Niacinamide is a water-soluble vitamin that is used in skin treatments mainly orally, but also intravenously, and is generally not used as a topical medication. Since the drug cannot be absorbed through the skin, niacinamide has no effect when applied to the scalp. Niacinamide injection is mainly used for the prevention and treatment of pellagra with niacin deficiency, and it can also be used for the adjuvant treatment of coronary heart disease, viral myocarditis, and arrhythmia caused by digitalis intoxication, and it has the effect of preventing and treating heart conduction block. At the same time, it has the effect of preventing photosensitization. The adverse reactions of the drug are mainly manifested as skin flushing and itching, and occasionally side effects such as hyperglycemia and hyperuricemia can also occur. Nicotinamide injection is mainly used for the prevention and treatment of pellagra of niacin deficiency, at the same time, it can be used for the adjuvant treatment of coronary heart disease, viral myocarditis, and arrhythmia caused by digitalis intoxication, and it has the effect of preventing and treating cardiac conduction block. Adverse effects of the drug are mainly manifested as skin flushing and itching, and occasionally side effects such as hyperglycemia and hyperuricemia can also occur. Niacinamide tablets, as an oral preparation, are mainly used to prevent pellagra caused by niacin deficiency. Adverse effects of the drug mainly include nausea, epigastric discomfort, loss of appetite and dizziness, etc., which usually disappear on their own after stopping the drug. As its efficacy is greatly affected by individual factors, and needs to be used for a long time, please use the drug under the guidance of a doctor.