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BUTYL ETHYL PROPANEDIOL.

Optional CAS 115-84-4 / HUMECTANT, SKIN CONDITIONING

A multifunctional aliphatic diol that serves as both a moisture-binding humectant and texture-enhancing emollient in skincare formulations. This synthetic ingredient excels as a solvent and penetration enhancer, helping improve the delivery and stability of other active ingredients while providing gentle hydration to the skin.

humectant solvent skin conditioning penetration enhancer emollient

Science

Works by attracting and binding moisture to the outermost layer of skin (stratum corneum) through its humectant properties, while simultaneously filling microscopic gaps between skin cells to create a smoother, softer surface texture. Additionally functions as a bioavailability enhancer, improving how other actives penetrate and perform in formulations.


Research

Medium confidence
Effective range 0.29–0.5%
Optimal

0.5%

Key findings

  1. 01 Demonstrated effective performance as solvent and stabilizer in anti-aging formulations, enhancing formula durability and texture
  2. 02 Showed non-sensitizing properties in guinea pig maximization testing at challenge concentrations up to 100%

Transparency

Not commonly dusted

Typically used at functional concentrations below 0.5% where it provides meaningful solvent and humectant benefits, making dusting unlikely in properly formulated products.


The Formula

Solubility
Both
Optimal pH 4 – 9
0 7 14

Stability

Exhibits superior hydrolytic resistance compared to neopentyl glycol and maintains stability across typical cosmetic pH ranges. Performance may be compromised in highly alkaline environments above pH 10.

Synergies

  • UV filters and sunscreen actives
  • Anti-aging peptides and vitamins
  • Other humectants like hyaluronic acid

Conflicts

  • Extremely high pH (>10) environments
  • Strong oxidizing agents

Safety

CIR Status
Safe as used
Max tested
0.29%
Sensitization risk Low

CIR Expert Panel concluded safety for current cosmetic use practices. Exhibits slightly higher irritation potential than 1,3-propanediol in concentrated forms, but remains generally well-tolerated.


Your Skin

Yes Normal
Yes Dry
Yes Oily
No Sensitive
Irritancy Low
Comedogenicity Low

Our Assessment

Optional

A competent multifunctional ingredient that enhances formula performance and provides mild hydration benefits, though not essential for most skincare routines.


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References