The Side Effects of Red Yeast Rice

Red yeast rice capsules and tablets

Verywell / Anastasia Tretiak

A dietary supplement often used for cholesterol control, red yeast rice is associated with a number of side effects. If you're considering the use of red yeast rice, it's important to learn about these potential side effects before you start taking the supplement.

Long used in traditional Chinese medicine, red yeast rice is produced by fermenting a type of red yeast (Monascus purpureus) over rice. It contains a class of substances called monacolins, which includes lovastatin (the active ingredient in a number of prescription drugs used to treat high cholesterol).

The FDA has banned the sale of red yeast rice products containing lovastatin, stating that such products "may contain an unauthorized drug that could be harmful to health." Although some dietary supplements contain lovastatin-free red yeast rice, little is known about the effectiveness of these supplements in lowering cholesterol levels.

What Are the Side Effects of Red Yeast Rice?

The lovastatin found in some red yeast rice products may trigger a number of side effects, including severe muscle pain, muscle damage, and kidney and liver damage. There's also some concern that lovastatin-free red yeast rice may cause similar side effects.

When improperly fermented, red yeast rice may contain citrinin (a poisonous substance that may lead to kidney damage).

What's more, red yeast rice may cause mild side effects like headaches, heartburn, and upset stomach.

Research on Red Yeast Rice & Its Side Effects

In a report published in the journal Pharmacy and Therapeutics in 2009, researchers reviewed a number of published case reports showing potential side effects associated with the use of red yeast rice.

These case reports included incidences of myopathy, which is a type of neuromuscular disorder in which the primary symptom is muscle weakness due to dysfunction of muscle fiber.

In the 2009 report, red yeast rice was also linked to the development of a condition called rhabdomyolysis. In rhabdomyolysis, a breakdown of muscle tissue leads to the release of muscle fiber contents into the blood. Harmful to the kidney, these muscle-fiber contents can cause kidney damage.

In conclusion, the authors of the 2009 report stated that "red yeast rice products can be beneficial in lowering serum cholesterol levels, but they are not without risk." Furthermore, the authors added, "product uniformity, purity, labeling, and safety cannot be guaranteed" when it comes to red yeast rice supplements.

Side Effects and Safety

Red yeast rice is possibly safe for most people when taken by mouth for up to 4 1/2 years, according to the National Institutes of Health (NIH). However, the NIH also states that red yeast rice is likely unsafe for use during pregnancy. In tests on animals, red yeast rice has been found to cause birth defects.

Given the possible health risks associated with the use of red yeast rice, it's important to consult a physician if you're thinking of using this supplement for any purpose.

Alternatives to Red Yeast Rice

Red yeast rice is just one of many natural remedies touted as an alternative approach to keeping cholesterol in check. For example, some research suggests that herbs like herbs like garlic and guggul may help curb cholesterol levels as well.

In addition, there's some evidence that drinking green tea on a regular basis, increasing your soy intake, getting your fill of omega-3 fatty acids, and consuming plant sterols may aid in cholesterol management.

Like red yeast rice, these alternative remedies may also cause certain side effects. Given the health risks, it would be wise to avoid red yeast rice products. To protect against the potentially adverse effects of any type of dietary supplement, learn more about using supplements safely but be sure to talk with your doctor if you're considering using supplements.

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Article Sources
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  1. National Center for Complementary and Integrative Health. Red yeast rice. Updated March 19, 2018.

  2. Farkouh A, Baumgärtel C. Mini-review: medication safety of red yeast rice products. Int J Gen Med. 2019;12:167-171. doi:10.2147/IJGM.S202446

  3. Mount Sinai. Red yeast rice.

  4. Klimek M, Wang S, Ogunkanmi A. Safety and efficacy of red yeast rice (Monascus purpureus) as an alternative therapy for hyperlipidemia. PT. 2009;34(6):313-27. 

  5. Houston M. The role of nutraceutical supplements in the treatment of dyslipidemia. J Clin Hypertens (Greenwich). 2012;14(2):121-32. doi:10.1111/j.1751-7176.2011.00576.x

Additional Reading
  • Klimek M, Wang S, Ogunkanmi A. "Safety and efficacy of red yeast rice (Monascus purpureus) as an alternative therapy for hyperlipidemia." P T. 2009 Jun;34(6):313-27.
  • National Institutes of Health. "Red yeast: MedlinePlus Supplements." February 2015.
  • U.S. Food and Drug Administration. "FDA Warns Consumers to Avoid Red Yeast Rice Products Promoted on Internet as Treatments for High Cholesterol." August 2007.
  • Yang CW, Mousa SA. "The effect of red yeast rice (Monascus purpureus) in dyslipidemia and other disorders." Complement Ther Med. 2012 Dec;20(6):466-74.