Lipitor is a brand name for the drug atorvastatin, which is a type of medication used to lower cholesterol levels in the blood. According to WebMD [2], it may take several weeks to months for Lipitor to show significant results in lowering cholesterol levels. It is important to take Lipitor as prescribed by a doctor and to continue taking it even if you do not see immediate results.

The British Heart Foundation [3] also notes that it may take several weeks for statins, including Lipitor, to show results in reducing cholesterol levels. The foundation advises patients to continue taking the medication as prescribed and to have their cholesterol levels checked regularly to monitor progress.

Drug Patent Watch [1] provides information on the patent expiration of Lipitor, but does not provide information on how long it takes for the drug to show results.

In summary, both WebMD and the British Heart Foundation suggest that it may take several weeks to months for Lipitor to show significant results in lowering cholesterol levels. It is important to follow a doctor's instructions and to continue taking the medication as prescribed.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.webmd.com/cholesterol-management/features/when-your-doctor-orders-cholesterol-lowering-medications
[3] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/drug-cabinet/statins