Science
Mechanism of Action
Alcohol acts as an efficient solvent for various ingredients, dirt, and oils, contributing to better product consistency and homogeneity. It possesses antimicrobial and preservative qualities, inhibiting microbial growth and extending shelf-life. Functioning as an astringent, it can temporarily tighten pores and remove excess oil. Ethanol enhances the dermal absorption of other active ingredients by transiently disrupting the stratum corneum, possibly through lipid extraction or disorganization. Its volatility provides a quick-drying, weightless feel. However, at elevated concentrations, it can compromise epidermal barrier integrity, increase transepidermal water loss (TEWL), and thin the stratum corneum. Chronic exposure to high levels may lead to irritation, lipid depletion, free radical damage, inflammation, and exacerbate acne by stimulating sebaceous glands.
Research
Clinical Evidence
Medium confidence5%
Key findings
- 01 In a moisturizing cream, demonstrated no significant adverse effects on stratum corneum hydration, erythema, pH, or transepidermal water loss (TEWL) over 30 days on non-lesional atopic skin.
- 02 Reported to clear skin, unclog pores, and possess antibacterial and anti-inflammatory effects.
- 03 In ex vivo porcine skin studies, negatively impacted epidermal barrier integrity, increasing stratum corneum permeability and transepidermal water loss (TEWL).
- 04 Associated with potential skin irritation and dryness.
- 05 Presented no risk of skin drying due to complete evaporation during product application.
- 06 Caused no statistically significant changes in redness or capacitance with 20 or 100 daily applications for 14 days, compared to water.
- 07 Applied twice daily for 7 days, resulted in a decrease in skin hydration compared with water, though no changes in redness were observed.
Transparency
Dusting Analysis
Alcohol is frequently perceived negatively in skincare due to its potential for skin irritation and barrier disruption, particularly at concentrations exceeding 15%. While low percentages often evaporate rapidly and may be well-tolerated, higher amounts can compromise skin integrity, leading to dryness and inflammation, thus qualifying it as a 'red flag' ingredient for many consumers.
The Formula
Formulation
Stability
Formulations containing 20% or more alcohol are inherently preserved due to their high alcohol content.
Synergies
- Enhances the penetration of other active ingredients into the skin.
Conflicts
- High concentrations can disrupt the skin barrier and increase trans-epidermal water loss.
- May heighten the absorption of other ingredients, including potentially undesirable xenobiotics or irritants.
- Can induce dryness and irritation, especially detrimental for compromised or sensitive skin.
Safety
Safety Profile
The CIR Expert Panel considers Alcohol Denat. (including specific denaturants) safe for cosmetic use, citing low systemic exposure. However, topical ethanol can cause skin irritation or contact dermatitis, particularly in individuals with aldehyde dehydrogenase deficiency. Its permeation-enhancing abilities also carry a risk of increased absorption of other formulation components, including potential xenobiotics or carcinogenic contaminants.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Alcohol provides valuable formulation benefits as a solvent and penetration enhancer; however, its concentration-dependent effects on skin barrier integrity and a high risk of irritation necessitate careful formulation and consideration, especially for sensitive or compromised skin types.
Related
Similar Ingredients
Finding similar ingredients…