Dear Colleagues --
Recently the attached paper was published regarding variability in strength of red yeast rice supplements purchased from mainstream retailers -- these retailers being GNC, Walgreens, Wal Mart and Whole Foods.
The authors are Pieter Cohen, Bharathi Avula, and our colleague, Ikhlas Khan. This study has received limited attention in the U.S., likely due to this being a European journal, which, itself, is somewhat unusual that a European journal would report on findings from products primarily sold in the U.S.
Notwithstanding, the results are sobering. The strength (potency) in the 28 brands tested ranged from 60 fold, when measured against dosage weights, and 120 fold, when based on recommended daily serving. No brands are mentioned.
As the authors point out, even though there are dietary supplement GMPs, the variability in product strength/potency remains variable.