What's in my eyeliner?

The corpus

Eyeliner carries no SPF claim, so unlike foundation it is not regulated as an OTC drug in the United States and files nothing with the FDA. Every ingredient list here instead comes from the manufacturer's own official product page — still a first-party declaration, legally required under the FPLA labeling law, just not a government filing. Retailer listings (Sephora, Ulta, Amazon) are not used as sources, same standard as the foundation corpus.

Selection: liquid or pencil/kohl eyeliner only, chosen to span the same price tiers and parent companies as the foundation corpus. The ingredient list had to be published on the brand's own site — e.l.f.'s own flagship liquid liner does not publish ingredients online at all ("refer to the packaging"), so a different e.l.f. product stands in; see data/manifest-eyeliner.json for the full account.

Slide between two brands

Pick any two and watch the formulas converge or diverge. Matching ingredients line up; the rest is where the products actually differ.

Two vehicles, one category

5 of these 8 are liquid liners (water-based); 3 are pencil or kohl liners (wax-based, no water at all). Foundation's corpus is one vehicle — liquid, lotion, cream or emulsion — so its formulas share a real spine. Eyeliner's does not: a wax pencil and a water-based liquid liner are built from different chemistry to do the same job on the same part of the face, so "eyeliner" turns out to be two categories wearing one name.

The common spine (or lack of one)

Thirty most common ingredients