Temporary flushing, itching, rash, or gastric disturbances may occur. Liver function testing is recommended when niacin is taken in excess of 500 mg daily. Those with gout or liver diseases should avoid taking high doses of niacin. Consult with your doctor before using this product if you are taking anticoagulant medications. Individuals consuming more than 2,000 IU/day of vitamin D (from diet and supplements) should periodically obtain a serum 25-hydroxy vitamin D measurement. Vitamin D supplementation is not recommended for individuals with high blood calcium levels. Individuals with in-born errors of copper metabolism (e.g. Wilson?s disease) should avoid daily, chronic use of this product.Do not purchase if outer seal is broken or damaged.When using nutriti.