Database/Emulsifying Surfactant/PEG-9 Isostearate
Mostly petroleum · ISO 16128

Is PEG-9 Isostearate natural?

Mostly not. Polyethylene glycol ester of isostearic acid. The fatty-acid chain is natural; the 9-unit ethylene-oxide chain is petrochemical.

INCI namePEG-9 Isostearate
CAS56002-14-3
FunctionEmulsifying Surfactant
FeedstockIsostearic acid from oleic-acid dimerisation (oleochemical) esterified or…

How we scored it

PEG-9 Isostearate: isostearoyl fragment C18H35O 267.5 Da (natural) of isostearic acid 284.5 Da + 9 EO 396.5 Da = 681.0 Da → 0.39. The ester oxygen and chain-end hydrogen go with the PEG chain, as for PEG-8 Laurate.
What counts. ISO 16128-2 scores the atoms that remain in the final ingredient. Reagents, solvents, catalysts and protecting groups used during manufacture leave no mass behind and are not counted.

Where it comes from

Isostearic acid from oleic-acid dimerisation (oleochemical) esterified or ethoxylated with about 9 mol of ethylene oxide.

In plain English

An emulsifier made from a branched vegetable-oil fatty acid and a short synthetic ethylene oxide chain, used to blend oil and water in cosmetics. A little over a third natural by weight.

CosIng definition: Poly(oxy-1,2-ethanediyl), .alpha.-(1-oxoisooctadecyl)-.omega.-hydroxy- (9 mol EO average molar ratio)

Natural alternatives with the same function

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 C10-16 Alkyl Glucoside 100% natural origin

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 C12-20 Alkyl Glucoside 100% natural origin

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 C18-36 Acid 100% natural origin

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References

  1. 1ISO 16128-1:2016 and ISO 16128-2:2017 — Guidelines on technical definitions and criteria for natural and organic cosmetic ingredients and products. ISO, Geneva.
  2. 2PEG-9 ISOSTEARATE. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  3. 3PEG-9 ISOSTEARATE. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=PEG-9%20ISOSTEARATE