Science
Mechanism of Action
PEG-400 acts as a humectant by attracting water molecules from the environment and the deeper layers of the skin, retaining them through hydrogen bonding to maintain optimal skin hydration and suppleness. Its low molecular weight and excellent solubility enable it to function as a solvent and carrier, significantly improving the solubility and stability of active compounds and facilitating their enhanced delivery into or through the skin. Furthermore, it contributes to formulation elegance by modifying viscosity and stabilizing emulsions, preventing ingredient separation.
Research
Clinical Evidence
High confidence1%
Key findings
- 01 Functions effectively as a humectant and moisturizer across a concentration range of 0.01% to 20%.
- 02 A 10% concentration significantly enhances trans-ungual (nail) delivery of antifungals, demonstrating a 6-fold increase in drug delivery and a 2-fold increase in drug loading in in vitro permeation studies.
- 03 Used at 20%-30% in topical treatments for ichthyosis (dry, scaly conditions) to improve moisture retention and reduce scaling, with minimal systemic absorption or irritation observed.
- 04 A 30% PEG vehicle for salicylic acid (SA-PEG) demonstrated 75% efficacy in treating comedogenic acne, reducing comedones and papules without reported adverse effects.
- 05 Commonly utilized as a moisturizer in skincare products within a 1%-10% range, and in skin cleansers at 1%-3%.
- 06 Effective as a carrier for active ingredients at concentrations between 1%-5%, and as a thickening agent in serums and gels at 3%-10% or higher.
Transparency
Dusting Analysis
The provided research data does not indicate PEG-400 is commonly associated with 'dusting' concerns in skincare formulations.
The Formula
Formulation
Stability
PEG-400 exhibits high stability and compatibility with numerous active pharmaceutical ingredients and excipients. Its low volatility and high boiling point ensure stability even at elevated temperatures. It has also been shown to reduce the degradation of certain compounds, such as oxytetracycline, at higher pH levels (e.g., pH 9).
Synergies
- Enhances the solubility, stability, and epidermal delivery of various active ingredients, improving overall formulation efficacy.
Conflicts
- Can reduce the activity of specific antibiotics, including penicillin and bacitracin.
- May weaken the effectiveness of hydroxybenzene ester preservatives.
- Immiscible with substances such as beeswax, castor oil, gelatin, gum arabic, mineral oil, olive oil, and paraffin wax.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has affirmed PEG ingredients as safe for use in cosmetic products. Initial concerns regarding use on severely compromised skin (e.g., burn patients) were addressed in a 2010 re-review, which concluded that significant penetration leading to potential kidney toxicity only occurs with severe second and third-degree burns, leading to the removal of this caveat. PEGs generally exhibit low oral and dermal toxicity. The FDA permits related Triethylene Glycol as an indirect food additive and considers it Generally Recognized As Safe (GRAS). Manufacturers are advised to employ good manufacturing practices to limit impurities like 1,4-dioxane, a byproduct of ethoxylation.
Your Skin
Skin Compatibility
Our Assessment
Verdict
PEG-400 is an essential and highly versatile ingredient, prized for its humectant capabilities, its effectiveness in enhancing active ingredient delivery, and its broad compatibility across all skin types.
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References
Sources