Taking niacin helps the body convert food into energy, which is an essential part of weight lifting. Consuming too much niacin is shown to cause rashes and flushed skin, explains Lisa Freedman for Men's Fitness.
Niacin is a B vitamin, which is found in many foods such as yeast, meat, fish, milk, eggs, beans and cereal. It can also be taken as a prescription or a dietary supplement. B vitamins, such as niacin, convert carbohydrates into glucose, which is burned to produce energy, according to Freedman. Niacin is also shown to help metabolize fat and protein and aid in nervous system function. It is often cited for its ability to lower LDL cholesterol while raising HDL cholesterol. HDL cholesterol moves bad cholesterol to the liver for removal, says WeightTraining.com.
Excessive use of niacin can cause redness of the skin and liver damage, claims Freedman. Many of these side effects dissipate over time, but if not, consult a doctor, recommends WeightTraining.com. Niacin may also cause a dangerous spike in the glucose levels of diabetics. Diabetics should consult a doctor before beginning a regimen of niacin. Those who have liver disease, kidney disease or stomach ulcers should avoid niacin supplements. Niacin should also be avoided by woman who are pregnant or nursing as the supplement may harm the baby.