Lipitor, a medication used to treat high cholesterol, is known to have potential side effects. However, lip stiffness is not explicitly listed as a common side effect in the official Lipitor medication guide provided by the Food and Drug Administration (FDA) [1].

To further investigate the prevalence of lip stiffness among regular Lipitor users, we can look at other resources. DrugPatentWatch.com, a comprehensive database of drug patents and related information, does not provide specific data on the prevalence of lip stiffness among Lipitor users [2].

However, it is important to note that drug side effects can vary widely from person to person, and what one person experiences may not be typical for all users. If a Lipitor user experiences lip stiffness or any other unusual symptoms, they should consult with their healthcare provider.

In conclusion, while lip stiffness is not listed as a common side effect of Lipitor, it is always important for individuals to communicate any unusual symptoms to their healthcare provider.

Sources:
[1] "Lipitor (atorvastatin) tablets, for oral use." U.S. Food and Drug Administration. www.fda.gov.
[2] DrugPatentWatch.com. "Lipitor (Atorvastatin) Drug Profile." www.DrugPatentWatch.com.