Homegrounds is reader-supported. When you buy via the links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Home » How Long Does Caffeine Stay In Your System? (The Whole Truth)

How Long Does Caffeine Stay In Your System? (The Whole Truth)

Coffee, espresso, and cafe drinks like mochas are delicious. In fact, they’re so delicious it can be easy to overdo it. Have you ever enjoyed one too many and found yourself with shaky hands or a pounding headache?

You probably wondered: how long does caffeine stay in the body? How soon will this feeling pass? Keep reading for the answer – plus the steps you can take if you’ve had too much.

Caffeine Basics

Caffeine is the world’s most widely consumed drug, loved for the quick boost of energy it delivers. Caffeine occurs naturally in many plants, like coffee, tea, and cacao. And it is added to products like sodas, energy drinks, and exercise fuel.

The Effects of Caffeine on the Body

Caffeine has many positive effects on the body when consumed in appropriate doses. It boosts energy, increases alertness, and improves focus. It also has long-term health benefits, like preventing many common diseases.

Caffeine can have negative consequences if you take too much. The most common symptoms of mild caffeine overdose are insomnia, jitters, anxiety, increased heart rate, and headaches.

How Long Does Coffee Last In The Body?

The effects of caffeine are felt after 15 minutes and peak after about 30 to 60 minutes. 

The half-life of caffeine is 3 to 6 hours, so half the caffeine remains in your system 3 to 6 hours after a cup of coffee or energy drink.

For example, how long does 100mg of caffeine stay in your system? – If you drink a cup of coffee with 100 mg of caffeine at 8 a.m., by noon, about 50 mg remains in your body. By 4 p.m., that’s down to 25 mg. It can take up to 10 hours for your body to fully metabolize caffeine.

How long does caffeine stay in your system

Caffeine affects everybody differently, so take these guidelines with a grain of salt. Your age, gender, body weight, genetics, and caffeine consumption habits all influence how the drug interacts with your body.

Want to know more about how your genetics influence your caffeine tolerance? Check out this fascinating video:

Caffeine And Sleep Disruption

Studies have shown that caffeine consumed up to six hours before bedtime can interfere with sleep quality and duration (1).

Results demonstrated a moderate dose of caffeine at bedtime, 3 hours prior to bedtime, or 6 hours prior to bedtime each have significant effects on sleep disturbance relative to placebo.

If you struggle to sleep, it is best to avoid consuming caffeine or even soda in the afternoon. Consider one of these alternatives instead, and beware that even decaf coffee only needs to be 97% caffeine free.

Can You Flush Caffeine Out Of Your System?

Are you starting to regret that fourth double shot of espresso? Alas, there is no way to flush the caffeine from your system any faster, but you can lessen its effects. Drink lots of water to minimize jitters and headaches caused by dehydration. Take deep breaths to slow your heart rate and reduce anxiety. Head out the door for a jog or another form of exercise to use up that excess energy.

Final Thoughts

How long does coffee last in your system? Probably longer than you think! It can take up to 10 hours to stop feeling the effects of caffeine. So if you’re sensitive to its effects, stay clear of coffee, tea, and sodas for at least six hours before bedtime. And remember to always pair your caffeinated drinks with plenty of water.


A safe dose of caffeine is no more than 400 mg per day for an average adult, as recommended by the FDA. The amount of caffeine per cup of coffee is about 100 mg, so this daily limit is equivalent to four cups.

No, caffeine is not addictive in the same way as heroin or methamphetamines (2). However, it does have addictive properties that can lead to physical dependence. If you drink a lot of coffee, you may find you need to consume more and more to get the same energy boost.

Yes, it is safe to consume caffeine while breastfeeding, according to La Leche League. The baby consumes about 1.5% of the maternal dose. The safe dose is lowered slightly to 200 to 300 mg (two to three cups of coffee) daily.

  1. Drake C; Roehrs T; Shambroom J; Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med 2013;9(11):1195-1200. Retrieved from https://jcsm.aasm.org/doi/10.5664/jcsm.3170#d3e499
  2. Meredith SE, Juliano LM, Hughes JR, Griffiths RR. Caffeine Use Disorder: A Comprehensive Review and Research Agenda. J Caffeine Res. 2013 Sep;3(3):114-130. doi: 10.1089/jcr.2013.0016. PMID: 24761279; PMCID: PMC3777290. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3777290/
Julia Bobak
I love trail running, rock climbing, coffee, food, and my tiny dog — and writing about all of them. I start every morning with a fresh Americano from my home espresso machine, or I don’t start it at all.

Leave a Comment