Overview

Red yeast rice is available over the counter as a dietary supplement, usually as a tablet, capsule, or powder. It is commonly used for high cholesterol, although its effects vary depending on which product you use. Common side effects may include headache, muscle spasms or pain, constipation, diarrhea, or stomach pain. Serious side effects are rare but can include liver damage and muscle problems. Red yeast rice may interact with many medicines. Before taking red yeast rice, make sure to tell your health care provider about any health conditions you have or medicines you are taking.

Uses

What is red yeast rice used for?

Red yeast rice is commonly used for high cholesterol. However, the benefits of specific red yeast rice products are not well defined.

Note: The FDA has not reviewed red yeast rice for safety and effectiveness. Learn more about dietary supplements here.

How does red yeast rice work (mechanism of action)?

Red yeast rice is formed when a certain type of mold (Monascus purpureus) grows and ferments on rice. The mold causes the rice to turn red, leading to its name.

Red yeast rice contains a group of chemicals called monacolins. One of these chemicals, monacolin K, has the same chemical structure as the prescription medicine, lovastatin. Lovastatin is a type of medicine called a statin, which is used to lower cholesterol levels in people with high cholesterol. It works by decreasing the amount of cholesterol made by the liver and increasing the breakdown of bad cholesterol.

Although monacolin K can lower cholesterol levels, it is not always clear how much of this chemical is present in red yeast rice. The amount of each chemical in red yeast rice naturally varies. This means that the amount of monacolin K in red yeast rice products also varies. If a product only contains small amounts of monacolin K, it may not have any effects on cholesterol. If a product contains high amounts of monacolin K, it may help to lower cholesterol but may also cause side effects. The FDA has sent warnings to companies that make products with high amounts of monacolin K. These products are not allowed to be sold as dietary supplements because they contain a prescription medicine.

How should I store red yeast rice?

You should store red yeast rice according to the product label. Most dietary supplements should be kept in a cool, dry location that is out of the reach of children and pets and not in direct sunlight.

Side Effects

What are the most common side effects of red yeast rice?

The most common side effects of red yeast rice are listed below. These side effects may vary depending on the dose you are taking or the specific product you are using. Tell your health care provider if you have any of these side effects that bother you.

• Headache
• Muscle spasms or pain
• Constipation
• Diarrhea
• Upset stomach

There may be other side effects of red yeast rice that are not listed here. Contact your health care provider if you think you are having a side effect of a supplement. In the U.S., you can report side effects to the FDA at www.safetyreporting.hhs.gov or by calling 888-SAFEFOOD (888-723-3366). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of red yeast rice?

While less common, the most serious side effects of red yeast rice are described below, along with what to do if they happen.

Severe Allergic Reactions. Red yeast rice may cause allergic reactions, which can be serious. Stop taking red yeast rice and get help right away if you have any of the following symptoms of a serious allergic reaction.

• Breathing problems or wheezing
• Racing heart
• Fever or general ill feeling
• Swollen lymph nodes
• Swelling of the face, lips, mouth, tongue, or throat
• Trouble swallowing or throat tightness
• Itching or skin rash
• Bumps on the skin called hives that can be red, pink, white, or brown depending on your skin tone
• Nausea or vomiting
• Dizziness, feeling lightheaded, or fainting
• Stomach cramps
• Joint pain

Muscle Problems.Red yeast rice can cause muscle problems, including muscle pain, weakness, and tenderness, called myopathy. In some people, the muscle may break down (rhabdomyolysis), which can be serious and rarely lead to kidney damage and death. Stop taking red yeast rice and get help right away if you have any of the following symptoms of myopathy or rhabdomyolysis.

• Unexplained muscle pain, weakness, or tenderness
• Low energy levels or feeling easily tired, especially with activity
• Dark-colored urine (pee)
• Fever
• Muscle cramps
• Stomach pain
• Nausea or vomiting

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking red yeast rice. Call your health care provider right away if you have any of the following symptoms of liver damage.

• Nausea or vomiting
• Stomach or belly pain
• Fever
• Weakness or unusual tiredness
• Itching
• Loss of appetite
• Light-colored poop
• Dark-colored urine (pee)
• Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Increased Blood Sugar. Red yeast rice can sometimes increase blood sugar (glucose), which is called hyperglycemia. Talk to your health care provider about how to maintain healthy blood sugar levels.

