Theine and caffeine: one molecule, two names

October 26, 2026

Short answer: there is no difference. Theine and caffeine are one and the same molecule, 1,3,7-trimethylxanthine, with the formula C8H10N4O2. What we call theine is simply caffeine when it comes from a tea leaf. The two names do not describe two substances, they describe two discoveries.

So what changes from a cup of tea to a cup of coffee is not the molecule. It is the amount, and that depends far more on how you brew than most people think.

Two names, two discoveries, one molecule

The story begins with coffee. In 1819, the German chemist Friedlieb Ferdinand Runge isolated relatively pure caffeine from coffee beans for the first time, at Goethe's request.

Eight years later, in 1827, a researcher named Oudry extracted a crystalline substance from tea leaves and named it theine. Nobody yet knew it was the same compound: each plant seemed to have its own active principle, and each one got its own name.

It was not until 1838 that two chemists, the Dutchman Gerardus Johannes Mulder and, independently, Carl Jobst, showed that Oudry's theine and Runge's caffeine were identical. At the end of the 19th century, Emil Fischer worked out its structure and then synthesised it; his work on this family of molecules, the purines, earned him the Nobel Prize in Chemistry in 1902.

Since then, chemists have spoken only of caffeine. The word theine has survived in everyday language and on packaging, and it is what keeps alive the idea of two different substances. The same molecule is also found in other plants: cocoa, maté, guarana and kola nut.

How much in a cup?

The figures most often quoted in Europe come from the European Food Safety Authority (EFSA), in its 2015 opinion on caffeine:

a cup of filter coffee (200 ml): about 90 mg;
an espresso (60 ml): about 80 mg;
a cup of tea (220 ml): about 50 mg;
a can of cola (355 ml): about 40 mg;
a bar of dark chocolate (50 g): about 25 mg.

These are averages, not guarantees: two cups of tea brewed differently can stray well away from this figure.

The surprising detail: weight for weight, tea leaves contain more caffeine than coffee beans. Caffeine makes up 1 to 4% of the dry weight of tea leaves, roughly half that in coffee. If a cup of tea ends up with less, it is because very few leaves are used: our product pages suggest about 3 g for a 250 ml cup, whereas a cup of coffee needs noticeably more grounds. And not all the caffeine in the leaf passes into the water, which brings us to brewing.

Temperature and time: what decides the amount

Caffeine dissolves better the hotter the water. The reference data speak for themselves: one gram of caffeine dissolves in about 46 ml of water at room temperature, in 5.5 ml of water at 80 °C, and in 1.5 ml of boiling water.

Time matters just as much. A study published in 2025 in the journal Foods by a team from Gazi University in Ankara measured the caffeine in six families of tea brewed at 2 g per 200 ml. At 100 °C, the green tea in the study gave about 15 mg after 2 minutes, 25 mg after 5 minutes and 27 mg after 10 minutes. The first few minutes do most of the work, then the curve flattens out.

Two practical consequences:

A quick rinse does not remove the caffeine. We recommend rinsing the leaves of the Pu Erh d'origine for about ten seconds before brewing, but that is for the flavour: if two minutes at 100 °C extract only part of the caffeine, ten seconds take out even less.
A second infusion still contains some, since the first did not extract it all. Each steep simply draws on what is left in the leaf.

Green, black, pu erh: colour is not the whole story

You often read that black tea contains more theine than green tea. In the study mentioned above, brewed in exactly the same way (2 g, 200 ml, 100 °C, 5 minutes), the green tea and the black tea gave very similar values, around 25 mg and 23 mg, and the pu erh about 28 mg. The authors note that caffeine is a stable component, little affected by the oxidation or fermentation of the leaves, the very steps that set apart green tea, black tea and pu erh.

What widens the gap in real life is the brewing recommended for each family. Compare our own product pages:

Équinoxe green tea, on a Sencha base, is steeped at 75 to 80 °C for 2 to 3 minutes;
Âme de Sri Lanka black tea, on a Ceylon OP base, is steeped at 100 °C for 3 to 5 minutes;
Pu Erh d'origine is steeped at 100 °C for 4 to 5 minutes.

Hotter water and a longer infusion extract more. At the same amount of leaf, a cup of black tea brewed according to its page therefore has every reason to come out stronger than a cup of green tea brewed according to its own: it is the brewing that widens the gap, more than the colour of the leaf. If you want to know what is in your cup, look at the thermometer and the timer first.

Rooibos and fruit infusions: no tea leaf, no theine

In tea, the caffeine comes from the leaf of the tea plant, Camellia sinensis. A drink that contains no tea leaves therefore has no theine, whatever the name on the label.

That is the case with rooibos, Aspalathus linearis, a South African shrub of the Fabaceae family that does not produce caffeine; we have devoted a whole article to it. Nainfusion rooibos is theine-free. A chemist's footnote, since that is the subject of this article: its blend also contains crushed cocoa beans, and cocoa naturally contains a little caffeine, the same molecule. That is the same reason a bar of dark chocolate provides some, as the list above shows.

It is also the case with fruit and flower infusions. Chant des Sirènes infusion combines apple, hibiscus, rosehip, strawberry, rose and vanilla, with no tea leaves at all: it is naturally theine-free.

Frequently asked questions

Is theine a different kind of caffeine?
No. It is exactly the same molecule, shown to be identical since 1838. A cup of tea of course contains other compounds than a cup of coffee, but the caffeine itself does not change depending on the plant it comes from.

How much theine is in a cup of tea?
EFSA gives an order of magnitude of about 50 mg for a 220 ml cup, against about 90 mg for a 200 ml filter coffee. The real amount depends on the tea itself, but also very much on the amount of leaf, the water temperature and the infusion time.

Does green tea contain less theine than black tea?
Brewed the same way, the leaves give similar amounts. Green tea is generally steeped cooler and for less time, which explains why a cup of green tea often contains less.

Does a second infusion still contain theine?
Yes, since the first infusion does not extract everything. It generally contains less, since it draws on what is left in the leaf.

Does rooibos contain theine?
No. Rooibos is not a tea but a South African shrub that does not produce caffeine. Just watch out for blends that add tea, maté or cocoa.

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