Lab marker · Low

Low Vitamin B3 (niacin): what it means

A Vitamin B3 (niacin) result below the normal range is considered low. Here is what a reduced Vitamin B3 (niacin) can point to, and when it is worth discussing with a doctor.

Reference range: assay-dependent; niacin is rarely measured directly — deficiency (pellagra) is usually a clinical diagnosis, and status can be assessed via urinary niacin metabolites

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What a low Vitamin B3 (niacin) can mean

  • Dietary deficiency — poor intake, especially maize-heavy diets low in other protein.
  • Alcohol dependence — a leading cause of pellagra today.
  • Malabsorption — gut conditions reducing uptake.
  • Rare metabolic disorders — Hartnup disease (reduced tryptophan uptake), carcinoid syndrome (tryptophan diverted).
  • Severe malnutrition or restricted diets.

When to discuss with a doctor

Niacin is rarely tested directly; a deficiency is usually recognised clinically from the pellagra picture — a symmetrical, sun-exposed rash, diarrhoea and changes in memory or mood — especially in someone with alcohol dependence, malabsorption or a very poor diet. Pellagra responds dramatically and quickly to niacin replacement, so recognising the pattern matters. Because B-vitamin deficiencies cluster, it is usually treated alongside a look at the wider B-vitamin and nutritional picture. Mediora.AI can surface a low niacin, or the associated skin, gut and neurological features, alongside the other B vitamins so the deficiency pattern is visible; confirming pellagra and starting treatment belongs with your doctor, and severe or rapidly progressing symptoms need prompt care.

Conditions this can relate to

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Mediora.AI is informational - interpretation, not a diagnosis. A single out-of-range value is common and often benign; always discuss decisions with your doctor.