50 Fun Facts About Caffeine

Caffeine keeps you awake mainly by blocking the receptors of which sleep-promoting molecule?

The molecule builds up in the brain the longer you stay awake; caffeine has a similar shape and sits in its receptors without switching them on.

To which chemical class of stimulants does caffeine belong?

Its cousins theophylline and theobromine, found in tea and chocolate, are also methylxanthines and are used to treat asthma.

Caffeine is chemically related to which components of DNA and RNA?

It is a purine alkaloid, a bitter white crystalline solid.

What title does caffeine hold among the world's psychoactive substances?

Global consumption is estimated at 120,000 tonnes a year, and unlike almost every other psychoactive drug it is legal nearly everywhere.

Why do plants such as coffee and tea make caffeine in the first place?

It can paralyse and kill insects, and it leaches into the soil to stop rival seeds germinating near coffee seedlings.

Caffeine has been found to enhance the reward memory of which animals, encouraging them to return to a plant?

For dogs, cats, birds and spiders, by contrast, it is toxic, because they metabolise it poorly.

Roughly how many plant species are known to contain caffeine?

Coffee seeds and tea leaves are the familiar ones, but there are others from South America and West Africa.

Which German chemist first isolated caffeine, in 1819, calling it 'Kaffebase'?

French chemists isolated it independently two years later, and Berzelius eventually acknowledged the German's priority.

Which famous writer handed a young chemist a box of coffee beans to analyse in 1819, leading to the discovery of caffeine?

The chemist had impressed him by dilating a cat's pupils with belladonna extract; a few months later he had identified caffeine.

Which future 1902 Nobel laureate first achieved a total synthesis of caffeine in 1895?

He worked out its structural formula two years later; industrial caffeine has since been synthesised from urea and chloroacetic acid.

The word 'caffeine' first appeared in print in which language?

Pelletier used it in an 1821 article, from café; the 'théine' isolated from tea in 1827 turned out in 1838 to be the same compound.

In 1911 the US government seized 40 barrels and 20 kegs of which product, alleging its caffeine was 'injurious to health'?

The Supreme Court case was literally titled United States v. Forty Barrels and Twenty Kegs of Coca-Cola, and the company won.

Which English king tried to ban coffee in 1676?

Frederick II of Prussia banned it in 1777, and Sweden outlawed it several times between 1756 and 1823.

How much caffeine per day does the European Food Safety Authority say raises no safety concerns for a healthy adult?

That is roughly 5.7 mg per kilo of body weight; Health Canada uses the same 400 mg ceiling.

Roughly how much caffeine is in a 6-ounce cup of coffee?

It depends on the bean, the roast and whether it is drip, percolated or espresso.

About how many ordinary cups of coffee would it take to reach a lethal dose of caffeine?

The fatal dose is around 150-200 mg per kilo of body weight, over 10 grams for an adult.

What quantity of pure powdered caffeine, sold as a supplement, can be lethal?

Several deaths have been linked to the powder, which is unregulated as a dietary supplement in the US.

What is the typical half-life of caffeine in a healthy adult?

In newborns it can be 80 hours or more, and it roughly doubles in women taking oral contraceptives.

How does smoking tobacco affect the body's handling of caffeine?

Hydrocarbons in smoke induce the liver enzyme CYP1A2, which is why regular smokers tend to drink more coffee.

Caffeine citrate is on the WHO's list of essential medicines for treating which condition?

It also treats bronchopulmonary dysplasia in premature babies and can improve their weight gain and cut cerebral palsy risk.

Regular caffeine consumption may reduce the risk of which neurological condition?

It may also slow the condition's progression; the evidence for a protective effect against Alzheimer's is inconclusive.

Adding 100-130 mg of caffeine to common painkillers such as paracetamol does what?

Caffeine has been found to raise the potency of some over-the-counter analgesics by about 40%.

Which of these was caffeine formerly used as a second-line treatment for?

It works better than placebo but worse than methylphenidate; people with the condition drink more caffeine, perhaps self-medicating.

Which amino acid found in tea has synergistic alerting effects when taken with caffeine?

A 2014 meta-analysis found the pair improved alertness, attention and task switching, mostly within the first hour.

Roughly what dose of caffeine per kilogram improves sprint, cycling and endurance performance?

It also raises basal metabolic rate and fat oxidation, and lowers perceived exertion during steady exercise.

Daily consumption of 1 to 1.5 grams of caffeine is associated with which condition?

