Essential amino acid. Part of NMF, supports hydration and barrier.
Topical application
BLimited evidence. One RCT or several controlled studies with limitations.
Safe NMF amino acid.
Threonine (L-Threonine) is an essential amino acid. In skin – a component of proteins and part of the natural moisturizing factor (NMF). Mechanism. In the stratum corneum, NMF amino acids (including threonine, serine, alanine) retain water and support elasticity. Topically, in amino-acid complexes, threonine integrates into upper layers and acts as a mild humectant. Where applied. Serums and creams with amino-acid complexes, k-beauty products, repair masks. Final-product concentration rarely above 0.5%. Evidence base. Standalone topical-threonine RCTs are scarce. Most data are on NMF amino-acid complexes combined with hyaluronic acid and ceramides – synergistic hydration effect (Choi 2014). Safety. CIR confirmed safety. Hypoallergenic, non-comedogenic. No systemic absorption. Pregnancy and lactation – safe.
Irritation potential
LowAllergen risk
LowPregnancy
SafeSuitable for
The Evigrade extension adds an evidence panel to Wildberries, Goldapple, Letu, iHerb, Sephora and 12 more stores. This ingredient and every other one in the product show evidence-tier, allergen risk and pregnancy/lactation flags at a glance.
Threonine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
Threonine suits: normal, dry, oily, combination, sensitive.
Essential amino acid.
The INCI name is Threonine. It may also appear as: L-Threonine.
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