2.1 Red Yeast Rice Monascus purpureus is a mold that ferments rice to produce Red Yeast Rice (RYR), which is red and contains molecules that inhibit hepatic cholesterol synthesis. Between 70–83% of these molecules actually are monacolin K, both as lactone (K) and open-ring acid (Ka). Unbeknownst to the lay public, monacolin K is identical to the statin lovastatin and, thus, inhibits HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis. For largely unexplored reasons (possibly a matrix efect), RYR monacolins are more bioavailable than pure lovastatin; therefore, their efcacy on cholesterol concentrations is greater than that of lovastatin, on a mg-per mg-basis