Niacin overdose: What are the symptoms?

    I take niacin to treat my cholesterol. Should I be concerned about a niacin overdose?

    Niacin overdose is unlikely if it's taken as prescribed by your healthcare professional. You can't overdose on niacin by eating too many niacin-rich foods. But it is possible to overdose if you take too much over-the-counter or prescription niacin. Over-the-counter niacin doesn’t require a prescription.

    Symptoms of a niacin overdose include:

    • Severe skin flushing combined with dizziness.
    • Rapid heartbeat.
    • Itching.
    • Nausea and vomiting.
    • Abdominal pain.
    • Diarrhea or constipation.
    • Gout.
    • Rash.
    • Muscle weakness.

    If you think you may have overdosed, get medical help right away.

    Niacin has been linked to liver damage and strokes. For this reason, most healthcare professionals now recommend niacin only for people who can't take statins to reach their cholesterol goals or in other very specific circumstances.

    If you're concerned about taking niacin, talk to your healthcare professional.

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    3. Pazirandeh S, et al. Overview of water-soluble vitamins. https://www.uptodate.com/contents/search. Accessed March 1, 2026.
    4. Melmed S, et al. Disorders of lipoprotein metabolism. In: Williams Textbook of Endocrinology. 15th ed. Elsevier; 2025. https://www.clinicalkey.com. Accessed March 1, 2026.
    5. Niacin. Merative Micromedex. https://www.micromedexsolutions.com. March 1, 2026.
    6. Niacin toxicity. Merck Manual Professional Version. https://www.merckmanuals.com/professional/nutritional-disorders/vitamin-deficiency-dependency-and-toxicity/niacin-toxicity. Accessed March 1, 2026.
    7. Medical review (expert opinion). Mayo Clinic. May 26, 2026.

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