Recent tests of 11 red yeast rice supplements revealed enormous differences in levels of cholesterol-lowering statin compounds, according to ConsumerLab.com, White Plains, NY. Statin levels fell dramatically among brands previously tested in 2008 and a potentially toxic contaminant, citrinin, was found in four of the products.

Red yeast rice naturally contains the cholesterol-lowering statin compound lovastatin, the active ingredient in prescription Mevacor. Labels on red yeast rice products, however, generally do not disclose lovastatin content due to concern that the supplement will be considered an unapproved drug by FDA and removed from the market. This makes it difficult for consumers and doctors to assess and compare red yeast rice supplements, although they remain widely used and can be effective.

Clinical studies of red yeast rice have shown reductions in LDL cholesterol of 18% to 42%, although each study has used a different red yeast rice preparation. In addition to containing lovastatin, red yeast rice contains a variety of related compounds, which may act synergistically to lower LDL cholesterol. Side effects may also be diminished compared to pharmaceutical statins.

Among 11 products in the report, amounts of lovastatin compounds ranged from 0 mg to 3.5 mg per 600 mg of red yeast rice. The average amount was 1.48 mg per 600 mg. Products shown to work clinically have contained 1.63 mg to 5.7 mg of lovastatin compounds per 600 mg of red yeast rice. Based on the suggested serving sizes of the recently tested products, ConsumerLab.com found that only four would deliver a daily dose of lovastatins in the range used in clinical studies.

Several products in the current review were among those previously reviewed by ConsumerLab.com in 2008 (and subsequently published in a peer-reviewed article in Archives of Internal Medicine in 2010). ConsumerLab.com discovered the amounts of lovastatin compounds in these products to be 29% to 88% lower than in the same ones purchased in 2008, although the labeled amount of red yeast rice (600 mg) remained the same. The declines suggest that different and chemically weaker red yeast rice raw materials are now being used.

“Red yeast rice can be one of the most effective supplements but one of the most difficult for choosing a brand because companies can’t list amounts of active ingredients on their labels,” said Tod Cooperman, MD, president of ConsumerLab.com. “Making matters worse, after relying on a particular brand, it may change dramatically without warning, possibly leaving you and your doctor wondering why your cholesterol levels have changed. If you use or are considering using red yeast rice, our findings may be very helpful.”

Commenting on the dramatic differences among brands over time, William Obermeyer, PhD, vice president for research at ConsumerLab.com, said, “The compounds found in red yeast rice can vary based on the yeast strain and growth conditions. Cultures can also change chemical composition over time, which is why manufacturers should test each lot to help ensure a consistent product. It is also possible that some manufacturers intentionally switched to suppliers of red yeast rice with less lovastatin to try to avoid issues with the FDA.”