Database/Emulsifying Surfactant/Isosteareth-50
Mostly petroleum · ISO 16128

Is Isosteareth-50 natural?

Mostly not. Isostearyl fatty-alcohol backbone is oleochemical but is diluted by 50 petrochemical ethylene-oxide units, leaving little natural mass.

INCI nameIsosteareth-50
CAS52292-17-8
FunctionEmulsifying Surfactant · Cleansing Surfactant
FeedstockMade by reacting oleochemical isostearyl alcohol (derived from…

How we scored it

Isostearyl alcohol C18H38O 270.5 Da (natural, oleochemical) + 50 EO x 44.05 = 2202.5 Da (petrochemical); 270.5/2473 = 0.11. Supplied formula/MW (C22H46O3, 358.6) matches ~2 EO, not 50; description/name trusted over that formula.
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

Made by reacting oleochemical isostearyl alcohol (derived from isostearic/oleic acid) with a long chain of petrochemical ethylene oxide. The supplied PubChem formula appears to describe a lower-EO homolog, not the -50 grade.

In plain English

A mild cleansing and emulsifying ingredient made by combining a plant/animal-fat-derived fatty alcohol with a long synthetic chain of ethylene oxide, helping oil and water blend in a formula.

CosIng definition: Poly(oxy-1,2-ethanediyl), .alpha.-isooctadecyl-.omega.-hydroxy-

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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. 2ISOSTEARETH-50. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  3. 3ISOSTEARETH-50. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=ISOSTEARETH-50