Red Yeast Rice
Red yeast rice is sold over the counter as a natural way to lower cholesterol. Its active ingredient is chemically the prescription statin lovastatin, at doses most labels outside the EU don't state, European regulators could find no daily intake free of safety concerns, and in 2024 a contaminated product in Japan was linked to kidney injury in 192 people, most of whom still had reduced kidney function at follow-up.
Skip red yeast rice. If you need lower LDL ("bad") cholesterol, take a prescribed statin at a known dose, with monitoring.
What it is: an unlabelled statin
Red yeast rice is rice fermented with the mould Monascus. It is not a gentle botanical alternative to a statin. Its active constituent, monacolin K, is in its lactone form the same molecule as lovastatin, a prescription statin, and the amounts delivered by supplements can reach the therapeutic dose range of that drug.[1]
The difference from the drug is that you don't know the dose. A prescribed statin comes with a stated amount and with monitoring; a fermented supplement's statin content is neither labelled nor regulated in most of the world.
The European limits
Since June 2022, European Union (EU) law caps what a product sold in Europe may deliver. A daily portion must provide less than 3 mg of monacolins, the label must state the content per portion, and it must warn against use in pregnancy, under 18, over 70, and alongside cholesterol-lowering medication.[2] Products bought outside the EU carry no such limit.
The cap does not make the low dose safe. The European Food Safety Authority (EFSA) could not identify any daily intake of monacolins from red yeast rice that does not raise safety concerns. Severe reactions — muscle breakdown (rhabdomyolysis) and liver injury — have been reported at intakes as low as 3 mg a day of monacolin K, and a 2025 re-examination of newer post-marketing data reached the same conclusion.[3]
The 2024 Japanese kidney injuries
A fermented supplement also carries a manufacturing risk you cannot check at home. After a 2024 recall of Beni-koji (red yeast rice) tablets in Japan, a two-phase nationwide survey of kidney specialists collected 192 affected patients.
- Most had kidney damage. 94% had reduced kidney function, with the laboratory picture of Fanconi syndrome, in which the kidney tubules leak potassium, phosphate, uric acid and glucose. Biopsies showed inflammation of the kidney tissue (tubulointerstitial nephritis) in half the biopsies and dead tubule cells (tubular necrosis) in about a third.
- It largely did not reverse. After the product was stopped and patients were treated, the tubule-leak markers improved, but 87% still had reduced kidney function at last follow-up.
- Causality is not closed. The authors are explicit that further research is needed to establish it.[4]
Investigators traced the injury to a factory contaminant, not the Monascus mould used to ferment the rice. Citrinin, the kidney toxin classically feared in red yeast rice, was not produced by the implicated strains; investigators traced the injury to puberulic acid, made by a Penicillium mould growing in the production plant.[5]
What to do
- Don't use red yeast rice to lower cholesterol. You get an unknown statin dose with none of the monitoring.
- Never combine it with a prescribed statin or other cholesterol medication, and avoid it in pregnancy.
- If your LDL needs lowering, see a clinician about a prescribed statin. The options are on Lipid management; other supplements with a harm record are on Supplements to avoid.
Further reading
- Younes M et al. Scientific opinion on the safety of monacolins in red yeast rice. EFSA J 2018.[6]
- Turck D et al. Scientific Opinion on additional scientific data related to the safety of monacolins from red yeast rice submitted pursuant to Article 8(4) of Regulation (EC) No 1925/2006. EFSA J 2025.[7]
- Shinzawa M et al. A nationwide questionnaire study evaluated kidney injury associated with Beni-koji tablets in Japan. Kidney Int 2025.[8]
- Yoshinari T et al. Mechanism of puberulic acid contamination in red yeast rice tablets that caused a serious food poisoning outbreak in Japan. Proc Jpn Acad Ser B Phys Biol Sci 2025.[9]