Oolong Tea: Caffeine Levels Explained

A 240 ml cup of oolong tea has 37 mg of caffeine.

• One 240 ml cup of oolong tea contains 37 mg of caffeine (≈15.4 mg/100 ml).
• Oolong has about 10 mg less caffeine per cup than typical black tea (47 mg/240 ml) and 9 mg more than green tea (28 mg/240 ml).
• Population-average caffeine half-life is 5.7 hours; from 37 mg, ~18.5 mg remains after 5.7 hours and ~8.5 mg after 12 hours.
• FDA daily limit for most healthy adults is 400 mg; pregnancy guidance suggests ~200 mg/day, and the American Academy of Pediatrics discourages routine caffeine for adolescents.

Does oolong tea contain caffeine?

Yes. Oolong is a true tea made from Camellia sinensis leaves and therefore contains caffeine. The dataset value used here represents a typical prepared cup: 240 ml of oolong tea has 37 mg of caffeine (15.4 mg per 100 ml). That places oolong between green and black tea in typical caffeine content.

Caffeine levels in different oolong varieties

There is no single fixed number for every oolong. The 37 mg per 240 ml value is an average for a standard cup. Less-oxidized, lighter oolongs (closer to green tea) and shorter steeps produce less caffeine per cup; darker, more heavily processed oolongs and stronger brews will yield more. Commercial bottled oolongs and tea bags can also vary.

Practical serving examples

Drink	Serving (ml)	Caffeine (mg)	mg / 100 ml (if available)
Oolong tea	240 ml	37 mg	15.4 mg/100 ml
Black tea	240 ml	47 mg	19.6 mg/100 ml
Green tea	240 ml	28 mg	11.7 mg/100 ml
White tea	240 ml	16 mg	6.7 mg/100 ml
Matcha (1 tsp)	240 ml	70 mg	—
Drip coffee	240 ml	96 mg	40 mg/100 ml
Cold brew	240 ml	200 mg	83.3 mg/100 ml
Espresso (single)	30 ml	63 mg	—
Red Bull (250 ml)	250 ml	80 mg	32 mg/100 ml

How oolong compares to other teas and coffee

Using the dataset values: a standard oolong cup (37 mg) contains about 39% of the caffeine in a 240 ml cup of drip coffee (96 mg) and roughly half the caffeine of matcha (70 mg per 240 ml). Compared with black tea (47 mg) it’s modestly lower, and notably higher than white tea (16 mg) and herbal infusions (0 mg).

Factors that change oolong's caffeine content

Caffeine per cup depends on leaf mass, leaf particle size, water temperature, steep time and whether you consume infused leaves (as with matcha). Higher leaf-to-water ratios and longer steeps extract more caffeine. Commercial lab values (like those in USDA FoodData Central) represent typical home preparations; individual brews can differ substantially.

How long oolong caffeine lasts in your body

Pharmacokinetically, caffeine follows exponential elimination. The population-average half-life is about 5.7 hours; after each 5.7-hour interval the caffeine quantity roughly halves. Here are approximate remaining amounts from a single 37 mg cup.

Time after drinking	% remaining (approx)	mg remaining from 37 mg
0 hours	100%	37.0 mg
3 hours	~69%	25.5 mg
5.7 hours (half-life)	50%	18.5 mg
6 hours	~48%	17.8 mg
9 hours	~33%	12.2 mg
12 hours	~23%	8.5 mg

Individual half-life varies with age, pregnancy, liver function, smoking (which speeds clearance), and some medications. Sources for population guidance include FDA and peer-reviewed pharmacology summaries; USDA FoodData Central is the reference for beverage nutrient values.

Health considerations and safe limits

For most healthy adults the U.S. FDA notes 400 mg/day as a non-harmful upper bound; European Food Safety Authority and Mayo Clinic offer similar guidance. For pregnant people, many authorities recommend keeping caffeine near or below 200 mg/day. The American Academy of Pediatrics discourages routine caffeine use in adolescents. If you have anxiety, certain heart conditions, or take interacting medications, discuss intake with your clinician.

Because oolong is relatively low in caffeine versus coffee and many energy drinks, it is a practical choice when you want a milder stimulant effect. Track cumulative daily intake using a tool like CoffeeLog to stay within recommended limits, especially if you also drink coffee, matcha, or energy drinks.

Practical tips

• Shorten steep time or reduce leaf mass to lower caffeine in a cup.
• Choose white tea or herbal infusions if you want essentially zero caffeine.
• Avoid late-afternoon oolong if you are sensitive to sleep disruption; even 8–12 mg of remaining caffeine can affect sleep in sensitive people.

This page summarizes typical values; for exact labeling consult product-specific nutrition data or USDA FoodData Central. If you have medical concerns, consult a healthcare professional before changing caffeine-related habits.