How Long Does Caffeine Stay In Your System? Metabolism And More

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Medical News TodaySubscribeHow long does a cup of coffee stay in the body?

Medically reviewed by Natalie Olsen, R.D., L.D., ACSM EP-C — Written by Jon Johnson — Updated on June 19, 2023

Metabolism
Caffeine sources
Quantities
Breast-feeding
Sleep
Side effects
Withdrawal symptoms
Takeaway

Caffeine acts quickly, and many people notice the effects within minutes. They last until the body fully metabolizes the drug. This duration depends on several factors.

Each person will feel the effects differently, and some may last longer than others. People who are pregnant or have difficulty sleeping should be careful about timing their caffeine intake and may want to avoid it altogether.

How long does it take to metabolize caffeine?

Caffeine in coffee being poured into cup surrounded by coffee beans. — Caffeine may have a greater effect on people who are sensitive to it.

Caffeine has a half-life of about 5 hours.

Someone who consumes 40 milligrams (mg) of caffeine will have 20 mg remaining in their system after 5 hours.

When do effects peak?

Levels of caffeine peak in the blood within about 15–45 minutes of consumption.

They are then quickly metabolized by the liver.

Most people notice the strongest effects during this time, and many report feeling jittery, needing to urinate, and having sudden bursts of energy. These symptoms tend to go away as the caffeine starts to break down.

Can a person build up a tolerance?

As the body becomes resistant to the drug, people who regularly consume caffeine may barely notice its effects.

However, for someone who is very sensitive to caffeine, effects may persist for hours or until the next day.

How long do effects last?

There is no set time limit. The duration of the drug’s effects depend upon the dosage and on personal factors, including age, body weight, and how sensitive a person is to caffeine.

Foods and drinks that contain caffeine

Caffeine is usually found in beverages, including:

coffee and drinks such as espressos, lattes, and cappuccinos
black, green, and white tea
yerba maté
many soft drinks
energy drinks

Even decaffeinated coffee contains some caffeine, and people who are very sensitive to caffeine should avoid it.

Caffeine can also be found in foods, such as:

chocolate and products containing it, such as hot cocoa
coffee or mocha ice creams
guarana seeds and beverages
some protein and energy bars
pre-workout drinks and powders

Caffeine is also a common ingredient in weight loss pills and over-the-counter headache medicines, including Excedrin.

How much caffeine is in each product?

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Energy drinks have higher levels of caffeine than tea or coffee.

The amount of caffeine in products like coffee and tea varies, but the American Academy of Sleep Medicine has listed the following estimates:

8 ounces (oz) of brewed coffee – 95 mg
1 oz of espresso – 64 mg
8 oz of brewed tea – 47 mg
16-oz average energy drink – 158 mg
12-oz average caffeinated soda – 45 mg
1.55-oz milk chocolate candy bar – 9 mg

Drugs that contain caffeine will display exact amounts on their labels.

Caffeine and breast-feeding

People are usually warned not to consume caffeine while pregnant, as it can pose risks to the mother and child. While these risks diminish after birth, caffeine can affect a baby who is breast-fed.

Small amounts of caffeine can be transferred through breast milk, so anyone who is nursing should limit their caffeine intake before feedings. Most babies older than 3 months can tolerate these relatively small amounts. One study found that regular caffeine consumption by nursing women had little or no consequences on sleep patterns of babies and children aged over 3 months.

However, large amounts of caffeine can make babies fussy and irritable. It can also lead to trouble developing regular sleep patterns and other negative effects.

A doctor can provide specific recommendations, but there should generally be a 1–2-hour gap between caffeine consumption and nursing.

How does caffeine affect sleep?

The overall effects of caffeine can last throughout the day. The drug can linger in the body and may have subtle consequences, even after the noticeable effects have worn off.

Caffeine can lead to sleep of a lesser quality and even disrupt sleep patterns, depending on a person’s sensitivity and how much they have consumed.

Most adults can safely consume 200–300 mg per day, and exceeding this amount can lead to sleep issues.

What to do when too much caffeine disrupts sleep?

