Database/Emulsifying Surfactant/Polysorbate 21
Mostly natural · ISO 16128

Is Polysorbate 21 natural?

Mostly. The sorbitan and lauric-acid core is natural, and Polysorbate 21's lower ethoxylation (versus Polysorbate 20) leaves a higher natural fraction.

INCI namePolysorbate 21
CAS9005-64-5
FunctionEmulsifying Surfactant · Cleansing Surfactant
FeedstockPolysorbate 21 is sorbitan monolaurate (from sorbitol and…

How we scored it

Sorbitan (natural) + laurate (oleochemical) core 346.5 Da / total (+~4 EO petrochemical, 176.2 Da, POE-4 assumed for the '21' series) 522.7 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 21 is sorbitan monolaurate (from sorbitol and coconut-derived lauric acid) reacted with a small amount of petrochemical ethylene oxide, fewer moles than the more common Polysorbate 20.

In plain English

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

CosIng definition: Sorbitan, monododecanoate, poly(oxy-1,2-ethanediyl) derivs.

Natural alternatives with the same function

Arachidic Acid 100% natural origin

A waxy fatty acid from peanut and other vegetable oils, used to thicken formulas and give creams and…

 Arachidyl Glucoside 100% natural origin

A gentle, sugar-based emulsifier used in creams and lotions to stabilize formulas without harsh surfactants. It's made from…

 Behenic Acid 100% natural origin

A long-chain fatty acid from vegetable oil, used to thicken and stabilise creams and conditioners. It is extracted…

 C10-16 Alkyl Glucoside 100% natural origin

A mild, sugar-based cleansing and emulsifying surfactant made by combining plant-derived fatty alcohols (coconut/palm) with glucose from starch.…

 C12-20 Alkyl Glucoside 100% natural origin

A mild, sugar-based cleansing ingredient made from coconut or palm fatty alcohols and glucose; helps cleanse skin and…

 C18-36 Acid 100% natural origin

A blend of long-chain plant fatty acids used as a mild cleanser and thickener, giving body and a…

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 21. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  3. 3POLYSORBATE 21. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=POLYSORBATE%2021