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Limited evidenceHeart & metabolic

Black Tea Theaflavins

Theaflavins are the pigments that make black tea black, sold as a liver-friendlier alternative to high-dose EGCG for cholesterol. The landmark trial used a mixed extract that also contained green tea catechins, so the theaflavin-specific evidence is far thinner than the marketing implies.

What the science says

  • Lowers LDL cholesterol Limited evidence

    In the best-known RCT (n = 240, 12 weeks, mildly hypercholesterolemic adults on a low-fat diet), a theaflavin-enriched green tea extract lowered total cholesterol by 11.3% and LDL-C by 16.4% relative to placebo. Critically, the capsule contained 75 mg of theaflavins alongside roughly 150 mg of green tea catechins and other polyphenols — the effect cannot be attributed to theaflavins, and theaflavin-only trials have not convincingly reproduced it.

  • Reduces body fat Limited evidence

    A 10-week randomized, double-blind pilot in 30 Japanese adults reported that 50–100 mg/day of theaflavin improved body fat percentage, subcutaneous fat and skeletal muscle percentage versus placebo, while 400 mg of catechin did not. Thirty participants split across four arms is a hypothesis-generating pilot, not a basis for buying a fat-loss product.

  • Antimicrobial and oral-health effects Limited evidence

    Theaflavins inhibit oral bacteria and several viruses in vitro, and a small randomized placebo-controlled study in Japanese subjects found effects on oral bacterial counts. There are no clinical endpoint data — no caries, gingivitis or infection outcomes.

Dosage & safety

Studied doseStudies used 75 mg/day of theaflavins within a mixed tea extract, or 50–100 mg/day of isolated theaflavins, over 10–12 weeks. Commercial black tea extracts are typically standardised to 20–40% theaflavins at 300–500 mg per capsule, which lands in or above the studied range — but many also carry undeclared catechins and caffeine.
SafetyTheaflavins are large, poorly absorbed molecules and are generally well tolerated; GI upset is the most common complaint. Unlike high-dose EGCG, isolated theaflavins have not been associated with hepatotoxicity — but many products labelled "black tea extract" also contain green tea catechins, so read the full label if liver safety is the reason you chose them. Tea polyphenols substantially reduce non-heme iron absorption when taken with meals; take away from iron-rich meals or iron supplements. Caffeine content varies by product. Not studied in pregnancy at supplemental doses.

Scientific references

Where to buy

Life Extension, Theaflavin, Standardized Black Tea Extract, 30 Vegetarian Capsules (400 mg per Capsule)

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