Natural Extract Allergens Like Prunus and Related Notes

Most makers who've done their homework on fragrance allergens think in terms of named molecules, linalool, limonene, eugenol, things you can picture as a single chemical structure with a CAS number attached. The expanded List 2 set, aligned with international lists and mandatory in Canada on August 1, 2026, complicates that mental model a little, because some of what shows up there isn't a single molecule at all. It's a botanical extract, treated and disclosed as its own entry.

Why an extract can be its own allergen entry

A named molecule like linalool is one specific compound, full stop. A botanical extract, something like a Prunus species extract or certain other plant-derived materials, is a mixture of naturally occurring compounds, some of which may themselves be sensitizers. When international allergen lists include an extract as its own named entry, they're treating the whole extract, as commercially supplied and used, as the thing worth disclosing, rather than trying to isolate and name every individual sensitizing molecule that happens to be inside it.

This trips people up because it breaks the pattern. You start looking for "which molecule in my formula matches the list" and miss that the list itself sometimes names the source material.

What this means for formulation review

If your List 2 review process only checks single-molecule constituents against your fragrance blend's composition data, you can miss an extract-level entry entirely, especially if that extract entered your formula as an ingredient in its own right (a plant extract added for its own properties) rather than as part of a fragrance blend.

Practical steps that catch this:

1. Review your full ingredient list against List 2, not just your fragrance or essential oil components. An extract-level allergen entry might be sitting in your formula labeled as a skin-conditioning or antioxidant ingredient, not filed mentally under "fragrance."
2. Check both the INCI name and, where available, the botanical source name. Extracts are often named by plant part and species in INCI (bark extract, leaf extract, seed extract), and matching against a list entry may require recognizing the species name specifically.
3. Don't assume "natural" or "extract" means automatically exempt. These entries exist precisely because natural extracts can carry sensitizing potential, sometimes at meaningful concentrations, the same as any synthetic fragrance molecule.
4. Ask suppliers for composition data on extracts you use, similar to asking for allergen composition on an essential oil. A supplier's technical documentation should indicate whether known sensitizing constituents are present and at what typical level.

The concentration math still applies

The same disclosure thresholds that apply to single-molecule allergens apply here too: above 0.001% (10 ppm) in leave-on products and above 0.01% (100 ppm) in rinse-off products. The complexity isn't in the threshold, it's in correctly identifying that an ingredient in your formula is actually a listed entry in the first place, and then figuring out what concentration of the relevant extract you're actually using in the finished product.

A comparison to keep the two categories straight

Type of List 2 entry	Example pattern	What you check
Single molecule	A named chemical compound	Composition data from your fragrance/essential oil supplier
Botanical extract	A named plant-source extract	Whether the extract itself appears on the list, by species/part

Building this into your review habit

The safest approach is to stop treating "fragrance allergen review" as something you only run against your scent components. Run it against your entire finished formula, every INCI-named ingredient, because an extract entry can enter through a skincare-functional ingredient just as easily as through a perfume oil. This is also where supplier blends deserve extra attention: if a botanical extract in your formula arrived bundled inside a supplier's proprietary complex, you need to know it's in there and at what real concentration, the same expansion math you'd apply to any blended raw material.

Cosmetic Comply's ingredient screening step is built to run every mapped ingredient, INCI by INCI, extract or molecule, against the current allergen lists and flag what actually crosses a declaration threshold for your product type, rather than leaving it to a manual scan that's easy to miss when the entry isn't a molecule you were already watching for.