Lipitor, also known as atorvastatin, is a medication used to lower cholesterol levels in the blood. According to Drug Patent Watch [1], Lipitor is a widely prescribed medication, and it is the best-selling drug in the world. The drug works by inhibiting an enzyme called HMG-CoA reductase, which is involved in the production of cholesterol in the liver. By reducing the production of cholesterol, Lipitor can lower the levels of LDL cholesterol, also known as "bad" cholesterol, in the blood.

Several studies have examined the effectiveness of Lipitor in reducing cholesterol levels. A study published in the Arteriosclerosis, Thrombosis, and Vascular Biology journal [2] found that Lipitor was effective in reducing LDL cholesterol levels in patients with hypercholesterolemia. The study also found that Lipitor was well-tolerated by patients, with few adverse effects reported.

Another study published in the National Center for Biotechnology Information [3] reported that Lipitor was effective in reducing LDL cholesterol levels in patients with type 2 diabetes. The study found that Lipitor reduced LDL cholesterol levels by an average of 39%, and also reduced the risk of cardiovascular events in these patients.

Overall, the available evidence suggests that Lipitor is an effective medication for reducing cholesterol levels, particularly LDL cholesterol. However, as with any medication, Lipitor may not be effective for everyone, and individual responses to the medication may vary. It is important to discuss the risks and benefits of Lipitor with a healthcare provider before starting treatment.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ahajournals.org/doi/full/10.1161/01.atv.15.5.678
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6464917/