Science
Mechanism of Action
This ingredient functions as a reducing agent by targeting and breaking the disulfide bonds within the cysteine residues of hair proteins. This chemical modification disrupts the hair's natural structure, allowing it to be reshaped (e.g., permanent waves, straightening) or effectively removed (depilation). It concurrently contributes to maintaining optimal pH levels and overall product stability.
Research
Clinical Evidence
High confidenceApplication-dependent%
Key findings
- 01 The CIR Expert Panel found Ethanolamine Thioglycolate safe for hair straighteners, permanent waves, styling products, and hair dyes up to 15.2% (expressed as Thioglycolic Acid equivalent), emphasizing the need for hairdressers to minimize skin contact and consumer exposure.
- 02 Regulatory bodies including Health Canada and the EU permit its use in hair waving and straightening products at concentrations up to 8% for general use and up to 11% for professional use, within a pH range of 7 to 9.5.
- 03 For depilatory products, concentrations up to 5% are deemed safe when formulated to be non-irritating and used as intended (e.g., not daily or on large skin surfaces), typically with a pH between 7 and 12.7, as affirmed by CIR, SCCS, Health Canada, and EU regulations.
- 04 The SCCS also found it safe for professional eyelash applications up to 11%, though general consumer use on eyelashes is not advised due to potential eye irritation.
Transparency
Dusting Analysis
Ethanolamine Thioglycolate is primarily used in liquid or cream-based hair care and depilatory products, not typically as a powder requiring 'dusting' considerations in formulations.
The Formula
Formulation
Stability
Ethanolamine Thioglycolate exhibits stability at room temperature when stored in closed containers under standard conditions, but it is prone to oxidation upon air exposure. Studies indicate superior stability in gel preparations stored in glass bottles (97.8% active retention over 7 months) compared to polyolefin bottles (82.8% retention) under alternating temperature conditions. Optimal storage requires a cool, dry environment away from direct sunlight.
Conflicts
- Oxidizing agents, as they are incompatible with thioglycolates. Separation from such materials during storage is crucial.
- Long-term or extensive skin exposure, which may lead to allergic reactions.
Safety
Safety Profile
The CIR Expert Panel deems Ethanolamine Thioglycolate safe for specific hair applications up to 15.2% (as Thioglycolic Acid), provided that skin contact by hairdressers is avoided and consumer skin exposure is minimized. For depilatories, it is safe up to 5% when formulated to prevent irritation under recommended use, which typically excludes daily use or application on large skin areas. The SCCS cautions against general use on eyelashes due to significant eye irritation potential, reserving eyelash applications (up to 11%) for professionals only. It is listed in Annex III of the EC Cosmetics Regulation, signifying its permitted but restricted use.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Ethanolamine Thioglycolate is a powerful agent highly effective for its intended hair-altering applications, but its high irritancy and significant usage restrictions make it questionable for general precision skincare formulations.
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References
Sources