Lipitor is a brand name for the drug atorvastatin, which is used to lower cholesterol levels in the body. According to the sources provided, it may take several weeks to see the full effects of Lipitor.

DrugPatentWatch [1] notes that the patent for Lipitor expired in 2011, meaning that generic versions of the drug are now available. The website provides information on the drug's chemical makeup, as well as its indications and dosages.

Drugwatch [2] explains that Lipitor works by inhibiting an enzyme in the liver that produces cholesterol. This results in lower levels of LDL, or "bad" cholesterol, in the bloodstream. The website notes that it may take several weeks to see a significant reduction in cholesterol levels after starting Lipitor.

Healthline [3] provides similar information, noting that it may take up to four weeks to see the full effects of Lipitor. The website also explains that Lipitor is typically taken once a day, with or without food.

In conclusion, while the sources do not provide an exact timeline for when Lipitor starts working, they suggest that it may take several weeks to see significant results. It is important to follow the prescribed dosage and to continue taking the medication as directed by a healthcare provider.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.drugwatch.com/lipitor/
[3] https://www.healthline.com/health/drugs/lipitor