Turning Red: Variability in RYR Products

Abstract & Commentary

By Russell H. Greenfield, MD, Editor

Source: Gordon RY, Cooperman T, Obermeyer W, Becker DJ. Marked variability of monacolin levels in commercial red yeast rice products. Arch Intern Med 2010;170:1722-1727.

Synopsis: A mixture of monacolins is the primary candidate for the active participle of red yeast rice, (RYR) an over-the-counter remedy frequently used to help control elevated cholesterol levels. This study reveals wide variations in the monacolin content of a sample of red yeast products that may significantly impact therapeutic response, as well as the presence in some of potentially toxic contaminants.

The authors behind this investigation determined monacolin levels in a sample of 12 commercial RYR formulations and tested for the presence of citrinin (CN), a mycotoxin known to cause renal damage in animals. Twelve commercial RYR products, which the authors state were representative of commonly sold formulations available in the United States, were purchased and sent for analysis by an independent testing organization. Products were bought online from retailers, catalogs, multilevel marketing companies, or directly from the manufacturer. Two of the formulations had been tested earlier in association with their use in clinical trials. The remaining 10 products were tested in 2008 as part of a product review of RYR supplements published by the online subscription service ConsumerLab.com. A single lot for each product was tested for content of specific monacolins, disintegration, and for contaminants, specifically CN and lead.

Results showed significant variability between the various products with respect to total monacolin content, monacolin K (MK, frequently referred to as lovastatin), and the hydroxy form of MK. Four of the 12 products contained elevated levels of CN. None of the products, however, contained lead in excess of contamination limits, and all were found to disintegrate properly.

The authors conclude that dramatic variation exists between RYR products and their content of potentially active ingredients. In addition, a significant number of RYR products on the market have the potential to harm people taking them due to the presence of CN.


RYR has been used in Asia for centuries as a medicinal agent and food colorant, and is produced by culturing the yeast Monascus purpureus on rice. The process creates monacolins, a group of compounds that inhibit hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase, the enzyme you will likely recognize as the conventional prime target for the therapeutic reduction of hepatic cholesterol synthesis. Monacolin K, or MK, is marketed as lovastatin; therein lies a significant rub, as the Food and Drug Administration (FDA) typically considers RYR a dietary supplement, but when the monacolin content of RYR is standardized it may be considered a drug. Such was the genesis of FDA action against a number of companies selling RYR in recent years.

RYR remains on the shelves of many pharmacies and health food stores, and it is easily obtained over the Internet. Interest in its use among the population with high cholesterol has soared. Studies suggest that well-formulated RYR products can effectively lower cholesterol levels, and apparently with somewhat lower risk for liver and muscle dysfunction than statin drugs. Research results point to RYR also being a viable option for people with high cholesterol who are intolerant of statin therapy.1

But the results of this paper suggest a real problem— the lack of standardization of monacolin content across products. In fact, there having been only one lot tested from each manufacturer, it is possible that batch-to-batch variability also exists in this regard. On the other hand, as the authors note, the majority of the work done for this investigation took place before many companies phased in the Good Manufacturing Practices (GMPs) recently mandated for supplement manufacturers. The question of the presence of CN in some products raises another red flag that hopefully has been addressed through the GMPs, but we cannot yet know this for certain.

The precautionary tale woven throughout this article is not without its own shortcomings. For example, the authors state the products chosen were representative of those widely available in the marketplace but we are left to take their word for that, even though no products were purchased directly off store shelves. Nor do we know why the specific number (12) of products was chosen. To the authors' credit, they point out another limitation of their investigation is that it remains unknown whether there might be active ingredients apart from monacolins in RYR products.

Although the supplement industry seems to be cleaning up its act, there is still reason for a "buyer beware" mentality, as evidenced by the data presented here. Should a person be using RYR and not experience a significant therapeutic response, the knee-jerk reaction might be that RYR is not effective, when in fact the product may not contain sufficient active ingredients. Wherever possible, it is important to point our patients in the direction of companies who adhere to the GMPs now in place to best ensure safety and clinical effectiveness for any and all supplement use.


1. Becker DJ, Gordon RY, Halbert SC, et al. Red yeast rice for dyslipidemia in statin-intolerant patients: A randomized trial. Ann Intern Med 2009;150:830-839.