This is a prospective, placebo-controlled, cross-over trial comparing the the effects of approximately 7 weeks of placebo treatment to 7 weeks of ezetimibe (10mg/day) treatment on several parameters of reverse cholesterol transport (RCT) in men and post-menopausal women diagnosed with hypercholesterolemia. The primary hypothesis is that the ezetimibe treatment will increase the excretion of endogenous (plasma-derived) cholesterol as fecal sterols, with secondary hypotheses that there will be a significant increase in de novo cholesterol synthesis, treatment will increase cholesterol efflux from tissues into the bloodstream, and increase global RCT.

The study will compare the effects of approximately 7 weeks of placebo treatment to 7 weeks of ezetimibe (10mg/day) on: 1) the efficiency of endogenous (plasma-derived) cholesterol excretion (%/day) 2) de novo cholesterol (DNC) synthesis ((%/day) 3) cholesterol efflux from tissues into blood (Ra), and 4) global RCT (efflux from tissues that is excreted as fecal sterols). Subjects will receive 7 weeks of either treatment or placebo, undergo RCT and DNC measurements, taking 10 days, then cross-over to the alternate placebo or treatment for an additional 7 weeks, followed by a second set of RCT and DNC measurements.

Inclusion Criteria:

• male, non-smoker, 21-75 years of age
• female, non-smoker, 40-75 years of age
• post-menopausal women, as defined by lack of menses for at least 2 years and age >55, OR history of documented bilateral oophorectomy, confirmed with an elevated FSH at screening
• low-density lipoprotein (LDL) concentration between 130-200 mg/dL.
• triglyceride (TG) concentration <350 mg/dL, inclusive
• high-density lipoprotein (HDL) between 30-60 mg/dL for men and 40 -70 mg/dL for women
• ability to give informed consent

Exclusion Criteria:

• Subject has history of diabetes mellitus, active hepatitis, gall bladder disease, gastric or ileal bypass surgery, irritable bowel syndrome, and gastrointestinal disorder/condition associated with malabsorption, or clinically significant abnormalities on screening (prestudy) physical examination of laboratory tests.
• Screening laboratory tests with hematocrit <30%, aspartate aminotransferase/alanine aminotransferase (AST/ALT) >2*upper limit of normal, abnormal thyroid-stimulating hormone (TSH), fasting glucose >=126mg/dL
• renal impairment with creatinine clearance (CRCl)<80ml/min
• treatment within the last 2 months with drugs known to alter lipid metabolism including beta blockers, thiazide diuretics, bile acid resins, statins, ezetimibe, niacin, fibrates, plant stanol esters (eg Benecol,phyto sterols) and fishoils
• history of known coronary heart disease (CHD), stroke or prior revascularization procedure or peripheral vascular disease
• history of allergy to egg or soy products
• current or recent (past 12 months) of drug abuse or alcohol abuse. Alcohol use must be limited to no more than 2 drinks/day (1 drink=12 oz beer, 5 oz wine, or 1.5 oz hard liquor). Subject must be willing to avoid large day-to-day fluctuations in alcohol intake.
• participation in another clinical trial or exposure to any investigational agent within 30 days prior to Visit 1
• Individual has a condition the Principal Investigator believes would interfere with his/her ability to provide informed consent, comply with study instructions, or which might confound the interpretation of the study results, or put the subject at undue risk

7 weeks