Niacin
Helps the nervous system, skin, and digestive system use energy from food.
Why it matters
Niacin helps the body turn food into energy and supports the nervous system, skin, and digestive system.
- Supports energy metabolism.
- Helps maintain skin and digestive health.
- Supports normal nervous system function.
If intake is too low
Severe niacin deficiency causes pellagra, classically linked with dermatitis, diarrhea, and mental changes. Untreated pellagra can become life-threatening.
- Rough or discolored skin changes.
- Digestive symptoms such as diarrhea.
- Mental changes, confusion, or dementia-like symptoms when deficiency is severe.
If intake is too high
High-dose niacin supplements can cause flushing, itching, and stomach upset, and very high doses can damage the liver.
- Flushing, itching, and burning sensations.
- Nausea or stomach upset.
- Liver injury, high blood sugar, and gout risk at very high intakes.
Adult upper limit: 35 mg/day
This upper limit is intended to reduce flushing and applies to niacin from supplements and fortified foods, not naturally occurring niacin in foods.
Common food sources
Niacin comes from protein-rich foods and fortified grain products.
- Poultry, beef, fish, and peanuts
- Brown rice and some mushrooms
- Fortified breads, cereals, and other grain products
Who may need closer attention
Severe deficiency is now uncommon, but risk rises when general nutrition is poor or absorption is disrupted.
- People with severe undernutrition or chronic alcohol misuse
- People with malabsorption disorders
- Anyone relying on high-dose niacin without understanding the difference between wellness dosing and medical dosing
Use extra caution if
Small details change the risk picture with nutrients more than most people expect.
You are using niacin for cholesterol management or already have liver disease, gout, or diabetes. High-dose niacin is a medical therapy, not a routine wellness dose.
Supplement and label notes
Useful context when this nutrient shows up across more than one product.
- Labels may use niacin or niacinamide; they behave differently in terms of flushing.
- High-dose niacin used for cholesterol is a medical therapy, not a casual add-on.
- If a supplement contains far more than the DV, double-check why it is there before assuming more is better.
Daily Value targets in SuppMap
These are the same label-style Daily Value targets used in the app.
Official references
These pages were used to draft the summaries on this guide.
Educational only. These pages are not a diagnosis or a substitute for personal medical care.
More guides
Keep moving through the rest of the Daily Value chart from here.