Red yeast rice

What it is

Red yeast rice is rice that has been fermented with a mould: "Red yeast rice is produced by fermentation of a fungus on rice". The fermentation produces a family of compounds called monacolins, of which the main one, monacolin K, "is chemically identical to lovastatin, a commercially available HMG-coenzyme A inhibitor". How much monacolin K a product contains is not fixed: in a 37-product survey, nine products had less than the label said and 24 had more, and a separate analysis found "total monacolin concentrations varied from 0.3-11.1 mg/capsule". Some products also carry the mould toxin citrinin.

What the research says

The evidence that red yeast rice lowers LDL cholesterol is consistent across a large number of randomised trials, but the reviews that pool them are themselves rated poor quality, and the safety reporting inside the trials is weak. A 2015 systematic review of 20 randomised trials in 6,663 patients found a pooled placebo-subtracted LDL reduction of −1.02 mmol/L, while stating that the adverse-event data were too thin to judge safety. Because monacolin K is the same molecule as the prescription statin lovastatin, the expected harms are statin harms - muscle and liver effects - and both liver injury case reports and citrinin contamination have been documented.

Evidence grade: Limited evidence.

What goes wrong

Isolated case reports describe liver injury in people taking red yeast rice extracts, and the mechanism is attributed to the lovastatin present in the product. (Source 1)

• Case report, Low certainty.
• Size: not quantified beyond "isolated case reports"
• Who: patients taking red yeast rice extracts.
• How long: not stated.
• Result: no rate given; injury attributed to lovastatin at 1 to 10 mg per tablet.
• Funding: not stated.

However, there have been isolated case reports of liver injury in patients on red yeast rice extracts.

Because monacolin K is lovastatin, the expected liver signal is the statin one: ALT above three times the upper limit of normal in 0.4% of lovastatin recipients versus 0.1% on placebo. (Source 2)

• Expert review, not systematic, Moderate certainty.
• Size: not stated (pooled clinical trial experience with lovastatin)
• Who: patients treated with lovastatin.
• How long: not stated.
• Result: "ALT elevations above normal occurred in 3% to 5% of patients, but were above 3 times the upper limit of normal (ULN) in only 0.4% compared to 0.1% of placebo recipients."
• Funding: US government resource (NIDDK)

ALT elevations above normal occurred in 3% to 5% of patients, but were above 3 times the upper limit of normal (ULN) in only 0.4% compared to 0.1% of placebo recipients.

In a survey of 37 red yeast rice supplements, the nephrotoxic mould toxin citrinin was found in every product tested, at 100 to 25,100 micrograms per kilogram. (Source 3)

• Survey study, Moderate certainty.
• Size: Thirty-seven red yeast rice (RYR) food supplements.
• Who: commercial food supplements on sale, not people.
• How long: not applicable.
• Result: citrinin in all 37 products, range 100 to 25100 micrograms/kg; monacolin K from −30% to −83% below label in nine products and 10% to 266% above label in 24.
• Funding: not stated.

citrinin (CIT) was found in all the monitored products. As CIT content ranged from 100 to 25100 μg/kg

Monacolin K content in commercial red yeast rice products varies enough that the same labelled dose can deliver very different amounts of an active statin. (Source 4)

• Survey study, Moderate certainty.
• Size: Thirty-seven red yeast rice (RYR) food supplements.
• Who: commercial supplements.
• How long: not applicable.
• Result: "nine products had a lower content vs. label statements (from −30 to −83%), while for 24 a larger MK amount (from 10 to 266%) was noticed."
• Funding: not stated.

nine products had a lower content vs. label statements (from −30 to −83%), while for 24 a larger MK amount (from 10 to 266%) was noticed.

The 2015 systematic review judged that the trials did not report adverse events well enough to support a safety conclusion. (Source 5)

• Systematic review, Low certainty.
• Size: 20 randomized trials on 6663 patients.
• Who: trial participants taking red yeast rice extract.
• How long: not stated.
• Result: "The incidence of kidney injury and liver abnormalities was <5% in both RYR and control groups. The rate of myopathy did not differ between RYR and control groups." - but reporting was judged insufficient.
• Funding: not stated.

