Pellagra may also cause a bright red tongue, nausea or vomiting, and fatigue, among other symptoms. However, niacin deficiency is often caused by malnutrition and is rare. The flushed, red skin ...

Niacin has long been used as an effective lipid-altering therapy, particularly for raising HDL-C and lowering triglyceride levels. In addition, niacin modestly lowers LDL-C levels. LDL-C ...