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.

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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.

How to take it

TimingTiming does not matter, and being caffeine-free it works as an evening drink.

With food?With or without food.

Worth knowingThe human data used ordinary fermented rooibos tea at about six cups a day, so drinking it is closer to the evidence than any capsule.

Frequently asked questions

Is rooibos good for your heart?

The evidence is limited: a small randomized study of rooibos tea in adults at cardiovascular risk found only limited changes in cardiovascular function markers. No study has measured heart attacks or other real events.

Does rooibos lower cortisol or stress hormones?

One small study found rooibos consumption shifted glucocorticoid levels and steroid ratios in adults at cardiovascular risk. It was small and not well controlled, so the finding is hypothesis-generating, not proof.

How much rooibos should I drink per day?

Human studies used roughly six cups of fermented rooibos tea a day for six weeks, so drinking the tea is closer to the evidence than any capsule. Extract capsules typically supply 200–500 mg/day as a label dose.

Is rooibos safe to drink every day?

Rooibos tea is well tolerated and caffeine-free, so it works as an evening drink. Rare liver injury has been reported with concentrated rooibos preparations, and caution is reasonable in hormone-sensitive conditions and during breast cancer treatment.

Scientific references

Impact of Chronic Consumption of Herbal Rooibos on Cardiovascular Function in Adults with Cardiovascular Risk
Hartnick MD, Marnewick JL, Engel-Hills P — J Med Food, 2024
Rooibos influences glucocorticoid levels and steroid ratios in vivo and in vitro: a natural approach in the management of stress and metabolic disorders?
Schloms L, Smith C, Storbeck KH — Mol Nutr Food Res, 2014

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