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Limited evidenceLongevity & antioxidants

Rooibos Extract

A caffeine-free South African tea rich in aspalathin. A few small human studies show changes in stress hormone ratios and vascular markers, but the effects are modest and not consistently replicated.

Evidence last reviewed: August 2026

What the science says

  • Cardiovascular markers Limited evidence

    A randomized study of chronic herbal rooibos consumption in adults at cardiovascular risk measured effects on cardiovascular function and found limited changes. The sample was small and the endpoints were surrogate markers rather than events.

  • Stress hormones and metabolic effects Limited evidence

    A clinical study combined with in vitro work found rooibos consumption shifted glucocorticoid levels and steroid ratios in adults at risk of cardiovascular disease. The human arm was small and uncontrolled by modern standards, so the finding is hypothesis-generating.

Dosage & safety

Studied doseHuman studies used roughly six cups of rooibos tea a day for six weeks, or fermented rooibos extract equivalents. Capsule extracts typically supply 200–500 mg/day as a label dose.
SafetyRooibos tea is well tolerated and caffeine-free. Rare cases of liver injury have been reported with concentrated rooibos preparations. It contains compounds that may affect steroid hormone metabolism and oestrogenic signalling in vitro, so caution is reasonable in hormone-sensitive conditions and during breast cancer treatment.

Scientific references

Where to buy

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