Millions of patients take vitamin C supplements believing they support wellness, but new evidence reveals a significant concern: high-dose supplementation can dangerously interact with essential medications. Vitamin C supplements exceeding 2,000 mg daily have been shown to reduce the effectiveness of blood thinners like warfarin and apixaban, statins prescribed for heart disease, and certain chemotherapy agents used in cancer treatment. The mechanism is clear: vitamin C acts as a reducing agent that accelerates metabolism of vital clotting factors and interferes with drug absorption in the bloodstream. For patients managing chronic cardiovascular disease, cancer, or clotting disorders, these interactions pose serious health risks. The good news is that timing and transparency can mitigate risk. Healthcare providers recommend spacing vitamin C supplements at least 2 hours apart from medications and maintaining open communication with pharmacists and physicians about all supplement use before starting new treatments. Read the full article on GMJ Newsroom.
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