Database/Antioxidant/Acetyl Cysteine
Mostly natural · ISO 16128

Is Acetyl Cysteine natural?

Mostly. Cysteine backbone comes from fermentation while the N-acetyl group is added using petrochemical acetic anhydride.

INCI nameAcetyl Cysteine
CAS616-91-1
FormulaC5H9NO3S · 163.20 Da
FunctionAntioxidant · Skin Conditioning
FeedstockN-Acetylcysteine is made by acetylating fermentation-derived L-cysteine with…

How we scored it

Cysteine (fermentation amino acid) 121.16 Da natural + acetyl cap from acetic anhydride (petrochemical) 42.04 Da → 121.16/163.20 = 0.74.
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

N-Acetylcysteine is made by acetylating fermentation-derived L-cysteine with acetic anhydride. The amino acid dominates the mass; the acetyl cap is the only petrochemical fragment.

In plain English

An antioxidant and skin-conditioning ingredient derived from the amino acid cysteine, which is modified with an acetyl group. It is mostly plant/fermentation-derived, with a small petrochemical addition.

Natural alternatives with the same function

3-Glyceryl Ascorbate 100% natural origin

A stabilised, water-soluble form of vitamin C used as an antioxidant and humectant in skincare. It is made…

 Acacia Catechu Wood Extract 100% natural origin

An extract of the heartwood of the black catechu tree, rich in plant polyphenols such as catechin. It…

 Acer Palmatum Leaf Extract 100% natural origin

A plant extract from Japanese maple leaves, valued as an antioxidant. It's produced by simple extraction from the…

 Achillea Millefolium Flower Extract 100% natural origin

An extract made from yarrow flowers, a plant long used in traditional herbal preparations. Used to help condition…

 Adenosine 100% natural origin

Adenosine is a naturally occurring compound found in all living cells, playing a vital role in energy transfer…

 Aesculus Hippocastanum Extract 100% natural origin

An extract from the horse chestnut tree, used to soothe and protect skin and tighten its surface feel.…

Structure

2D structure of Acetyl Cysteine

(2R)-2-acetamido-3-sulfanylpropanoic acid

PubChem CID 12035 ↗

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. 2Acetyl Cysteine. PubChem CID 12035. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov ↗
  3. 3ACETYL CYSTEINE. CosIng — European Commission cosmetic ingredient database. ec.europa.eu/cosing ↗
  4. 4ACETYL CYSTEINE. CosIng u2014 European Commission database for information on cosmetic substances and ingredients. https://ec.europa.eu/growth/tools-databases/cosing/search?search=ACETYL%20CYSTEINE