The INCI designation “Hydrolyzed Wheat Protein” is among the most widespread conditioning actives in professional hair cosmetology. Yet behind this name lies a chemical reality that most labels do not clarify: the molecular weight of the peptides entirely determines their site of action on the fiber. Hairswiss decodes.
What is hydrolyzed wheat protein? Chemical definition
Hydrolyzed wheat proteins (Hydrolyzed Wheat Protein, INCI) are peptides obtained by acid, alkaline or enzymatic hydrolysis of gluten from Triticum vulgare. Gluten is a storage protein network composed mainly of gliadins (MW 28–55 kDa) and glutenins (MW 80–800 kDa). Hydrolysis fragments these macromolecules into peptides of MW 300–5,000 Da, depending on the intensity and type of hydrolysis.
The fractions obtained are rich in glutamine (Gln, ~35% of residues), proline (Pro, ~15%) and hydrophobic amino acids — a composition that favors adsorption onto keratin through hydrogen bonds (Gln–Gln) and hydrophobic interactions.
Molecular weight determines the site of action
Light fractions (<1,000 Da)
Peptides with MW below 1,000 Da (di-, tri-, tetrapeptides, ~3–8 amino acids) can partially penetrate the hair cortex via inter-cuticular spaces and diffusion channels of the lifted cuticle. They adsorb onto internal keratin chains and contribute to reducing intrafibrillar water loss, improving fiber hydration and plasticity. These fractions are particularly useful for highly porous hair.
Heavy fractions (1,000–5,000 Da)
Peptides with MW above 1,000 Da do not penetrate the cortex. They adsorb onto the cuticle surface through electrostatic and hydrogen bonds, forming a thin conditioning film. This film reduces the inter-fiber friction coefficient, fills cuticular gaps in damaged zones and improves shine through surface smoothing. Their substantivity is moderate — they resist rinsing but are removed by repeated shampooing.
Hydrolyzed wheat protein vs. hydrolyzed keratin
Both are hydrolyzed proteins, but their affinity for the fiber differs. Hydrolyzed keratin, derived from animal keratin, shares an amino acid composition closer to human hair keratin — notably a higher cysteine (Cys) content that allows sulfur-sulfur interactions with the cuticle’s disulfide bonds. Hydrolyzed wheat proteins are richer in glutamine and proline and act primarily through hydrogen bonds and non-covalent interactions. Their cationic modified fractions (Hydroxypropyltrimonium Hydrolyzed Wheat Protein) show enhanced electrostatic affinity for the anionic cuticle.
Professional products: Wheat Protein in formulation on cliCHair
Among the products available on cliCHair.ch integrating hydrolyzed wheat proteins as an identifiable conditioning active in their INCI list, several references stand out.
Curly Up Shampoo and Curly Up Mask — Edelstein
The Curly Up line integrates hydrolyzed wheat proteins in combination with grapeseed oil and glycerin. This combination specifically targets curly hair with high differential porosity: the peptides fill cuticular gaps responsible for irregular water absorption, while glycerin maintains hydration between washes. Professionals will find on cliCHair.ch the Curly Up Shampoo and the Curly Up Mask.
Eco Hairspray — Edelstein
Gas-free hairspray integrating wheat proteins in a hydro-alcoholic base. The peptides deposit on the cuticle during solvent evaporation, complementing the film-forming action of the resins with a light conditioning effect. The Eco Hairspray is available on cliCHair.ch.
What Hairswiss concludes
Hydrolyzed wheat proteins are not all equivalent: their molecular weight determines whether they act in the cortex (fractions <1,000 Da) or at the cuticle surface (fractions >1,000 Da). Cationic modified versions (Hydroxypropyltrimonium Hydrolyzed Wheat Protein) show better substantivity through electrostatic attraction. Without MW indications in the INCI list, the ingredient’s position in the list gives an approximate concentration indication — but no information on the fraction used.