The design and reporting of adverse events were in most studies insufficient to make a firm judgement on the safety of red yeast rice extract.

NCCIH's position, updated November 2022, is that red yeast rice products containing meaningful monacolin K can carry statin side effects and statin drug interactions, and that products with enhanced lovastatin cannot legally be sold as dietary supplements in the United States. (Source 6)

• Official position, Certainty not rated.
• Size: not applicable.
• Who: US consumers.
• How long: not applicable.
• Result: no numbers; a 2017 analysis cited on the page found monacolin K "ranged more than 60-fold, from 0.09 to 5.48 mg per 1,200 mg of red yeast rice"
• Funding: US government agency.

Red yeast rice products that contain significant amounts of monacolin K can have the same potential side effects as statin drugs, including muscle, kidney, and liver damage.

What the evidence supports

Pooling 20 randomised trials, red yeast rice extract lowered LDL cholesterol by about 1 mmol/L compared with placebo. (Source 5)

• Systematic review, Moderate certainty.
• Size: 20 randomised trials on 6663 patients.
• Who: patients in trials of red yeast rice extract for cardiovascular risk reduction.
• How long: not stated in the abstract.
• Result: "The placebo-subtracted reduction of LDL was 0.68 till 1.44 mmol/l with a pooled estimate of −1.02 mmol/L (95% CI −1.20; −0.83)."
• Funding: not stated.

We analyzed 20 randomized trials on 6663 patients. The placebo-subtracted reduction of LDL was 0.68 till 1.44 mmol/l with a pooled estimate of −1.02 mmol/L (95% CI −1.20; −0.83).

A meta-analysis of 13 placebo-controlled trials found significant reductions in total cholesterol, triglycerides and LDL cholesterol with red yeast rice. (Source 7)

• Meta-analysis, Low certainty.
• Size: 13 randomized, placebo-controlled trials containing 804 participants.
• Who: patients with dyslipidemia.
• How long: treatment duration was 4 weeks or longer in all included trials.
• Result: TC WMD −0.97 mmol/L (95% CI −1.13, −0.80), P<0.001; TG WMD −0.23 mmol/L (95% CI −0.31, −0.14), P<0.001; LDL-C WMD −0.87 mmol/L (95% CI −1.03, −0.71), P<0.001.
• Funding: not stated.

Red yeast rice exhibited significant lowering effects on serum TC [WMD = −0.97 (95% CI: −1.13, −0.80) mmol/L, P<0.001], TG [WMD = −0.23 (95% CI: −0.31, −0.14) mmol/L, P<0.001], and LDL-C [WMD = −0.87 (95% CI: −1.03, −0.71) mmol/L, P<0.001]

In a 12-week randomised placebo-controlled trial, a supplement delivering 3 mg of monacolin K per day lowered LDL cholesterol by about 15%. (Source 8)

• Randomized trial, Moderate certainty.
• Size: One hundred forty-two nonstatin-treated participants.
• Who: participants with hypercholesterolemia (LDL-C between 4.14 and 5.69 mmol/L) not taking statins.
• How long: 12 weeks.
• Result: LDL-C −14.8%, total cholesterol −11.2%, homocysteine −12.5%, all P < .001 versus baseline in the supplement group.
• Funding: not stated.

A significant (P < .001) reduction of LDL-C (−14.8%), total cholesterol (−11.2%), and homocysteine (−12.5%) was determined in the supplement group after 12 weeks.

