The ingredient, explained

Threonine

Threonine has published research relevant to cosmetic safety assessment.

AntistaticHair conditioningHair waving or straightening

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Ingredient guide

What it is and what it does

2-Amino-3-hydroxybutanoic acid

About this ingredient: EU CosIng ingredient registry (via Open Beauty Facts taxonomy) ↗

Antistatic: Reduces the build-up of static electrical charge on surfaces.
Hair conditioning: Improves cosmetic hair properties such as softness, shine or combability.
Hair waving or straightening: Changes hair structure to allow waving or straightening.

Function definitions: European Commission ingredient function definitions (SCCNFP/0299/00, pages 16 to 20) ↗

Registry functions describe possible formulation roles, not results for a finished product. A dictionary entry is not an approval or a safety assessment.

A closer look

What the research shows

Safety assessment

The report reviews irritation and sensitization evidence relevant to the named amino acids in topical cosmetics.

What this does not tell us

Grouped assessment includes read-across and combination formulations; this is safety evidence, not individual skin efficacy or an oral supplementation recommendation.

Sources for this summary. PubMed 24335967 ↗

Research review checked Oct 1, 2026

Selective exact-identity review of 1 supplied local candidates and the targeted primary-source search recorded below. Bounded review, not a systematic search.

Ingredient research is not proof that a product containing this ingredient works.