How Long Does It Take for Red Yeast Rice to Lower Cholesterol?

Red yeast rice dietary supplements work if they contain lots of a chemical called monacolin K. The red yeast rice dietary supplements available in the U.S. contain very little monacolin K because of FDA rules, however, and may as a result have little or no effect on blood cholesterol levels.

Red yeast rice is produced by cultivating the yeast species Monascus purpureus on rice. It is often touted as a natural treatment to reduce low-density lipoprotein (LDL) cholesterol (“bad” cholesterol). 

How Does Red Yeast Rice Work to Lower Cholesterol? 

Red yeast rice naturally contains monacolin K, a compound similar to lovastatin. Lovastatin is an HMG-CoA reductase inhibitor (a statin drug), a type of drug commonly used to treat high cholesterol. 

Red yeast rice also contains:

• Sterols: plant-based substances known to lower cholesterol
• Isoflavones: substances that are considered phytoestrogens and anti-oxidant compounds
• Monounsaturated fatty acids: “good” fats that can help reduce cholesterol

The recommended dose of red yeast rice is 1,200 mg taken orally twice daily with food. In studies, patients started to see a reduction in cholesterol levels at about 12 weeks. 

However, in all the studies that showed red yeast rice helped lower cholesterol, all the products studied contained substantial amounts of monacolin K. The U.S. Food and Drug Administration (FDA) considers monacolin K to be a pharmaceutical product, and has concluded that red yeast rice products that contain more than trace amounts of monacolin K are considered unapproved new drugs and cannot be sold legally as dietary supplements. Thus, the red yeast rice dietary supplements available in the U.S. contain very little monacolin K and may have little or no effect on blood cholesterol levels.

Side effects of red yeast rice include:

• Abdominal discomfort
• Stomach upset
• Heartburn
• Dizziness
• Headaches
• Elevated creatine kinase
• Elevated liver enzymes
• Gas (flatulence)
• Constipation
• Severe allergic reaction (anaphylaxis) with inhalation

Red yeast rice is often marketed as a natural supplement; however, its use can carry risks: 

• May cause muscle, liver, and kidney problems similar to those caused by statins
  • Should not be used by people who have liver or kidney disease
• Red yeast rice products should not be used by women who are pregnant or breastfeeding 
• Red yeast rice products should not be used in patients who take prescription statin drugs 
• Because it’s a supplement, the contents of red yeast rice products are not standardized, making it impossible to know the quantity or quality of the ingredients 
  • Most products state only the amount of red yeast rice on the label, and not the amount of monacolin K, which is what can help lower cholesterol
  • Some red yeast rice products have been found to contain citrinin, a contaminant that can cause kidney failure
  • In the past, the FDA has warned consumers to avoid red yeast rice products promoted on the internet as treatments for high cholesterol because some contained lovastatin, a prescription medication
    • Lovastatin can have adverse interactions with other medications such as the antidepressant nefazodone, certain antibiotics, drugs used to treat fungal infections and HIV infections, and other cholesterol-lowering medications
• Red yeast rice may interact with many medications, including:
  • Statin drugs
  • Other cholesterol drugs 
  • Immunosuppressant drugs such as cyclosporine
  • Antifungals
  • Macrolide antibiotics
  • Protease inhibitors used to treat HIV
  • Grapefruit
  • Lanthanum carbonate
  • Maraviroc
  • St. John's wort