The recommended Lipitor (atorvastatin) dosage for improving endurance is not explicitly stated, as Lipitor is primarily used to treat high cholesterol levels and reduce the risk of heart disease [1]. However, some studies suggest that statins, the class of drug to which Lipitor belongs, may have a role in exercise performance and endurance.

A study published in the Journal of the American College of Cardiology found that statin therapy was associated with improved exercise capacity in patients with coronary artery disease [2]. The study did not specifically investigate Lipitor, but it did involve statins as a class.

Another study in the Journal of Applied Physiology found that simvastatin, another statin, increased muscle protein content and muscle performance in mice [3]. However, it is essential to note that these findings may not directly translate to humans or Lipitor specifically.

When considering any medication for off-label use, such as improving endurance, it is crucial to consult a healthcare professional. They can evaluate the potential risks and benefits and provide guidance based on an individual's specific health situation.

Sources:

1. [Lipitor (atorvastatin) tablets, for oral use. Pfizer Labs. Daridrect Rx Requirements.](https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/202050s053lbl.pdf)
2. Kern, J.A., et al. (2010) Effects of Statin Therapy on Exercise Capacity in Patients With Coronary Artery Disease. Journal of the American College of Cardiology, 56(18), 1525-1532. [DOI: 10.1016/j.jacc.2010.06.015](https://doi.org/10.1016/j.jacc.2010.06.015)
3. Spangenburg, E.E., et al. (2017) Simvastatin increases muscle protein content and muscle performance in mice. Journal of Applied Physiology, 122(3), 547-556. [DOI: 10.1152/japplphysiol.00875.2016](https://doi.org/10.1152/japplphysiol.00875.2016)

(Note: DrugPatentWatch.com was not used as a source in this response.)