Lipitor is a medication used to lower cholesterol levels in the body, particularly low-density lipoprotein (LDL) cholesterol. According to a study published in the American Heart Association journal [2], it takes about two weeks for Lipitor to reduce LDL cholesterol levels. The study found that patients who took Lipitor experienced a significant reduction in LDL cholesterol levels after two weeks of treatment. However, the study also noted that the maximum effect of Lipitor on LDL cholesterol levels may take up to four weeks to achieve.

WebMD [3] also notes that the effectiveness of Lipitor in reducing LDL cholesterol levels varies from person to person and depends on various factors such as the initial cholesterol level, dosage, and overall health. In some cases, it may take longer for Lipitor to reduce LDL cholesterol levels. Patients should continue to take the medication as prescribed and follow up with their healthcare provider regularly to monitor their cholesterol levels.

It is worth noting that the duration of Lipitor's effectiveness in reducing LDL cholesterol levels may vary depending on the individual's adherence to a healthy lifestyle, including a healthy diet and regular exercise. Patients should consult with their healthcare provider to develop a comprehensive plan to manage their cholesterol levels.

Sources:
[2] https://www.ahajournals.org/doi/full/10.1161/01.atv.15.5.678
[3] https://www.webmd.com/cholesterol-management/features/when-your-doctor-orders-cholesterol-lowering-medications
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR