Lipitor (atorvastatin) is a medication that is used to lower cholesterol levels in the body, and it works by blocking the enzyme that produces cholesterol in the liver [1]. On the other hand, glucosamine is a dietary supplement that is commonly used to treat joint pain and osteoarthritis [2].

There is no direct evidence to suggest that glucosamine can counteract the effectiveness of Lipitor. However, it is important to note that some dietary supplements, including glucosamine, may interact with Lipitor and potentially affect its effectiveness. According to the NHS, it is generally safe to take glucosamine with Lipitor, but it is recommended to consult a doctor or pharmacist before taking any supplements while on Lipitor [2].

ConsumerLab also notes that there is a potential interaction between glucosamine and Lipitor, and recommends that individuals taking Lipitor should consult with their doctor before taking glucosamine or any other dietary supplement [3].

In summary, there is no direct evidence to suggest that glucosamine can counteract the effectiveness of Lipitor. However, it is important to consult with a healthcare professional before taking any dietary supplements while on Lipitor to ensure that there are no potential interactions that could affect the effectiveness of the medication.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.nhs.uk/medicines/atorvastatin/taking-atorvastatin-with-other-medicines-and-herbal-supplements/
[3] https://www.consumerlab.com/answers/which-drugs-should-be-avoided-when-taking-statins/statin-supplement-interactions/