Supplement analysis backed by scientific evidence · PT

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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.

Evidence last reviewed: August 2026

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.

Scientific references

Where to buy

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