Lipitor is a medication used to lower cholesterol levels and prevent heart disease. According to Drug Patent Watch [1], Lipitor's active ingredient is atorvastatin calcium. This drug works by blocking the production of cholesterol in the liver, which can help to reduce the risk of heart attack and stroke. However, some studies suggest that Lipitor may have negative effects on muscle building progress.

A study published in the Journal of Clinical Endocrinology and Metabolism [2] found that taking statins, including Lipitor, can decrease muscle strength and mass. The study also showed that statin use can reduce the production of testosterone, which is essential for muscle growth. Another study published in the Journal of the American College of Cardiology [3] found that statin use can cause muscle damage, particularly in people who exercise regularly.

Despite these findings, the Mayo Clinic [4] notes that there is no definitive evidence that Lipitor directly affects muscle building progress. However, the clinic does recommend that people who take Lipitor or other statins should be aware of the potential risks and talk to their doctor about any concerns they may have.

In conclusion, while there is some evidence to suggest that Lipitor may have negative effects on muscle building progress, there is no definitive proof. People who take Lipitor or other statins should be aware of the potential risks and talk to their doctor about any concerns they may have.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2949584/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3117170/
[4] https://www.mayoclinic.org/drugs-supplements/amlodipine-and-atorvastatin-oral-route/precautions/drg-20062902