If someone suspects that their caffeine intake is causing sleepless nights, they should lower their consumption until they determine the right limit.

It may also help to practice relaxation techniques before bed, such as gentle yoga or breathing exercises.

Caffeine can be a helpful stimulant, but excessive consumption can mask underlying sleep disorders. People who need coffee or tea to wake up every morning may be unwittingly compensating for sleep issues.

Develop a regular sleep schedule by going to bed and waking up at around the same times each day. This can help the body to regulate itself, and reduce the need for stimulants like caffeine.

Side effects of caffeine

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Caffeine may cause diarrhea or an upset stomach.

People will quickly realize when they have had too much caffeine. Be aware of the following symptoms:

nervousness
a stomachache
diarrhea
a rapid or irregular heartbeat
an increased rate of breathing
insomnia
feeling fidgety or restless
sweating
irritability
anxiety attacks

People with kidney or liver problems may find their health gets worse when they have caffeine.

In some cases, caffeine can make fatigue worse. If someone is exhausted, they may benefit more from napping or practicing a relaxation technique before resuming activity.

Like other drugs, it is possible to become dependent on caffeine, and going without it can lead to symptoms of withdrawal.

Symptoms of caffeine withdrawal

People who stop consuming caffeine often complain of withdrawal. Symptoms include:

general fatigue
crankiness or irritability
muscle pain
nausea or an upset stomach
a lack of focus
headaches or migraines

These symptoms may resolve when a person consumes caffeine again. If a person is determined to stop, withdrawal symptoms often pass within a few days.

When a person who regularly consumed high amounts of caffeine stops suddenly, they may experience more severe withdrawal symptoms.

Rather than quitting abruptly, it may be better to gradually reduce caffeine intake until it can be eliminated without symptoms.

Takeaway

The effects of caffeine typically last for a few hours, unless someone has consumed a high amount or is especially sensitive to the drug.

Caffeine lingers in the body and may disrupt sleep patterns, even after noticeable effects have worn off.

While it is generally considered safe to consume caffeine while breast-feeding, it may be a good idea to cut off consumption 1–2 hours before a feed.

Anyone who regularly has trouble sleeping or waking up should discuss underlying sleep disorders with a doctor.

It may be a good idea to explore natural ways to increase energy levels.

Alcohol / Addiction / Illegal Drugs
GastroIntestinal / Gastroenterology
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Sleep / Sleep Disorders / Insomnia

How we reviewed this article:

SourcesMedical News Today has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Heffron, T. M. (2018, January 29). Sleep and caffeinehttp://www.sleepeducation.org/news/2013/08/01/sleep-and-caffeine
Santos, I. S., Matijasevich, A., & Domingues, M. R. (2012, May). Maternal caffeine consumption and infant nighttime waking: Prospective cohort study. Pediatrics, 129(5), 860–868https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566755/
Sepkowitz, K. A. (2012, December 19). Energy drinks and caffeine-related adverse effects. JAMA, 309(3), 243–244https://pdfs.semanticscholar.org/44a3/3f560c4b83c081512155ea8e9cfe44f81009.pdf
Thorlton, J., Ahmed, A., & Colby, D. A. (2016, May–June). Energy drinks: Implications for the breastfeeding mother [Abstract]. MCN: The American Journal of Maternal/Child Nursing, 41(3), 179–185https://journals.lww.com/mcnjournal/Abstract/2016/05000/Energy_Drinks__Implications_for_the_Breastfeeding.9.aspx

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Medically reviewed by Natalie Olsen, R.D., L.D., ACSM EP-C — Written by Jon Johnson — Updated on June 19, 2023

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Tag » How Long Does 200mg Of Caffeine Last

How Long Does Caffeine Stay In Your System? Metabolism And More

How long does it take to metabolize caffeine?

Foods and drinks that contain caffeine

How much caffeine is in each product?

Caffeine and breast-feeding

How does caffeine affect sleep?

What to do when too much caffeine disrupts sleep?

Side effects of caffeine

Symptoms of caffeine withdrawal

Takeaway

How we reviewed this article:

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