Holiday Scones recipes at Tea Recipes
How long does caffeine stay in your system?
It depends on several things which can include
Up to 99% of natural caffeine is absorbed within 45 minutes.
It passes through the blood brain barrier, placenta, and into breast milk, as well as all body tissues.
Then about 97% of it is metabolized by the liver into more than 25 different chemicals.
Caffeinated chemicals eliminated
Almost all of these chemicals are then eliminated from the body within 24 to 48 hours, but caffeine metabolism is faster if
and it is slower if
Tea and coffee comparison
Both tea caffeine and coffee are metabolized into theophylline but through different pathways.
Approximately 90% of North American and European adults report daily consumption of caffeinated products, with approximately 54% of Americans averaging 3 cups of coffee daily.
Other countries (approximately 5 billion people) use daily green or black tea, which is much lower in caffeine than coffee.
References for How Long Does Caffeine Stay In Your System
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Bergey MR et al: Behavioral and perceived stressor effects on urinary catecholamine excretion in adult Samoans. Am J Hum Biol, Sept-Oct 2011, 693-702.
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Chou T. (1992). Wake up and smell the coffee. Caffeine, coffee and the medical consequences. West. J. Med. 157, 544–553.
Croft M et al: Predicting Drug Candidate Victims of Drug-Drug Interactions, using Microdosing. Clin Pharmacokinet. February 2012.
Del Coso J et al: Caffeine during exercise in the heat: thermoregulation and fluid-electrolyte balance. Med Sci Sports Exerc, January 2009, 164-73.
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Grosso L. M., Bracken M. B. (2005). Caffeine metabolism, genetics and perinatal outcomes: a review of exposure assessment considerations during pregnancy. Ann. Epidemiol. 15, 460–466.
Ito E et al: Theophylline metabolism in higher plants. Biochim Biophys Acta, August 1997, 323-30.
James J: Can Consuming Caffeine While Breastfeeding Harm Your Baby? An Interview with Ruth Lawrence, PhD. Journal of Caffeine Research, December 2011.
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Murray S et al: Effect of cruciferous vegetable consumption on heterocyclic aromatic amine metabolism in man. Carcinogenesis, September 2001, 1413-20.
Nehlig A. (1998). Are we dependent upon coffee and caffeine? A review on human and animal data. Neurosci. Biobehav. Rev. 23, 563–576.
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Vrtic F et al: Interaction of ibuprofen and probenecid with drug metabolizing enzyme phenotyping procedures using caffeine as the probe drug. British Journal Clin Pharmacol, February 2003, 191-8.
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This page last updated by Sharon Jones on March 4, 2013
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