The main components of green tea are tannin, caffeine, proteins, fat, carbohydrates, fiber, ash and vitamin C.
| Tannin | Caffeine | Proteins | Fat | Carbohydrates | Fiber | Ash | Vitamin C | |
| Matcha | 10.0 | 3.5 | 29.1 | 4.1 | 32.7 | 11.1 | 6.4 | 110 |
| Gyokuro | 10.0 | 3.2 | 30.7 | 5.3 | 28.6 | 10.0 | 7.4 | 60 |
| Sencha | 13.0 | 2.3 | 24.0 | 4.6 | 35.2 | 10.6 | 5.4 | 250 |
| Kamairicha | 13.0 | 2.5 | 24.2 | 3.5 | 35.6 | 10.7 | 5.5 | 200 |
| Bancha (Yanagi) |
11.0 | 2.0 | 19.7 | 4.4 | 33.5 | 19.5 | 5.5 | 150 |
| Hojicha | 9.5 | 1.9 | 18.2 | 4.8 | 39.2 | 18.7 | 5.5 | 44 |
| Oolong tea | 12.5 | 2.4 | 19.4 | 2.8 | 39.8 | 12.4 | 5.3 | 8 |
| Black tea | 20.0 | 2.7 | 20.6 | 2.5 | 32.1 | 10.9 | 5.2 | 0 |
Unit：mg
Tannin is the source of tea’s astringency. It has been shown in many studies that the catechin in tannin fights bacteria and lowers cholesterol.
Caffeine is the source of tea’s bitterness. Although caffeine is a stimulant, its potency in green tea is somewhat offset by the presence of theanine, an amino acid which offers a calming effect.
The proteins in tea are the source of the tea’s flavor. The shade-cultivated leaves of gyokuro and matcha contain relatively high concentrations of proteins.
Small amounts of these components are soluble in hot water.
Green tea, especially sencha, contains a relatively high amount of vitamin C. Readily soluble in hot water, vitamin C is known for building up a resistance to common colds, and for offsetting the effects of alcohol and nicotine.
Theanine is an important amino acid found in green tea. It is responsible for the flavor and aroma of the tea. It also produces a calming effect on the body.
The amount of theanine found in the different types and grades of green tea is shown in the table below.
| Type of tea | Theanine mg/100g |
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| Matcha
Higher-grade Medium-grade Lower-grade |
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| Gyokuro
Higher-grade Medium-grade Lower-grade |
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| Sencha
Premium-grade Higher-grade Medium-grade Lower-grade |
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| Bancha | --- |
