Hydrolyzed Wheat Protein
Also known as Hydrolysed Wheat Protein, HWP, Wheat Protein Hydrolysate, Hydrolyzed Wheat Gluten, HWG, Pronalen, Cropeptide, Gluadin, Glupal, Glupearl 19S, Tritisol
“CIR Expert Panel says: restricted.”
Hydrolyzed Wheat Protein (HWP; CAS 70084-87-6 plus 100209-50-5, 222400-28-4, 94350-06-8) is a heterogeneous mixture of peptides and free amino acids produced by acid, alkaline, or enzymatic partial hydrolysis of wheat protein (gluten). It is one of the most widely-used cosmetic conditioning agents (1,077 reported FDA VCRP uses; ~half in non-coloring hair products). Its safety profile is dominated by a documented dermal-sensitization mechanism: high-molecular-weight HWP applied via cosmetics can sensitize consumers to wheat protein epitopes, leading to immediate hypersensitivity reactions on subsequent oral wheat exposure (HWP-WDEIA, a clinical entity distinct from conventional WDEIA). The Japan facial-soap epidemic of the late 2000s, attributable to a 40,000-50,000 Da HWP preparation marketed as 'Glupearl 19S' in the brand 'Cha no Shizuku' soap, prompted independent regulatory action: the CIR Final Report (June 2014; PMID 29761728) and the SCCS opinion SCCS/1534/14 (June 2014, revised October 2014) both concluded HWP is safe ONLY when formulated to restrict peptides to a weight-average MW of <=3500 Da. The 3500 Da threshold derives from the immunological observation that a polypeptide must be at least 30 amino acids long (~3570 Da at 119 Da/amino acid) to carry the two IgE-binding epitopes required to crosslink mast-cell receptors. CIR and SCCS converged independently on this exact threshold from overlapping case-series evidence (Chinuki 2011, 2013; Fukutomi 2011; Hashimoto-Hill, Adachi 2012). This packet is the first hydrolyzed-protein entry in TheDose corpus and may serve as the class exemplar for hydrolyzed_protein patterns going forward.
Established functional uses: hair conditioning agent, skin conditioning agent, film former. Demonstrated substantivity to keratin substrates at low MW.
Low-MW HWP (<=3500 Da weight-average) carries no documented sensitization potential in the available CIR/SCCS evidence base, making properly-formulated HWP safe for use in cosmetics per both regulatory bodies.
Non-irritating in HRIPT studies at typical use concentrations: a 25% aqueous solution of MW=350 Da HWP showed no dermal irritation or sensitization in 52 subjects under occlusive patch (CIR FR 2014, p. 4).
MAJOR sensitization risk for high-molecular-weight HWP: multiple documented case series of contact urticaria followed by wheat-dependent exercise-induced anaphylaxis (HWP-WDEIA) on subsequent wheat-food ingestion, attributable to dermal/permucosal sensitization via cosmetics. The Japan 'Cha no Shizuku' facial-soap epidemic (Glupearl 19S, MW 40,000-50,000 Da) is the canonical case (Fukutomi 2011 PMID 21094523; Chinuki 2011, 2013 PMID 23205470).
Heterogeneous mixture concern: HWP is not a single chemical entity; molecular weight distributions span 0.1-90 kDa depending on hydrolysis method and conditions. A label declaration of 'Hydrolyzed Wheat Protein' does NOT communicate the MW profile of the specific raw material used. Without supplier disclosure or formulator GMP discipline, consumers cannot distinguish a CIR/SCCS-compliant low-MW HWP from a non-compliant high-MW HWP using the label alone.
Surfactant-coupled sensitization: SCCS/1534/14 specifically flagged that sensitization risk is amplified when HWP is paired with strong surfactant systems (soaps, liquid soaps) that may impair skin barrier and facilitate antigen penetration. Cleansing-format products with HWP merit elevated caution beyond what the headline 3500 Da rule conveys.
Cross-reactivity for wheat-allergic individuals: even low-MW HWP carries residual concern in already-sensitized individuals. Patients with conventional WDEIA may react to HWP fractions below 30 kDa per Fukutomi 2010 in vitro IgE data.
Known wheat allergy in food regulation: FDA (21 CFR §117) and EU (Regulation 1169/2011) require allergen labeling for wheat in foods; cosmetic regulations historically did not — a gap the SCCS opinion was responding to.
CIR Quick Reference Table (September 2022) — Hydrolyzed Wheat Protein row: Finding=SQ; Conclusion=safe when peptides restricted to weight…
CIR Final Report — Safety Assessment of Hydrolyzed Wheat Protein and Hydrolyzed Wheat Gluten as Used in Cosmetics (Burnett et al., releas…
“The CIR Expert Panel concluded that hydrolyzed wheat gluten and hydrolyzed wheat protein are safe for use in cosmetics when formulated to restrict peptides to a weight-average MW of 3500 Da or less.”— wheatp062014final.pdf, p. 11, CONCLUSION section
SCCS/1534/14 — Opinion on the safety of hydrolysed wheat proteins in cosmetic products (Sensitisation only); adopted at 6th plenary 18 Ju…
“The SCCS considers the use of hydrolysed wheat proteins safe for consumers in cosmetic products, provided that the maximum molecular weight average of the peptides in hydrolysates is 3,5 kDa.”— sccs_o_160.pdf (SCCS/1534/14), p. 19, section 4 CONCLUSION