Common Name(s): Isoceteth-15,isoceteth-15,peg-15 isocetyl ether,branched c16 ethoxylate
DESCRIPTION
What It Does: Helps blend oils into water-based products and dissolves oil-soluble ingredients. the branched structure gives a clean, non-greasy finish on skin.
Why It's Used: Isoceteth-15 is selected for high-hlb (~14–15) solubilization with a non-crystallizing branched isocetyl tail — the methyl branching suppresses cetyl alcohol crystallization at skin temperature, providing fluid, waxy-residue-free emulsifier performance that straight-chain ceteth-15 at equivalent eo number cannot deliver.
How It Works: 15-eo chain → high hydrophilicity (hlb ~14–15); branched isocetyl c16 tail → oil phase anchoring + non-crystallizing fluid character; combined → o/w emulsification and oil-phase solubilization.
Typically Found In: Emollient formulas,o/w emulsions,essential oil solubilizers
TECHNICAL DETAILS
Primary Category: Functional ingredient – emulsifier
Secondary Functions: Solubilizing,skin conditioning
Application Areas:
Facial Skincare
Body Care
Hair Care
Beard Care
Color Cosmetics (Makeup)
Dietary/Oral Supplements
Typical Concentration Range: 0.5%–5%
SOURCING & ETHICS
Vegan Status: Conditional - feedstock declaration required
Halal Status: Unverified - feedstock declaration required (plant, animal and petrochemical routes all exist)
Source Notes: Isocetyl alcohol from synthetic or plant-derived source; eo from petrochemical. [audit 2026-07-29 rev2: origin-dependent: the same inci exists in plant, animal and petrochemical versions and the name does not discriminate. determination requires shariah-panel sign-off.]
SKIN COMPATIBILITY
Irritancy Rating: 1/5 – very low
Comedogenicity Rating: 1/5 – low; formulation-dependent
Sensitivity Concerns: Generally well tolerated. non-irritating at typical use concentrations.
Safe for Sensitive Skin: Yes
SAFETY & COMPATIBILITY
Safety Profile: Good safety profile. ewg score: 1–2.
Works Well With: Emollients,humectants,fragrance and essential oil solubilization
Avoid Combining With: No significant incompatibilities
SCIENTIFIC NOTE
Isocetyl branching provides measurable cloud point depression versus ceteth-15 (straight chain) — branching reduces hydrophobic aggregation tendency of the ethoxylate tail, enabling clearer solubilization of oil actives at lower use concentration.
Last Verified: 2026-03-27
Primary Sources: Cosing database,isoceteth-15 peg emulsifier review