A search for a polyhydroxystearic acid comedogenic rating usually opens a chart built for oils, butters, and fatty acids. Polyhydroxystearic Acid is not on that list as a triglyceride oil. It is a yellow liquid polymer of hydroxystearic acid, CAS 27924-99-8, used as a non-surfactant dispersant. A 0–5 number copied from a stearic row does not describe this lot.
The dispersant identity and the slurry step are Polyhydroxystearic Acid Dispersant for Mineral Filters. The fatty acid those charts often mean is Polyhydroxystearic Acid vs Stearic Acid in a Dispersion.
What the chart is scoring
Consumer comedogenic tables were assembled for materials that sit on skin as oils and waxes. Stearic acid is one of those materials: a free C18 fatty acid, solid at room temperature, CAS 57-11-4. Polyhydroxystearic acid is the polyester made from hydroxy stearic units. It is liquid on this product page. It is charged into an oil phase to wet powders. It is not the flake, and it is not soybean oil, isopropyl myristate, or any other row that happens to sit near “stearic” on a blog chart.
CIR’s 2023 assessment of this polymer does not publish a comedogenic score. It does publish a function, dispersing agent, and a conclusion of safe in the present practices of use and concentration in that report. It also records a neat-ingredient human repeat-insult patch test in 51 subjects that was not irritating or sensitizing. Irritation under a patch is not a pore-clogging grade. Do not convert “not irritating in that panel” into “comedogenic rating 0,” and do not convert the absence of a score into “comedogenic rating 5.”
If a brand spec says “non-comedogenic dispersant,” ask what test on the finished formula they mean. The raw-material COA for this liquid will show identity and whatever assay the factory reports. It will not show a 0–5 comedogenic integer unless that integer is actually on the document. Do not request a number the method does not produce.
Fungal-acne lists are the same kind of file
“Polyhydroxystearic acid fungal acne” is the same mismatch with a different list. Those lists flag fatty acids, esters, and some oils that the compiler treats as a risk for malassezia-prone skin. They are not a cosmetic specification, and they are not the CIR report. A row for stearic acid, or for a stearic ester, is not a row for this polymer.
This page will not clear the polymer for fungal-acne routines, and it will not condemn it. The purchasing act is to stop the substitution. If the brief forbids free stearic acid, that ban does not by itself ban Polyhydroxystearic Acid, and it does not by itself allow it. Write the INCI you will accept. If the brief forbids the polymer by name, do not ship Stearic Acid as a “simpler stearic.” That is a different INCI with its own chart problems.
What still has to be true on the order
A chart does not change the process. The liquid still belongs in the oil phase, mixed first with the pigments or mineral filters when that is the job, at the 1–5% start on this grade unless the TDS says otherwise. Titanium Dioxide remains a separate powder. Zinc oxide, if the formula needs it, is not sold on a page here. The dispersant does not become the UV filter because a consumer article discussed sunscreen texture.
“Side effects” and “is it safe for skin” belong with the CIR statement above, not with a comedogenic integer. The panel’s conclusion is about cosmetic use at the concentrations in that assessment. It is not a promise about every finished foundation, and it is not a medical claim. Patch results on the neat liquid do not predict how a high-solids sunscreen will feel.
Hydroxystearic acid, the monomer, is also outside the chart and outside this SKU. Do not let a list that says “hydroxystearic” collapse the monomer and the polymer into one bin.
What to send when the brief arrived as a chart
Put these lines in the message:
- INCI Polyhydroxystearic Acid, not Stearic Acid
- CAS 27924-99-8
- Form: yellow liquid dispersant, not a fatty-acid flake
- A statement that you are not asking the COA to invent a 0–5 comedogenic score
- Oil-phase use and the solids the slurry must wet
- Starting window 1–5%, or the level your TDS must confirm
- Bench-sample size, plus COA, SDS, and TDS
Documents and a sample are on the product page. Match the COA to the polymer, then run the finished-formula check your brand actually requires. A request that asks for “the non-comedogenic stearic” comes back as a question. A request that names the dispersant liquid comes back as a sample you can grind.
