Lipitor is a brand name for atorvastatin, a medication used to lower cholesterol levels in the blood. According to the NHS, atorvastatin is usually taken once a day, with or without food, at any time of the day [2]. However, some studies suggest that taking atorvastatin at night may be more effective in reducing cholesterol levels. Drugs.com explains that atorvastatin is best taken at night because the body produces more cholesterol during the night than during the day, and atorvastatin works by blocking the production of cholesterol in the liver [3]. It is important to follow the instructions provided by your doctor or pharmacist when taking Lipitor, as the dosage and timing may vary depending on individual needs and medical conditions. As with any medication, it is essential to consult with a healthcare professional before starting or changing the dosage of Lipitor.

Sources:
[2] https://www.nhs.uk/medicines/atorvastatin/how-and-when-to-take-atorvastatin/
[3] https://www.drugs.com/medical-answers/does-lipitor-work-better-if-you-take-it-at-night-416127/
[4] https://www.drugpatentwatch.com/p/tradename/LIPITOR