Safety and side effects

Red yeast rice can cause mild side effects, including:

• Abdominal discomfort
• Heartburn
• Gas
• Headache
• Dizziness

Red yeast rice might contain monacolin K, the same ingredient that is in the prescription cholesterol-lowering drug lovastatin. Lovastatin side effects include liver damage and muscle disorders (myopathy).

Don't take red yeast rice if you're pregnant, trying to become pregnant or breast-feeding.

An older study raised the concern that some red yeast rice products contain a contaminant called citrinin, which can cause kidney failure. However, a more recent study that analyzed 14 red yeast rice dietary supplements didn't find citrinin in any of them.