Green Tea vs Black Tea: Caffeine, Catechins and Which to Choose

Green tea and black tea come from the same plant; the difference is processing. Green tea is made so the leaf's catechins are not oxidized, while black tea is oxidized on purpose, turning most catechins into theaflavins and thearubigins (Graham, 1992). Black tea usually has more caffeine, about 47 mg per 8 oz against about 28 mg for green tea (USDA FoodData Central; USDA FoodData Central), though individual teas overlap (Chin et al., 2008). Large reviews link tea drinking in general with more benefit than harm (Yi et al., 2019). This guide compares caffeine, compounds, research and how to choose.

It is educational, not medical advice.

Key Takeaways

• Same plant: green tea is not oxidized; black tea is oxidized, and oolong sits in between (Graham, 1992).
• Compounds: green tea keeps its catechins, such as EGCG; in black tea they become theaflavins and thearubigins (Graham, 1992).
• Caffeine: about 28 mg per 8 oz for green tea and about 47 mg for black tea (USDA FoodData Central; USDA FoodData Central); 37 mg and 71 mg per 12 oz (FDA).
• Overlap: in lab tests, white, green and black teas all held 14 to 61 mg per serving, and steep time mattered (Chin et al., 2008).
• Research: an umbrella review found the largest benefit links for tea at two to three cups a day (Yi et al., 2019).

Green Tea vs Black Tea at a Glance

	Green tea	Black tea
Processing	Not oxidized	Oxidized
Main polyphenols	Catechins such as EGCG	Theaflavins and thearubigins
Caffeine per 8 oz (USDA)	about 28 mg	about 47 mg
Caffeine per 12 oz (FDA)	37 mg	71 mg
L-theanine	Yes	Yes

Processing facts are from a review of tea chemistry (Graham, 1992). Caffeine per 8 oz is calculated from USDA values of 12 mg per 100 g for brewed green tea (USDA FoodData Central) and 20 mg per 100 g for brewed black tea (USDA FoodData Central); the 12 oz figures are FDA typical amounts (FDA).

How Processing Makes Them Different

Fresh tea leaves are unusually rich in catechins, which can make up to 30% of the dry leaf weight. Green tea is prepared in a way that stops these catechins from being oxidized. For black tea, the leaf is broken up so an enzyme can oxidize the catechins, and the products join into theaflavins, thearubigins and related compounds that give black tea its color and taste. Oolong tea is partly oxidized (Graham, 1992).

Caffeine: Which Has More?

On average, black tea: about 47 mg per 8 oz against about 28 mg for green tea (USDA FoodData Central; USDA FoodData Central). In practice the brand, leaf and brewing also matter. When researchers brewed 20 tea products, white, green and black teas all fell between 14 and 61 mg per serving with no clear trend by type of tea, and steep time changed the caffeine (Chin et al., 2008). Both have much less than brewed coffee, about 95 mg per 8 oz (USDA FoodData Central). Our guide to caffeine in black tea covers cup sizes and brewing.

Chai is spiced black tea; our guide to how much caffeine is in chai tea covers chai and chai lattes.

Oolong, the partly oxidized tea between the two, usually lands in the middle for caffeine too; see how much caffeine is in oolong tea.

White tea comes from the same plant too; our guide to how much caffeine is in white tea compares it with both.

What Research Shows for Tea

An umbrella review of 96 meta-analyses of observational studies found that tea drinking showed greater benefit than harm, with the largest risk reductions at two to three cups a day, including lower risk of death from any cause. It flagged one harm: drinking tea hotter than about 55 to 60 degrees Celsius was associated with cancers of the esophagus and stomach, so let your cup cool a little (Yi et al., 2019). These studies mostly look at tea in general rather than comparing green and black directly, and observational research shows links rather than cause and effect.

For the green tea catechin EGCG, including concentrated extracts and their safety, see our guide to green tea extract and EGCG.

L-Theanine in Both Teas

Both green and black tea naturally contain L-theanine, an amino acid found in the tea plant. In a placebo-controlled study, 50 mg of caffeine with 100 mg of L-theanine improved speed and accuracy on an attention switching task and reduced distraction in a memory task (Owen et al., 2008). That pairing is part of why tea often feels gentler than coffee. Read more in L-theanine and caffeine and L-theanine benefits.

Green and black tea are both used to brew kombucha, which keeps some of their caffeine; see how much caffeine is in kombucha.

Which Should You Choose?

• Choose green tea: if you want less caffeine on average and the catechins green tea keeps (Graham, 1992).
• Choose black tea: if you want a stronger cup that sits closer to coffee, at about half its caffeine (USDA FoodData Central; USDA FoodData Central).
• Drink both: the tea review found the largest benefit links at two to three cups a day of tea in general (Yi et al., 2019).
• Control the caffeine: shorter steeping makes a lighter cup of either (Chin et al., 2008).

Comparing tea with coffee instead? See tea vs coffee and matcha vs coffee.

Where Our Products Fit

Theanine Nasal Spray gives 36 mg of L-theanine per serving and is caffeine-free, for anyone who likes the idea of tea's theanine alongside their usual drink. The Energy Stack combines NAD+ Nasal Spray, Forage and Methyl B-12 Nasal Spray in one daily energy routine. Read more on our L-theanine ingredient page and the Non-Stimulant Energy and Focus hub.

Frequently Asked Questions

Is green tea healthier than black tea?

Neither clearly wins. Green tea keeps more catechins and black tea has theaflavins and thearubigins (Graham, 1992); the large tea review looked mostly at tea in general (Yi et al., 2019).

Which has more caffeine, green tea or black tea?

Black tea on average: about 47 mg against about 28 mg per 8 oz (USDA FoodData Central; USDA FoodData Central), though teas overlap (Chin et al., 2008).

Are green tea and black tea from the same plant?

Yes. The difference is processing: green tea is not oxidized and black tea is (Graham, 1992).

Does black tea have polyphenols?

Yes. Its catechins are turned into other polyphenols, theaflavins and thearubigins, during processing (Graham, 1992).

Is green tea or black tea better for focus?

Both carry caffeine and L-theanine; black tea has more caffeine on average (USDA FoodData Central; USDA FoodData Central). The caffeine and L-theanine pairing improved attention switching in a study (Owen et al., 2008).

Is oolong tea green or black?

Neither. Oolong is partly oxidized, between green and black tea (Graham, 1992).

Can I drink green tea and black tea on the same day?

Yes, as long as your total caffeine suits you; the FDA cites 400 mg a day for most adults (FDA).

Which tea is better in the evening?

Green tea has less caffeine on average (USDA FoodData Central), but herbal teas, with no caffeine detected in lab tests (Chin et al., 2008), are the easiest evening choice.

Sources

1. Graham HN. Green tea composition, consumption, and polyphenol chemistry. Prev Med. 1992. PubMed 1614995
2. Chin JM, Merves ML, Goldberger BA, Sampson-Cone A, Cone EJ. Caffeine content of brewed teas. J Anal Toxicol. 2008. PubMed 19007524
3. Yi M, Wu X, Zhuang W, et al. Tea consumption and health outcomes: umbrella review of meta-analyses of observational studies in humans. Mol Nutr Food Res. 2019. PubMed 31216091
4. Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. 2008. PubMed 18681988
5. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? FDA
6. U.S. Department of Agriculture. FoodData Central: Beverages, tea, green, brewed, regular (FDC 171917); Beverages, tea, black, brewed, prepared with tap water (FDC 173227); Beverages, coffee, brewed, prepared with tap water (FDC 171890). FoodData Central

Our products are not intended to diagnose, treat, cure or prevent any disease. This article is for education only and is not medical advice.