Red yeast rice: Evidence, Trial Doses & Interactions

About Red yeast rice

Rice fermented with the mould Monascus purpureus, which produces monacolin K — a molecule chemically identical to the prescription statin lovastatin. It is a drug delivered as a food product.

Red yeast rice works because it contains a statin, and it carries statin risks for the same reason. Monacolin content in retail products has been found to vary from undetectable to more than 10 mg per daily dose in the same market, meaning the consumer cannot know their statin dose. Some products have also been contaminated with citrinin, a nephrotoxic mould metabolite. Anyone whose cholesterol warrants a statin is better served by a measured prescription dose with liver monitoring.

Sold as

Capsule, Tablet, Powder, Traditional fermented rice

Standardised to

Some products state monacolin K content; many do not, and measured content frequently differs from label — a product without this marker may not resemble what was studied.

Also known as

Hong qu, Monascus, Red koji rice, Xuezhikang

Regulation: The EU restricted monacolin K in food supplements to below 3 mg per day in 2022 after a safety review. The US FDA has taken enforcement action against products with lovastatin-equivalent monacolin levels, treating them as unapproved drugs. Availability and legality vary considerably by country.

What the research used

The amounts, forms and durations published trials of Red yeast rice actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

Studied for LDL cholesterol reduction
2.4–10 mg
Moderate
Monacolin K from red yeast rice, daily · 8 weeks to 4 years
Trials specify monacolin K, but retail products rarely do, and independent testing has found up to hundred-fold differences between brands. A 1,200 mg capsule of red yeast rice tells you nothing about the statin dose inside it.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

Evening
Limited
Taken in the evening by analogy with short-acting statins, whose effect is greater at night because cholesterol synthesis peaks then. That reasoning comes from statin pharmacology rather than from any trial of red yeast rice timing.
Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

Blood lipid profile

Heart Health

Strong evidence

Multiple randomised trials and meta-analyses report LDL cholesterol reductions of roughly 15 to 25 percent, comparable to a low-dose statin. That is unsurprising: the active compound is chemically identical to lovastatin. The uncertainty is not whether it works but how much of it any given product contains.

What may be going on: Monacolin K inhibits HMG-CoA reductase, the same enzyme targeted by prescription statins.

Strong evidence. Consistent findings across multiple good-quality human studies.

View the 2 sources

Safety and Efficacy of the Consumption of the Nutraceutical "Red Yeast Rice Extract" for the Reduction of Hypercholesterolemia in Humans: A Systematic Review and Meta-Analysis.(opens in a new tab)
Meta-analysis · Nutrients · 2024 · PMID 38794691
Monacolin K supplementation in patients with hypercholesterolemia: A systematic review of clinical trials.(opens in a new tab)
Systematic review · Semergen · 2024 · PMID 38310834

Deep research mode adds each paper’s own conclusion and stated limitations.

Cardiovascular risk markers

Heart Health

Limited evidence

One large Chinese secondary prevention trial reported fewer coronary events with a red yeast rice preparation. It has not been replicated outside China, and the preparation used is not what is generally sold elsewhere.

Limited evidence. Early human work, or mostly lab and animal research.

View the 3 sources

[Adjunctive therapy of xuezhikang capsule for coronary heart disease: a systematic review and meta-analysis of randomized controlled trials].(opens in a new tab)
Meta-analysis · Zhongguo Zhong xi yi jie he za zhi Zhongguo Zhongxiyi jiehe zazhi = Chinese journal of integrated traditional and Western medicine · 2014 · PMID 25509259
Effects of Xuezhikang in patients with dyslipidemia: a multicenter, randomized, placebo-controlled study.(opens in a new tab)
Randomised controlled trial · Journal of clinical lipidology · 2014 · PMID 25499939
Beneficial impact of Xuezhikang on cardiovascular events and mortality in elderly hypertensive patients with previous myocardial infarction from the China Coronary Secondary Prevention Study (CCSPS).(opens in a new tab)
Randomised controlled trial · Journal of clinical pharmacology · 2009 · PMID 19602720

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

Worth knowing
It carries the full risk profile of a statin
Muscle pain, raised creatine kinase, rhabdomyolysis and liver enzyme elevation have all been reported with red yeast rice, exactly as with lovastatin. Unexplained muscle pain or weakness, dark urine or jaundice needs prompt medical assessment.
Worth knowing
Unpredictable and unlabelled dose
Independent analyses have found monacolin K content ranging from none to more than a prescription-equivalent dose across products with identical labels. Nobody taking it knows what statin dose they are on, and some products have been found to contain the nephrotoxic mycotoxin citrinin.
Interaction
Statin-type drug interactions
Interacts withStatins, fibrates, clarithromycin, itraconazole, ciclosporin, grapefruit juice
Combining it with a prescribed statin, fibrates, macrolide antibiotics, some antifungals, ciclosporin or grapefruit juice raises the risk of muscle toxicity through the same CYP3A4 pathway that affects lovastatin.
Avoid
Pregnancy, breastfeeding and liver disease
Statins are contraindicated in pregnancy because of fetal harm, and the same applies here. It should also be avoided in active liver disease and by anyone who has had statin-related muscle injury.
Worth knowing
Coenzyme Q10 depletion
Like statins, monacolin K reduces coenzyme Q10 synthesis. Whether that matters clinically is debated, but it is part of the same pharmacology.

Red yeast rice

What red yeast rice may help with

About Red yeast rice

What the research used

When it was taken

Evening

The evidence in depth

Blood lipid profile

Cardiovascular risk markers

Things to know

It carries the full risk profile of a statin

Unpredictable and unlabelled dose

Statin-type drug interactions

Pregnancy, breastfeeding and liver disease

Coenzyme Q10 depletion

What red yeast rice may help with

About Red yeast rice

What the research used

When it was taken

🌙Evening

The evidence in depth

Blood lipid profile

Cardiovascular risk markers

Things to know

It carries the full risk profile of a statin

Unpredictable and unlabelled dose

Statin-type drug interactions

Pregnancy, breastfeeding and liver disease

Coenzyme Q10 depletion

Evening