Background and Rationale Statins, HMG-CoA reductase inhibitors are generally safe; however, myalgia (e.g., pain, cramping, muscle soreness and/or weakness) occurs in about 5% of users iii,iv and can seriously impact quality of life and adherence to statin medications. Furthermore, there are no objective, non-invasive method for assessing and tracking mild-moderate muscle symptoms, which are most common and often occur without significant muscle enzyme "CK" elevation. Muscle biopsy is used to assess severe myopathy and has been used to evaluate statin myalgia without CK elevation, but is invasive, painful, and provides only a single time point measurement.