Monacolin K supplementation in patients with hypercholesterolemia: A systematic review of clinical trials

Monacolin K is the major active component in red yeast rice (RYR) which is structurally identical to lovastatin and has the most powerful effect, in terms of reducing blood cholesterol levels. This review aimed to examine the effect and safety of different doses of monacolin K on blood cholesterol levels. PubMed and Cochrane were searched for articles published between 2012 and 2023 for clinical-trials and randomized-controlled-trials. Eligible studies included participants > 18-years-old, of any gender and ethnicity. The intervention/exposure of interest was monacolin K. Hypercholesterolemia was considered the outcome of interest defined as the elevated total or low-density-lipoprotein (LDL) cholesterol levels. 12 randomized-controlled-trials were eligible for inclusion in the analysis including 769 participants > 18-years-old. 11 out of 12 studies were assessed with high methodological quality and one study with low methodological quality. Monacolin K supplementation varied between 2 mg and 10 mg per day and the maximum period of supplementation was 12 weeks. All studies indicated a beneficial effect of monacolin supplementation on LDL and total cholesterol levels (p < 0.05) regardless the dose and period of supplementation. Also, 3 of the included studies reported adverse side effects after treatment with monacolin K. Low doses of monacolin K equal to 3 mg/day exert potential cholesterol-lowering effects although the number of relative studies is limited. Regarding the safety of monacolin K supplementation, findings seem to be more controversial and therefore, it is suggested for all patients treated with monacolin K to be routinely monitored regardless the dose of supplementation.