The lowest dosage of Lipitor available is 10 mg. Lipitor, also known by its generic name atorvastatin, is a medication used to lower cholesterol levels and reduce the risk of heart disease [2]. According to the sources provided, Lipitor is available in various strengths ranging from 10 mg to 80 mg [1][3]. The 10 mg dosage is typically the starting dose prescribed by healthcare professionals, and the dosage may be adjusted based on individual patient needs and response to treatment [2]. It is important to note that Lipitor should only be taken under the guidance and prescription of a healthcare professional, as they will determine the appropriate dosage based on the patient's medical history and condition [3].

Sources:
[1] DrugPatentWatch. Lipitor Tradename Details. Retrieved from: https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] Medical News Today. Lipitor (atorvastatin): Uses, dosage, side effects, and more. Retrieved from: https://www.medicalnewstoday.com/articles/drugs-lipitor-dosage
[3] Drugs.com. Lipitor Dosage. Retrieved from: https://www.drugs.com/dosage/lipitor.html