Nicotinamide vs Nicotinic acid: what is the difference?
Niacin is nicotinic acid, whose acid group causes the skin flush, while niacinamide is nicotinamide, the amide form of vitamin B3, which does not flush.
Nicotinamide has NH2 where nicotinic acid has OH: an amide in place of an acid.
Sources and notes
- The sentence under the titlefrom sourceMoleculeFinder comparison notesThe pair's answer line.
- The two drawingscomputedMoleculeFinder rule (RDKit MCS)Drawn the same way round on the skeleton they share; the amber marks where the two differ.
- The captionfrom sourceMoleculeFinder curated
- What is highlightedfrom sourceMoleculeFinder curatedOne line under each drawing, written from the atoms the amber marks.
- Structural similaritycomputedRDKit Morgan/Tanimoto0.65 of 1, a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.
Side by side
| Nicotinamide | Nicotinic acid | |
|---|---|---|
| Molecular weightCalculated PubChem | 122.12 g/molC6H6N2O | 123.11 g/molC6H5NO2 |
| Hydrogen-bond donorsCalculated PubChem | 1 | 1 |
| Where each turns upEditorial MoleculeFinder food and product lists |
|
|
| FamilyEditorial MoleculeFinder curated | Vitamins | Vitamins |
| Everyday groupEditorial MoleculeFinder curated | Nutrient | Nutrient |
| Chemical groupsCalculated Found by rule (RDKit) | Amides | Carboxylic Acids |
| Hazard labelReported ECHA, HSDB via PubChem | Warning | Warning |
| The supplier-filed hazard label's signal word, not a statement about ordinary use. | ||
| Oral LD50Measured HSDB via PubChem | 3,500 mg/kgpure nicotinamide, rat, oral | 7,000 mg/kgpure nicotinic acid, rat, oral |
| A single acute animal measure. It ranks nothing about human safety. | ||
Sources and notes
- Molecular weightcomputedPubChemComputed from the structure; the formula is under each weight.
- Hydrogen-bond donorscomputedPubChemThe hydrogens on nitrogen or oxygen that each molecule can lend to a hydrogen bond, counted from its structure.
- Where each turns upfrom sourceMoleculeFinder food and product listsEach amount is an editorial figure from our lists, not a measurement of any one product. Each mark is set by hand on the list, never inferred.
- Familyfrom sourceMoleculeFinder curated
- Everyday groupfrom sourceMoleculeFinder curated
- Chemical groupscomputedFound by rule (RDKit)Each group is found in the structure by a chemical pattern.
- Hazard labelfrom sourceECHA, HSDB via PubChem
- Oral LD50from sourceHSDB via PubChem
- ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
- Identifiersfrom sourcePubChemPubChem CID 936 (Nicotinamide) and 938 (Nicotinic acid).
In more detail
Both end up as the same coenzyme, NAD, but they behave very differently on the way there. Niacin is nicotinic acid, carrying a carboxylic acid group, and at high intakes it causes the flush, a temporary reddening and prickling of the skin driven by prostaglandin release. Nicotinamide carries an amide instead and does not cause the flush at all, which is why supplements sold as flush-free use it. That same carboxylic acid is why niacin, and not nicotinamide, has effects on blood lipids. In skincare the amide form is the one used, listed as niacinamide, where it is studied for barrier function and pigmentation.
Sources and notes
- The paragraphfrom sourceMoleculeFinder comparison notes
Questions
- What is the difference between Nicotinamide (Niacinamide) and Nicotinic acid (Niacin)?
- Niacin is nicotinic acid, whose acid group causes the skin flush, while niacinamide is nicotinamide, the amide form of vitamin B3, which does not flush.
- Is Nicotinamide bigger than Nicotinic acid?
- Nicotinic acid is the heavier molecule, 123.11 g/mol against 122.12 g/mol for Nicotinamide. Nicotinamide is C6H6N2O and Nicotinic acid is C6H5NO2.
- Which has the lower reported LD50, Nicotinamide or Nicotinic acid?
- Nicotinamide, at 3,500 mg/kg (oral, rat), against 7,000 mg/kg (oral, rat) for Nicotinic acid. An LD50 is one acute animal measurement, and the two here were not necessarily measured in the same species, so it is a data point rather than a ranking of how dangerous either is to a person.
Sources and notes
- The answersfrom sourceMoleculeFinderThe first is the pair's answer line; the others are read off the table above.