Niacin deficiency causes pellagra , which can affect the skin, digestive system, and brain. The classic pattern is the “3 Ds” : dermatitis, diarrhea, and dementia , and severe untreated cases can be fatal.

Common effects

  • Skin problems: a photosensitive rash, rough or darkened skin, especially on sun-exposed areas.
  • Digestive symptoms: poor appetite, mouth or throat irritation, nausea, vomiting, abdominal discomfort, and diarrhea.
  • Neurologic symptoms: confusion, memory problems, depression, psychosis, and dementia.

Why it matters

Niacin is vitamin B3, and when it’s too low, the body can’t support normal cell energy production well, so symptoms show up across multiple systems. If you suspect niacin deficiency, it’s worth getting medical advice promptly because treatment is effective when started early.

If you want, I can also give you the early warning signs , causes , or food sources of niacin.