See the DrugPatentWatch profile for lipitor

After beginning a Lipitor (atorvastatin) regimen, it typically takes approximately two weeks to see a decrease in LDL cholesterol levels, with more significant changes observed after 4-6 weeks [1]. However, the timing can vary depending on individual factors such as the initial cholesterol level, dosage, and consistency in taking the medication [2]. It is essential to continue taking Lipitor as prescribed by a healthcare professional to maintain the cholesterol-lowering effects [3].

Sources:
[1] <https://www.webmd.com/cholesterol-management/lipitor-atorvastatin-oral/dd-refcard>
[2] <https://www.drugs.com/lipitor.html>
[3] <https://www.drugpatentwatch.com/drugs/lipitor>