Science
Mechanism of Action
This ingredient functions primarily as an effective solvent, dissolving both water- and oil-insoluble components and increasing skin permeability to facilitate deeper penetration of active ingredients. It possesses antimicrobial properties that inhibit microbial growth, thereby extending product shelf life. As an astringent, it can help constrict tissues, minimize the appearance of pores, and reduce excess oil, contributing to a tightening sensation. Its rapid evaporation rate delivers a quick-drying, non-greasy, and matte finish, improving product aesthetics and texture. Additionally, it acts as an antifoaming and viscosity-decreasing agent.
Research
Clinical Evidence
High confidence12%
Key findings
- 01 SD Alcohol 40-B (a common denatured alcohol type) at 12% concentration was found to be non-irritating in a vaginal mucosal irritation test in rabbits.
- 02 A gel formula containing 29% SD Alcohol 40-B, and a spray liquid with 12% SD Alcohol 40-B, did not induce photoallergy, dermal sensitization, or phototoxic responses in human subjects.
- 03 Even at 55.65%, SD Alcohol 40-B denatured with Denatonium Benzoate produced minimal irritation in rabbits.
- 04 Incorporating emollients into propanol-based sanitizers demonstrated a reduction in skin dryness and irritation, suggesting potential mitigation strategies in formulations.
Transparency
Dusting Analysis
No data available in the provided research regarding dusting for this ingredient.
The Formula
Formulation
Stability
The ingredient itself has a neutral to slightly alkaline pH (7.0 - 7.2). It is incompatible with strong oxidizing agents, peroxides, various acids (including acid chlorides and acid anhydrides), alkali metals, and ammonia. As a reducing alcohol, it should not be mixed with potent oxidizers such as potassium dichromate, chromic acid, or osmium.
Synergies
- When formulated with emollients, alcohol's potential to cause skin dryness and irritation can be significantly reduced.
Conflicts
- strong oxidizing agents
- peroxides
- acids
- acid chlorides
- acid anhydrides
- alkali metals
- ammonia
- potassium dichromate
- chromic acid
- osmium
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel deemed Alcohol Denat. (including SD Alcohol 3-A, SD Alcohol 30, SD Alcohol 39-B, SD Alcohol 39-C, SD Alcohol 40-B, and SD Alcohol 40-C) safe for cosmetic use at concentrations between 0.05% and 12%, specifically when denatured with t-Butyl Alcohol, Denatonium Benzoate, Diethyl Phthalate, or Methyl Alcohol. However, CIR found insufficient data for alcohol denatured with Quassin, Brucine, and Brucine Sulfate. While the FDA classifies ethanol as generally recognized as safe for food, it has not approved it for long-term daily use as a consumer antiseptic wash. The CIR Expert Panel concluded that dermal application or inhalation of cosmetic products containing ethyl alcohol would not result in significant systemic exposure.
Your Skin
Skin Compatibility
Our Assessment
Verdict
While effective as a solvent and penetration enhancer and deemed safe by CIR up to 12% with specific denaturants, its high irritancy potential and 'avoid' rating from INCIDecoder necessitate careful consideration, particularly for dry or sensitive skin types. It may offer benefits for oily or normal skin in well-formulated products.
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