Common Name(s): Sorbitan sesquiisostearate,sorbitan 1.5-isostearate,span-type isostearate sesquiester

DESCRIPTION

What It Does: Helps oil and water form stable emulsions with a smooth, non-waxy feel.

Why It's Used: The branched isostearate chain prevents crystallization and provides a non-waxy skin feel; sesquiester degree gives hlb between sorbitan mono- and diester.

How It Works: Branched isostearate chain prevents wax crystallization common in stearate analogs; sesquiester (1.5 acid/sorbitan) gives hlb ~4–5; suitable for w/o emulsification.

Typically Found In: Rich creams,w/o emulsions,body butters,anhydrous bases

TECHNICAL DETAILS

Primary Category: Functional ingredient – emulsifier

Secondary Functions: Emollient,skin conditioning

Application Areas:

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: Isostearic acid synthetic; sorbitan from plant sorbitol. [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

Sensitivity Concerns: Generally well tolerated.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Good safety profile. ewg score: 1.

Works Well With: Polysorbates,fatty alcohols,high-hlb emulsifiers,emollients

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Sesquiesters of sorbitan with branched (isostearate) fatty acids provide non-crystallizing w/o emulsifiers; hlb between span 60 (hlb 4.7) and span 80 (hlb 4.3); branching prevents the waxy buildup of stearate analogs.

Last Verified: 2026-03-27

Primary Sources: Cosing database,inci dictionary