Precautions

Who should not use red yeast rice?

Allergies to Ingredients. People who are allergic to any of the following should not take red yeast rice.

• Lovastatin
• Red yeast rice (RYR)
• Red yeast rice extract (RYRE)
• Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific red yeast rice products they stock.

Liver Problems. You should not take red yeast rice if you have liver problems. Red yeast rice can damage the liver and make liver problems worse.

Drug Interactions. Red yeast rice should not be taken while you are using certain medicines. Before taking red yeast rice, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about red yeast rice before using it?

Red yeast rice is a dietary supplement. It cannot be marketed to treat or cure a disease.

Read and follow the directions on the specific product you are taking, or take it as recommended by your health care provider.

Keep red yeast rice out of the reach of children.

People who are 65 or older can be at greater risk of some side effects from red yeast rice, including muscle pain, weakness, and injury. Talk to your health care provider about your risks if you are in this age group.

Herbal products, such as red yeast rice, naturally contain many different chemicals. The amount of each chemical in a specific red yeast rice product can vary for many reasons, including the amount of mold growing on the rice, how long the mold fermented on the rice, and how the rice was processed. If you switch to a new bottle or a different brand, you may not have the same effects or side effects because of this variability. Talk to your health care provider if you have questions or concerns.

The FDA has not tested red yeast rice products to confirm that they contain the ingredients stated on their labels. Some dietary supplements have been tested by third-party organizations to confirm that they contain the ingredients listed on their labels and do not contain any harmful chemicals. Learn more about how to choose a safe dietary supplement product here.

Some red yeast products contain a toxin called citrinin, which can cause serious side effects, such as kidney damage. This toxin can be created when red yeast rice is processed in certain ways. Some red yeast rice products are certified citrinin-free. It is important to read the label carefully to make sure the product has been tested for citrinin.

What should I tell my health care provider before using red yeast rice?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if red yeast rice is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

• Diabetes
• Muscle weakness or pain that cannot be explained
• Kidney problems
• Liver problems
• Drink large amounts of alcohol

Pregnancy. Red yeast rice may cause harm to an unborn baby. Tell your health care provider if you are or plan to become pregnant. If you become pregnant, stop taking red yeast rice right away and contact your health care provider.

Breastfeeding. Do not take red yeast rice while you are breastfeeding. It is not known if red yeast rice passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed.

Interactions

Does red yeast rice interact with foods or drinks?

Do not drink large amounts of grapefruit juice while taking red yeast rice. Grapefruit juice can make red yeast rice stay in your body longer, which can increase the levels in your body. This may increase the risk of side effects, such as muscle pain and damage, from red yeast rice. See the Side Effects section for more details.

Limit the amount of alcohol you drink while taking red yeast rice. Drinking significant amounts of alcohol while taking red yeast rice may increase your risk of liver damage.

Does red yeast rice interact with medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking red yeast rice.

• A medicine for HIV, AIDS, or hepatitis C
• Amiodarone, dronedarone, diltiazem, verapamil, and ranolazine, which is a medicine used for certain heart conditions
• Clarithromycin or erythromycin, which is a medicine used for bacterial infections
• Colchicine, which is a medicine commonly used for gout
• Cyclosporine (Gengraf, Neoral, Sandimmune, and others), which is a medicine that suppresses your immune system
• Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
• Itraconazole (Sporanox, Tolsura), ketoconazole, posaconazole (Noxafil), or voriconazole (Vfend), which is a medicine used for fungal infections
• Niacin or a fibrate, such as fenofibrate (Tricor), fenofibric acid (Fibricor, Trilipix), or gemfibrozil (Lopid), which is a medicine for high cholesterol

Some other medicines may alter the blood levels of red yeast rice, and vice versa.

The interactions between red yeast rice and medicines are not fully understood. As with most dietary supplements, the research on drug interactions with red yeast rice is incomplete. Always check with your health care provider before taking red yeast rice with any medicines.

Dosing

What should I do if I accidentally use too much red yeast rice?

If you or someone else has used too much red yeast rice, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

Red yeast rice products may contain very different amounts of certain chemicals. This can change the effects of red yeast rice in the body. Read the product label closely and speak with a health care provider about how to take red yeast rice safely. Do not take double or extra doses, even if you miss a dose.