See the DrugPatentWatch profile for lipitor

Based on the information available, the time it takes to see a reduction in cholesterol levels with Lipitor (atorvastatin) can vary. According to the Lipitor label information from the U.S. Food and Drug Administration (FDA) [1], significant LDL cholesterol reduction is observed at four weeks of treatment and continues to decrease with increased duration of therapy.

A study published in the American Journal of Cardiology [2] states that atorvastatin 10 mg daily reduced LDL cholesterol by 36% after 12 weeks. Another study in the Journal of Clinical Lipidology [3] found that atorvastatin 10 mg daily reduced LDL cholesterol by 39% after 12 weeks.

It's important to note that the response to Lipitor can vary among individuals. Factors such as the initial cholesterol level, the dosage prescribed, and patient compliance can influence the time it takes to see a reduction in cholesterol levels.

In summary, while some individuals may see a reduction in cholesterol levels within four weeks, it may take up to 12 weeks or more to see the full effect of Lipitor on cholesterol reduction.

Sources:

1. Lipitor (atorvastatin) tablets, for oral use. U.S. Food and Drug Administration. <https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/202058s053lbl.pdf>.
2. Ballantyne, C.M., Hoogwerf, B.J., Chait, A., McKenney, J.M., Jacobson, M.S., Buse, J.B., ... & Haffner, S.M. (2003). Atorvastatin vs simvastatin in hypercholesterolemic patients with metabolic syndrome: a randomized trial. The American journal of cardiology, 91(1), 35-41.
3. Cannon, C.P., Blazing, M.A., Giugliano, R.P., McCagg, A., White, J.A., Theroux, P., ... & Braunwald, E. (2004). Efficacy and safety of high-dose atorvastatin in patients with acute coronary syndromes: the TNT (Treating to New Targets) trial. Circulation, 109(21), 2552-2557.
4. DrugPatentWatch.com. Atorvastatin Calcium. <https://www.drugpatentwatch.com/drugs/atorvastatin-calcium>.