Lipitor, the brand name for atorvastatin, is a medication used to lower cholesterol levels and reduce the risk of heart disease. The effectiveness timeline of Lipitor varies depending on the individual and their specific condition.

According to Drug Patent Watch [1], the patent for Lipitor expired in 2011, which means that the medication has been available in generic form since then. However, the effectiveness of Lipitor and its generic counterparts has been extensively studied and documented.

A study published in the National Library of Medicine [2] found that atorvastatin can lower cholesterol levels within two weeks of starting treatment. The study also found that the maximum effect of the medication is usually achieved within four to six weeks of starting treatment.

Wikipedia [3] notes that the effectiveness of atorvastatin can also depend on the dosage prescribed. Higher doses of the medication have been shown to produce greater reductions in cholesterol levels.

It is important to note that the effectiveness of Lipitor and any medication can vary depending on the individual's overall health, lifestyle, and adherence to the prescribed treatment plan. It is recommended that individuals consult with their healthcare provider to determine the appropriate dosage and timeline for their specific condition.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/books/NBK430779/
[3] https://en.wikipedia.org/wiki/Atorvastatin