What the evidence does not support

In the same 13-trial meta-analysis, red yeast rice did not significantly raise HDL cholesterol. (Source 7)

• Meta-analysis, Low certainty.
• Size: 13 randomized, placebo-controlled trials containing 804 participants.
• Who: patients with dyslipidemia.
• How long: 4 weeks or longer.
• Result: HDL-C WMD = 0.08 mmol/L (95% CI −0.02, 0.19), P = 0.11.
• Funding: not stated.

no significant increasing effect on HDL-C [WMD = 0.08 (95% CI: −0.02, 0.19) mmol/L, P = 0.11] compared with placebo

Head-to-head against statins, red yeast rice was less effective at lowering total cholesterol. (Source 9)

• Meta-analysis, Low certainty.
• Size: A total of 1,012 individuals participated in this study (481 in the experimental and 531 in the control group)
• Who: patients with hyperlipidemia across 15 randomised controlled trials.
• How long: not stated in the extracted text.
• Result: "less effective in lowering TC (MD, 12.24; 95% CI, 2.19 to 22.29; p = 0.02)"
• Funding: not stated.

less effective in lowering TC (MD, 12.24; 95% CI, 2.19 to 22.29; p = 0.02)

An overview of 31 systematic reviews found that almost all of the reviews of red yeast rice were at high risk of bias and of low or critically low confidence. (Source 10)

• Review of reviews, Very low certainty.
• Size: Thirty-one systematic reviews (SRs) involving 165 randomized trials with 14,987 dyslipidemia participants.
• Who: adults with dyslipidemia in the underlying randomised trials.
• How long: varied.
• Result: AMSTAR 2 confidence: "one SR had moderate confidence, and 30 had an overall low (7) or critically low (23)"
• Funding: not stated.

Based on the ROBIS, all the SRs showed a high overall risk of bias

Where the evidence is mixed

In a 4-week randomised pilot trial against simvastatin, muscle fatigue scores rose on simvastatin but did not change measurably on red yeast rice. (Source 11)

• Randomized trial, Very low certainty.
• Size: A total of 60 dyslipidemic patients (simvastatin n = 33, red yeast rice n = 27)
• Who: dyslipidemic patients with low to moderate cardiovascular risk.
• How long: 4 weeks.
• Result: "the fatigue score was significantly increased in patients treated with simvastatin, whereas no significant change was observed in patients receiving red yeast rice"
• Funding: not stated in the abstract; the article's Declarations record Funding as not applicable. The trial is registered as NCT01686451.

At the end of study, the fatigue score was significantly increased in patients treated with simvastatin, whereas no significant change was observed in patients receiving red yeast rice.

Where the research disagrees

Whether red yeast rice can be called safe on current trial evidence

• Gerards and colleagues, Atherosclerosis 2015 systematic review, systematic review of 20 randomised trials: "The design and reporting of adverse events were in most studies insufficient to make a firm judgement on the safety of red yeast rice extract." (Source 5)
• Xiong and colleagues, PLOS One 2014 meta-analysis, meta-analysis of 13 placebo-controlled trials: "No serious side effects were reported in all trials." (Source 7)

Whether the product quality problem undermines the efficacy and safety literature

• Fontana and colleagues, Frontiers in Nutrition 2021, analytical survey of 37 commercial supplements: "These results suggest that limited efficacy and reported safety issues may stem from an under-regulated and undercontrolled market, weakening both effectiveness and risk assessment evaluations." (Source 12)
• Frontiers in Pharmacology 2021 meta-analysis of 15 randomised trials, meta-analysis of randomised trials: "did not increase the risk of adverse events in patients with hyperlipidemia" (Source 13)

How much

• Reference intake: No dietary reference intake exists for red yeast rice or monacolin K. It is a fermented food product rather than an essential nutrient: NCCIH describes it as produced "by fermentation of a fungus on rice". We could not reach the EFSA 2025 opinion on monacolins (403 error) to record an EU reference figure. (Source 14)
• Upper limit: No tolerable upper intake level has been set by a nutrition body that we could reach. The nearest regulatory statement we could obtain is the US position that "According to the FDA, red yeast rice products that have enhanced or added lovastatin—which is structurally identical to monacolin K—cannot be marketed as a dietary supplement in the United States." The EFSA 2025 scientific opinion on monacolins could not be reached on any host tried, so no EU figure is recorded here. (Source 15)
• Studied: A 12-week randomised placebo-controlled trial gave a supplement containing "3 mg monacolin K and 200 μg folic acid per day". (Source 16)
• Studied: The 15-trial meta-analysis states that "RYR at 200–4800 mg daily appears to be a safe and effective treatment for hyperlipidemia". (Source 17)
• Studied: The same meta-analysis describes low-dose products, saying that "the risk related to low doses of RYR (containing 3–10 mg monacolin K) taken per day is minimal". (Source 18)

