N-acetyl glucosamine (NAG) is an amino sugar the body makes and uses constantly — it is one of the two building blocks of hyaluronic acid, and a repeating unit in the glycosaminoglycans that give the dermis its cushioning.
How it works
Supplying NAG topically feeds the machinery rather than the surface: research has associated it with increased hyaluronic acid production in skin, which reads as hydration and plumpness generated from within rather than filmed on top. Separately, NAG has been shown to slow the conversion steps in melanin production — with its best-known clinical result coming in combination with niacinamide, where the pair outperformed either alone against uneven tone.
It is also a gentle normaliser of surface-cell shedding, contributing a very mild smoothing effect without acid chemistry.
In formulation
Appears in hydrating serums, brighteners and eye products, usually between two and eight percent. Exceptionally well tolerated — non-acid, non-photosensitising, suitable in pregnancy — which makes it a favourite supporting player in formulas whose lead actives carry the intensity.
Worth knowing
NAG is commonly produced from shellfish shells, though fermentation-derived versions exist; those with severe shellfish allergy sometimes prefer to patch test, although reactions to the purified sugar are not the same as reactions to shellfish protein and are rarely reported.
