Database/Viscosity Controlling/Hydroxypropyl Starch
Mostly natural · ISO 16128

Is Hydroxypropyl Starch natural?

Mostly. Lightly modified starch: the backbone is natural and the small hydroxypropyl substitution is petrochemical.

INCI nameHydroxypropyl Starch
CAS9049-76-7
FunctionViscosity Controlling
FeedstockCorn, potato or tapioca starch etherified with propylene…

How we scored it

Starch anhydroglucose unit 162.1 Da (natural) with hydroxypropyl groups from petrochemical propylene oxide at a typical molar substitution of 0.2 (0.2 x 58.1 = 11.6 Da); 162.1/173.7 = 0.93. The PubChem record shows a highly substituted trisaccharide fragment that does not represent the commercial cosmetic grade.
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

Starch alkoxide opens propylene oxide (SN2), then protonation. Each curved arrow moves one electron pair, and the film ends on the score above.

Where it comes from

Corn, potato or tapioca starch etherified with propylene oxide.

In plain English

A modified plant starch used to thicken and stabilize lotions and creams. Cornstarch is chemically modified with a petrochemical propylene-oxide derivative to improve its texture.

CosIng definition: Hydroxypropyl Starch is a propylene glycol ether of starch

Natural alternatives with the same function

Agar 100% natural origin

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 Agarose 100% natural origin

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 Algin 100% natural origin

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 Alginic Acid 100% natural origin

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 Aluminum Behenate 100% natural origin

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 Aluminum Distearate 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. 2HYDROXYPROPYL STARCH. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  3. 3HYDROXYPROPYL STARCH. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=HYDROXYPROPYL%20STARCH