A common belief, and what the research shows

The belief: Red yeast rice is a gentle natural alternative to a statin, so it does not carry statin risks.

What the research shows: Its active compound is the same molecule as a prescription statin. LiverTox states that monacolin K "is chemically identical to lovastatin, a commercially available HMG-coenzyme A inhibitor", and that "Both the liver injury and myopathies attributed to red yeast rice extracts are probably due to the presence of lovastatin in concentrations of 1 to 10 mg per tablet." NCCIH adds that these products "can have the same types of drug interactions as statin drugs and therefore may interfere with certain medicines or increase the chance for side effects."

Questions and answers

What is it?

Red yeast rice is rice fermented with a mould, traditionally Monascus purpureus, which gives it a deep red colour. The fermentation produces compounds called monacolins. It has been used as a food colouring and flavouring in East Asia and is now sold as a cholesterol supplement. (Source 14)

What does it do in the body?

Its main active compound, monacolin K, is the same chemical as the prescription statin lovastatin, which blocks an enzyme the body uses to make cholesterol. That is why red yeast rice lowers LDL cholesterol, and also why it can produce statin-type muscle and liver effects. (Source 19)

Is it good or bad for you?

Both, depending on what you measure. Pooled across 20 randomised trials it lowered LDL cholesterol by about 1 mmol/L, which is a real effect. But the same review said the trials did not record side effects well enough to conclude it is safe, and separate work shows liver injury reports and citrinin contamination. (Source 5)

How do you get more of it?

Trials have used capsules of red yeast rice extract standardised to a stated amount of monacolin K. One 12-week randomised trial gave a supplement providing 3 mg of monacolin K plus folic acid daily; meta-analysed trials used red yeast rice from 200 mg to 4800 mg a day. This is what was studied, not a recommendation. (Source 16)

If it is harmful, what reduces it?

The literature we found does not describe any way to remove red yeast rice or monacolin K from the body; it is cleared like the statin it contains. What the literature does address is avoiding exposure: the injuries reported are attributed to the lovastatin content of the tablets, and product content varies widely. (Source 20)

Why might someone be low in it or missing it?

This question does not really apply. Red yeast rice is a fermented food product and a supplement ingredient, not a substance your body makes or needs, so there is no deficiency to be low in. Someone simply has none of it unless they eat or take it. (Source 14)

Which whole foods contain it or feed it?

Red yeast rice itself is the food: rice fermented with the Monascus mould, used in Chinese cooking as a colouring and flavouring. Ordinary white rice does not contain monacolins. Concentrated supplement extracts contain far more monacolin K than the culinary product, and how much is unpredictable. (Source 21)

What happens if you do not have it?

Nothing. There is no red yeast rice deficiency state described in the literature, because it is a fermented food and supplement ingredient rather than a nutrient the body requires. The literature on it deals with whether taking it lowers cholesterol, not with what happens without it. (Source 14)

We searched: We searched for red yeast rice deficiency, requirement and reference intake alongside the systematic reviews, NCCIH and LiverTox monographs; none describes a deficiency state or a requirement.

How can you test for it?

