Antiperspirant residue
Two different marks from one product. The white transfer is the product itself. The yellow one is a slow accumulation that has been oxidising in the fabric for months.
In detail
Deodorant marks are two problems, and telling them apart decides whether anything can be done. The WHITE mark is straightforward: it is the product, transferred onto the fabric as it went over the head, sitting on the surface and generally coming off with mechanical action or washing. The YELLOW underarm mark is not that, and it is not a sweat stain either. Aluminium salts, the active in an antiperspirant, interact with the urea, amino acids, proteins, fatty acids and sebum in perspiration, and the products of that interaction deposit in the fabric as insoluble aluminium salts or soaps. The colour then develops SLOWLY, attributed at least in part to the oxidation of unsaturated fatty acids held in those insoluble salts. That is why the mark appears only after an extended period of repeated wearing and laundering, and why a shirt can look fine for a year and then not. Three consequences follow, and the third is the useful one. The stain depends on three things together — the formulation, the wearer's perspiration, and the washing agent used — so it is not purely a laundry failure. Ordinary detergent gives only partial removal and the marks persist through normal washing.
Why
- Antiperspirant residue is explained by Insoluble metal soaps
Sources for this page
Sources
Textile friendly non-aerosol antiperspirants with methanesulfonic acid, US patent US9549883B2
Henkel AG & Co. KGaA, granted by the United States Patent and Trademark Office, 2017 · Manufacturer documentation
Relied on for: That aluminium salts interact with urea, amino acids, proteins, fatty acids and sebum in perspiration to deposit insoluble aluminium salts or soaps, that the yellow colour develops with a time delay through oxidation of unsaturated fatty acids, that it appears only after repeated wear and laundering once a build-up has accumulated, and that normal washing removes it only partially. (states this directly)
Verification: a person has read the passage relied on.
Read on — The background section on textile discolouration by antiperspirant actives. Supports the claim as stated.
Last reviewed by a person on .