Database/Emulsifying Surfactant/Polysorbate 81
Mostly natural · ISO 16128

Is Polysorbate 81 natural?

Mostly. The sorbitan and oleic-acid core is natural, and Polysorbate 81's lower ethoxylation (versus Polysorbate 80) leaves a higher natural fraction.

INCI namePolysorbate 81
CAS9005-65-6
FunctionEmulsifying Surfactant · Cleansing Surfactant
FeedstockPolysorbate 81 is sorbitan mono-oleate (from sorbitol and…

How we scored it

Sorbitan (natural) + oleate (oleochemical) core 428.6 Da / total (+~5 EO petrochemical, 220.3 Da, POE-5 assumed for the '81' series) 648.9 Da = 0.66.
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.

How it’s made

Acid-catalysed ring closure of sorbitol (intramolecular SN2). Sorbitan is the ring at the core of every sorbitan ester and polysorbate. Each curved arrow moves one electron pair, and the film ends on the scores for the whole family.

Where it comes from

Polysorbate 81 is sorbitan mono-oleate (from sorbitol and vegetable-derived oleic acid) reacted with a small amount of petrochemical ethylene oxide, fewer moles than the more common Polysorbate 80.

In plain English

An emulsifying and cleansing ingredient made from sorbitol and vegetable-derived oleic acid, reacted with a small amount of ethylene oxide. Helps blend oil and water in cosmetic formulas.

CosIng definition: Sorbitan, mono-9-octadecenoate, poly(oxy-1,2-ethanediyl) derivs., (Z)-

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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. 2POLYSORBATE 81. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  3. 3POLYSORBATE 81. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=POLYSORBATE%2081