It combines dependency with nervousness, irritability, insomnia, headaches and palpitations.

Which of these is a recognised symptom of caffeine withdrawal?

Sleepiness, irritability, flu-like symptoms and trouble concentrating are the others; symptoms rarely last more than a day.

As of 2021, how does the World Health Organization classify caffeine?

The DSM-5 lists 'caffeine-use disorder' only as a condition for further study, though ICD-11 recognises caffeine dependence.

Which US regulator classifies caffeine as 'generally recognized as safe'?

It considers drinks with under 0.02% caffeine safe, while pure caffeine powder remains unregulated as a supplement.

Which merchant invented the first commercially successful decaffeination process in 1903, after seawater soaked a shipment of beans?

His original process used benzene, now known to be a carcinogen, so other solvents replaced it.

Which country, the birthplace of decaf, hosts the world's largest decaffeination plant?

More than half the decaf sold in the US travels from the tropics to Germany to have its caffeine removed first.

The Swiss Water decaffeination process is distinctive because it avoids what?

Developed in Switzerland in 1933, it relies on charcoal filters; supercritical CO2 is a separate solvent-free method.

Under US standards, what share of the caffeine must be removed for coffee to be sold as decaf?

One study still found about 10 mg of caffeine per cup of decaf, against roughly 85 mg for regular coffee.

Theobromine, a relative of caffeine and one of its metabolites, is the principal alkaloid in which food?

The Maya drank a bitter, spicy chocolate called xocolatl by 600 BCE, and its fatigue-fighting reputation probably came from theobromine.

Cola soft drinks were originally flavoured with, and got their caffeine from, which ingredient?

The nut is still chewed in West Africa to restore vitality; a modern cola carries up to 55 mg of caffeine per 12-ounce serving.

The South American drink maté is sipped through a filtering straw called what?

The gourd holds leaves of the yerba mate holly, topped up with hot but not boiling water.

Which pale Japanese green tea contains far more caffeine than many darker teas?

Colour is a poor guide to caffeine in tea, which also carries small amounts of theobromine and theophylline.

Energy drinks such as Red Bull start at roughly how much caffeine per serving?

Ordinary soft drinks range from 0 to 55 mg per 12 ounces; despite the hype, energy drinks add little to total caffeine intake overall.

Red Bull was derived from which Thai drink, popular with truck drivers?

The name means 'red gaur'; Chaleo Yoovidhya launched it in 1976 and his family still controls 51% of Red Bull GmbH.

In which country is Red Bull GmbH headquartered?

Its home is Fuschl am See, a village of about 1,500 people near Salzburg; Dietrich Mateschitz first sold the drink at Austrian ski resorts.

According to The New York Times, 'the energy drink as we know it' was born in which country in 1962?

Taisho Pharmaceuticals' Lipovitan was the model; America's caffeine-and-B-vitamin Dr. Enuf had appeared in 1949.

Which company launched Monster Energy in 2002 and later renamed itself after it?

By 2020 Monster held 39% of the global energy-drink market against Red Bull's 43%.

Which 2-ounce product, launched in 2004, created the 'shot' offshoot of the caffeinated-drink category?

Red Bull followed with its own 2-ounce Energy Shot in 2009.

Besides caffeine, which amino acid is the classic ingredient of energy drinks?

There is no reliable evidence that it, guarana or added B vitamins provide any benefit beyond the caffeine.

What did the FDA's investigation announcement in 2013 prompt the makers of Alert Energy Caffeine Gum to do?

A year earlier the agency had warned a company selling a caffeine inhaler that resembled an e-cigarette.

The antidepressant fluvoxamine can stretch caffeine's half-life to how long?

It cuts caffeine clearance by more than 90%, so a morning coffee can still be circulating two days later.

How many symptoms from the DSM-5 list are needed to diagnose caffeine intoxication after a big dose?

The list runs from restlessness and flushed face to muscle twitching, rambling speech and rapid heartbeat.

How much caffeine per day do the UK Food Standards Agency and ACOG consider acceptable in pregnancy?

Caffeine metabolism slows sharply in the third trimester, when the half-life can stretch to 15 hours.

How many tonnes of coffee beans were consumed globally in 2020?

Coffee, tea and soft drinks remain the three main sources of the world's caffeine.

Health Canada's caffeine limit for children aged 12 and under is set at what?

The American Academy of Pediatrics goes further and says energy drinks are not appropriate for anyone under 18.