There is no blood test for red yeast rice status. What can be tested is the product: laboratories measure monacolin K and citrinin by chromatography, and those analyses repeatedly find contents that differ from the label. Cholesterol and liver enzyme tests measure the effect, not the substance. (Source 22)

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Red Yeast Rice - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. 2018. Read the source
2. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Lovastatin - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. 2021. Read the source
3. Frontiers in Nutrition. Risk Assessment of RYR Food Supplements: Perception vs. Reality. 2021. DOI 10.3389/fnut.2021.792529. Read the source
4. Frontiers in Nutrition. Risk Assessment of RYR Food Supplements: Perception vs. Reality. 2021. DOI 10.3389/fnut.2021.792529. Read the source
5. Atherosclerosis. Traditional Chinese lipid-lowering agent red yeast rice results in significant LDL reduction but safety is uncertain - A systematic review and meta-analysis. 2015. PMID 25897793, DOI 10.1016/j.atherosclerosis.2015.04.004. Read the source
6. National Center for Complementary and Integrative Health (NCCIH), NIH. Red Yeast Rice: What You Need To Know. 2022. Read the source
7. PLOS One. A Meta-Analysis of Red Yeast Rice: An Effective and Relatively Safe Alternative Approach for Dyslipidemia. 2014. PMID 24897342, DOI 10.1371/journal.pone.0098611. Read the source
8. Nutrition Research. Low daily dose of 3 mg monacolin K from RYR reduces the concentration of LDL-C in a randomized, placebo-controlled intervention. 2016. PMID 27865358, DOI 10.1016/j.nutres.2016.07.005. Read the source
9. Frontiers in Pharmacology. Red Yeast Rice for Hyperlipidemia: A Meta-Analysis of 15 High-Quality Randomized Controlled Trials. 2022. PMID 35111069, DOI 10.3389/fphar.2021.819482. Read the source
10. Journal of Functional Foods. Red yeast rice preparations for dyslipidemia: An overview of systematic reviews and network meta-analysis. 2023. DOI 10.1016/j.jff.2023.105508. Read the source
11. BMC Cardiovascular Disorders. Red yeast rice induces less muscle fatigue symptom than simvastatin in dyslipidemic patients: a single center randomized pilot trial. 2017. PMID 28521773, DOI 10.1186/s12872-017-0560-z. Read the source
12. Frontiers in Nutrition. Risk Assessment of RYR Food Supplements: Perception vs. Reality. 2021. DOI 10.3389/fnut.2021.792529. Read the source
13. Frontiers in Pharmacology. Red Yeast Rice for Hyperlipidemia: A Meta-Analysis of 15 High-Quality Randomized Controlled Trials. 2022. PMID 35111069, DOI 10.3389/fphar.2021.819482. Read the source
14. National Center for Complementary and Integrative Health (NCCIH), NIH. Red Yeast Rice: What You Need To Know. 2022. Read the source
15. National Center for Complementary and Integrative Health (NCCIH), NIH. Red Yeast Rice: What You Need To Know. 2022. Read the source
16. Nutrition Research. Low daily dose of 3 mg monacolin K from RYR reduces the concentration of LDL-C in a randomized, placebo-controlled intervention. 2016. PMID 27865358, DOI 10.1016/j.nutres.2016.07.005. Read the source
17. Frontiers in Pharmacology. Red Yeast Rice for Hyperlipidemia: A Meta-Analysis of 15 High-Quality Randomized Controlled Trials. 2022. PMID 35111069, DOI 10.3389/fphar.2021.819482. Read the source
18. Frontiers in Pharmacology. Red Yeast Rice for Hyperlipidemia: A Meta-Analysis of 15 High-Quality Randomized Controlled Trials. 2022. PMID 35111069, DOI 10.3389/fphar.2021.819482. Read the source
19. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Red Yeast Rice - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. 2018. Read the source
20. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Red Yeast Rice - LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. 2018. Read the source
21. National Center for Complementary and Integrative Health (NCCIH), NIH. Red Yeast Rice: What You Need To Know. 2022. Read the source
22. Frontiers in Nutrition. Risk Assessment of RYR Food Supplements: Perception vs. Reality. 2021. DOI 10.3389/fnut.2021.792529. Read the source