Database/Hair Conditioning/Sodium Polyaspartate
Route-dependent · ISO 16128

Is Sodium Polyaspartate natural?

It depends. The backbone is polymerised aspartic acid, which is natural when fermented from glucose and petrochemical when made enzymatically from maleic-anhydride-derived fumaric acid. Sodium is a mineral counter-ion and counts as natural origin on both routes, so the petrochemical route is 0.17 rather than zero.

INCI nameSodium Polyaspartate
CAS94525-01-6
FunctionHair Conditioning · Humectant
FeedstockAspartic acid is either fermented from glucose or…

Why the score varies

This ingredient is made commercially by more than one route, and ISO 16128 scores the feedstock actually used. Without a supplier certificate of origin the value cannot be claimed.

RouteFeedstockNOIShareNotes
Fermentation-derived L-aspartic acid, thermally polymerised and neutralisedglucose fermentation1.00minority
Enzymatic amination of petrochemical fumaric acid (aspartase + ammonia)maleic anhydride to fumaric acid, natural-gas ammonia0.17majorityonly the 22.99 Da sodium counter-ion is natural origin
Ask your supplier. A batch-specific certificate of origin or bio-based carbon test (ASTM D6866) settles which route applies.

How we scored it

The repeat unit is C4H4NO3Na, 137.07 Da, of which the sodium counter-ion is 22.99 Da. Fermentation-derived aspartic acid makes the whole unit natural origin, 137.07/137.07 = 1.00. Aspartic acid made from petrochemical fumaric acid and ammonia leaves only the mineral sodium as natural origin, 22.99/137.07 = 0.17.
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

Aspartic acid is either fermented from glucose or produced by enzymatic amination of petrochemical fumaric acid with ammonia. The acid is then thermally polymerised and neutralised with sodium hydroxide, whose sodium comes from mineral salt.

In plain English

A biodegradable polymer of the amino acid aspartic acid, used to condition hair and skin and help hold moisture.

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