Awaiting clinical review. This entry is sourced but has not yet been signed off by a pharmacist or clinician.

Aspalathus linearis (leaf, as tea)

Rooibos

Rooibos is a caffeine-free herbal tea, and small human trials suggest it may improve blood fats and markers of oxidative stress, but the studies are few and small, so it is not proven to do anything for your health. It is widely drunk without problems. The main caution is a handful of case reports of liver injury in heavy or regular drinkers, which look rare but are not well understood.

Written by

Healthy and Herbal editorial team

Updated

29 September 2026

Loose red rooibos tea and a cup of rooibos

At a glance

Last reviewed 29 September 2026

Evidence

Limited

Best for

Cholesterol and oxidative markers

Typical form & use

Fermented tea, six cups a day

Onset

4+ weeks

Safety

Rare liver injury case reports. No interactions in our data.

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What it's used for

Evidence is rated per use. The same ingredient can be strong for one thing and traditional for another.

Use	Evidence	What the research shows
Cholesterol and oxidative stress markers	Limited	In a 6-week crossover study of 40 adults at risk of heart disease drinking six cups of fermented rooibos a day, LDL-cholesterol fell from 4.6 to 3.9 mmol/L, triacylglycerols fell from 1.7 to 1.2 mmol/L, HDL rose from 0.9 to 1.2 mmol/L and markers of lipid peroxidation fell. It had no control group receiving a matched drink, and these are blood markers, not heart attacks or strokes. A 2023 scoping review of 18 human studies (488 participants) found benefits on lipids and antioxidant status but called the evidence limited, with inconsistent results across doses and tea types.^1,2
Heart structure and blood pressure pathways	Limited	A 12-week double-blind trial of green and fermented rooibos capsules against placebo in adults at cardiovascular risk found left ventricular mass fell only in the fermented group (204 to 191 g), but the placebo group also showed changes in septum thickness, so the results are hard to read. In 17 healthy volunteers a single 400 ml cup of rooibos reduced angiotensin-converting enzyme activity for about an hour, with no change in nitric oxide. Neither abstract reports blood pressure or heart events as an outcome.^3,4
Blood sugar	Traditional	The 2023 scoping review reports lower blood glucose in some of its included human studies, but we did not read those trials and the review says the total evidence is small. We rate this on the traditional and preliminary record; no human trial we opened tested rooibos in people with diabetes.¹

How much

Ranges below are what studies used and what supplements commonly contain. They are not a recommendation for you. Start at the low end.

Studied range

200–1,200 ml tea per day¹

The scoping review found human studies used 200 to 1,200 ml; no human dose-response study has been done.

Best-studied regimen

Six cups daily for 6 weeks²

The lipid and oxidative-stress trial used fermented (traditional red) rooibos, six cups (one bag per 200 ml) a day.

Upper limit

Not established¹

The scoping review notes that with so few controlled trials it is uncertain whether an overdose or long-term heavy use causes liver harm. No safe upper intake has been set in any source we opened.

Timing · No source we read gave timing advice. Because rooibos contains no caffeine, it is not expected to keep you awake, but we did not find a trial testing evening use.With food? · No source we read gave food guidance. Studies used the tea with or without milk and sugar; we found no evidence either way on effect.How long to trial · The main trial ran for 6 weeks before measuring blood markers, so judge any effect over about 4 to 6 weeks, and by a blood test rather than by how you feel.

How people take it

Fermented (red) tea bags or loose leafUp to six cups a day in the main trialThe form with the most human data. Brewed from oxidised leaf; this is the ordinary supermarket rooibos.

Unfermented (green) rooibosVariesHigher in the flavonoid aspalathin. Tested in a 12-week trial as a capsule extract, but too little human data to compare with fermented tea.

Standardised extract capsuleVaries by productUsed in the 12-week trial. Extract strength differs by product, so the tea trials do not transfer directly.

Safety

Who should avoid

Unexplained abnormal liver tests or liver disease — case reports of liver injury
Anyone who develops jaundice, dark urine or upper-right abdominal pain — stop and seek care
Pregnancy and breastfeeding — no trial data; ask your midwife or doctor about heavy intake

Known interactions

No interactions in our data. Absence of a flag is not clearance.

Questions people ask

Is rooibos caffeine-free?

Yes. A 2023 scoping review describes rooibos tea as free of caffeine and low in tannins, unlike green or black tea from the Camellia sinensis plant.

Can rooibos damage your liver?

Rarely, if at all. Several case reports describe liver injury in people who drank rooibos (we read three), including one biopsy-confirmed case in a man drinking a rooibos and buchu tea who recovered after stopping it. Case reports cannot show that rooibos caused the injury or how often it happens, and other liver risks were not always fully excluded.

Does rooibos lower cholesterol or blood sugar?

A small 6-week study of adults at cardiovascular risk found lower LDL-cholesterol and triacylglycerols after six cups a day. Evidence on blood sugar is thinner and comes from a summary review of small studies, so treat both as suggestive rather than proven.

Is rooibos safe in pregnancy?

We found no trial or regulator statement on rooibos in pregnancy, so we cannot say it is either proven safe or unsafe. Ask your midwife or doctor if you plan to drink a lot.

Sources

Last reviewed 29 September 2026 · Next review March 2027 · How we rate evidence