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Limited evidenceWeight management

Oolong Tea Extract

Semi-fermented tea whose catechins and caffeine raise fat oxidation slightly in small metabolic studies. No trial has shown meaningful weight loss from the extract.

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What the science says

  • Small rise in fat oxidation Moderate evidence

    A metabolic chamber study in 12 men found oolong tea increased energy expenditure by about 3% and fat oxidation by roughly 12% versus water. A 2020 randomized crossover trial confirmed higher fat oxidation after two weeks of intake, without any change in total energy expenditure.

  • Weight loss not demonstrated Limited evidence

    The metabolic effects are short-term markers, not outcomes. No adequately sized randomized trial has shown that oolong tea extract produces clinically relevant weight or fat mass loss.

  • Increased fecal fat excretion Limited evidence

    A controlled feeding study found polyphenol-enriched oolong tea roughly doubled fecal lipid excretion in healthy adults. The absolute amount of fat lost this way is small and was not linked to body weight change.

Dosage & safety

Studied doseTrials used 4 cups of brewed tea per day or extracts supplying roughly 300–400 mg of tea polyphenols. Typical capsules provide 250–500 mg of extract once or twice daily.
SafetyContains caffeine, so it can cause insomnia and palpitations. Concentrated tea catechin extracts have been linked to rare cases of liver injury; take with food and avoid high doses. Tea polyphenols reduce non-heme iron absorption, which matters for people with low iron.

How to take it

TimingTake it in the morning or early afternoon — the caffeine content will disturb sleep if taken late.
With food?Take concentrated extracts with food, which lowers the rare risk of liver injury seen with tea catechin concentrates.
Worth knowingBrewed tea has a far better safety record than concentrated capsules for the same polyphenols.

Interactions

With medications

  • stimulant medication and high caffeine intake

    Additive insomnia, palpitations and raised blood pressure from the caffeine content. Count it towards your daily caffeine total

  • fluvoxamine and ciprofloxacin

    Both block CYP1A2 and slow caffeine clearance, so the same caffeine dose hits harder and lasts longer. Reduce your caffeine intake while taking these drugs

With other supplements

  • iron supplements

    Tea polyphenols bind non-heme iron and substantially reduce its absorption. Separate by at least 2 hours

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does oolong tea extract help you lose weight?

No trial has shown meaningful weight loss from oolong tea extract, so the evidence for weight loss is limited. It raises fat oxidation slightly in small metabolic studies (moderate evidence), but those are short-term markers, not outcomes.

How much does oolong tea boost metabolism?

In a metabolic chamber study of 12 men, oolong tea raised energy expenditure by about 3% and fat oxidation by roughly 12% versus water; a later trial found higher fat oxidation without any change in total energy expenditure.

How much oolong tea extract per day?

Trials used 4 cups of brewed tea per day or extracts supplying roughly 300–400 mg of tea polyphenols. Take oolong tea extract with food, in the morning or early afternoon, because of its caffeine.

Is oolong tea extract safe for the liver?

Concentrated tea catechin extracts like oolong tea extract have been linked to rare liver injury, so take them with food and avoid high doses; brewed tea has a far better safety record. Separate it from iron supplements by at least 2 hours.

Scientific references

Related in Weight management

Herbal medicines: what the evidence says (335)