• After that 12.5 mg – and so on.

This means: even if the noticeable effect has long faded, there is often still caffeine in the body, which is gradually broken down further.

Our protein coffee is the ideal alternative to a classic cup of coffee. It combines coffee enjoyment with high-quality protein and thus supports a protein-rich diet.

1. Enzyme activity

How quickly caffeine is broken down depends, among other things, on certain enzymes in your liver. These liver enzymes are responsible for metabolising caffeine. Since their activity differs from person to person, the half-life also varies.

2. Genetics

Genetic differences influence how quickly caffeine is broken down. Some people break down caffeine very quickly, others much more slowly – regardless of body weight. That is why some people are still awake for a long time after an evening coffee, while others can fall asleep without any problems even after several espressos shortly before bedtime.

3. Pregnancy

During pregnancy, caffeine breakdown slows down significantly, especially in the second and third trimester. As a result, caffeine stays in the body longer and its effect lasts longer.

4. Medication

Various medications , such as estrogen-containing oral contraceptives and certain antibiotics (particularly ciprofloxacin), can speed up or slow down the breakdown of caffeine and thereby influence how long caffeine remains in the body.

5. Smoking

Nicotine influences the activity of certain liver enzymes and can speed up caffeine breakdown.

6. Liver diseases

Since caffeine is mainly broken down in the liver, liver diseases can significantly slow down caffeine breakdown. As a result, caffeine remains in the body longer and its effect may last longer.

Many people assume that a coffee in the evening does not affect sleep. In fact, however, it is not only falling asleep that matters. Even if you feel tired and can fall asleep without any problems, caffeine may still be in the body. This can impair sleep quality by shortening deep sleep phases and reducing night-time recovery. As a result, sleep often becomes lighter and less restful.

An example:

If you drink a coffee with around 150 mg caffeine at 5 p.m. and your half-life is around 4 hours, there will still be around 75 mg caffeine in your body at 9 p.m. – roughly the amount of half to a whole cup of coffee.

As a rough guide:

• Sensitive people: last coffee around 6–8 hours before going to bed
• Average caffeine tolerance: around 4–6 hours before

If you often have trouble falling asleep or find it difficult to wind down in the evening, you should plan your last caffeinated drink earlier in the day and test individually how your own body reacts.

Even if you train in the evening and drink a pre-workout booster before training, you should take the caffeine content into account. Depending on the timing, it can still influence your sleep quality hours later.

For example, if you go to sleep at around 10 p.m. and are sensitive to caffeine, it makes sense to drink your last cup of coffee no later than between 2 and 4 p.m.

If you love the taste of coffee but want to avoid caffeine in the evening, our decaffeinated protein coffee can be a good alternative.

https://de.statista.com/themen/171/kaffee/#topicOverview

https://www.efsa.europa.eu/sites/default/files/corporate_publications/files/efsaexplainscaffeine150527de.pdf

Reichert, C. F., Deboer, T., & Landolt, H.-P. (2022). Adenosine, caffeine, and sleep–wake regulation: state of the science and perspectives. Journal of Sleep Research, 31(4), e13597.

Drake, C., Roehrs, T., Shambroom, J. et al. (2013). Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed. J Clin Sleep Med 9, 1195–1200.