Summing One Allergen Across Two Fragrance Sources

Here's a mistake that looks completely reasonable until you think about it for another ten seconds: checking each fragrance ingredient against the allergen threshold separately, one at a time, and concluding you're fine because none of them individually crosses the line.

The problem is the allergen doesn't know which bottle it came from. If linalool shows up in your essential oil blend and also in your fragrance compound, your skin, and the regulator, only cares about the total linalool in the finished product.

Why This Happens So Easily

A lot of formulas carry more than one scent source. A body butter might have a fragrance oil for the main scent profile plus a small addition of an essential oil for a marketing story, "with real lavender" printed on the front. Or a formula might use two different essential oils, say lavender and bergamot, that both happen to contain linalool as a major or minor constituent. Each source, taken alone, might land under the disclosure threshold. Combined, they don't.

If you check each fragrance ingredient in isolation and stop there, you'll systematically undercount allergens that show up in more than one place, which is common, since a handful of allergens like linalool, limonene, and geraniol are extremely widespread across essential oils and fragrance compounds.

Walking Through the Math

Say your rinse-off body wash contains:

• A fragrance compound at 0.8 percent of the formula, disclosed by the supplier as containing 2 percent linalool
• A separate lavender essential oil addition at 0.5 percent, with a certificate of analysis showing roughly 35 percent linalool

The linalool from the fragrance compound: 0.8 percent times 2 percent equals 0.016 percent, or 160 ppm, in the finished product.

The linalool from the lavender oil: 0.5 percent times 35 percent equals 0.175 percent, or 1,750 ppm, in the finished product.

Add them together: roughly 0.191 percent, or 1,910 ppm total linalool.

The rinse-off disclosure threshold is 100 ppm. Either source alone would have cleared that threshold on its own in this example, but the point stands more broadly: if you'd had two smaller sources that individually sat under 100 ppm but summed to something over it, checking them separately would have produced a false pass.

A Simple Table to Make the Point Concrete

Source	Use level in formula	Allergen concentration in source	Contribution to finished product
Fragrance compound	0.8%	2% linalool	0.016% (160 ppm)
Lavender essential oil	0.5%	35% linalool	0.175% (1,750 ppm)
Total linalool			0.191% (1,910 ppm)

Rinse-off disclosure trigger: 100 ppm. Total clears it by a wide margin, and would clear it even if either individual source were much smaller.

Building a Process That Catches This

The fix isn't complicated, but it does require discipline: build an allergen tally per finished product, not per raw material. For every fragrance-contributing ingredient in a formula, from a straightforward fragrance oil to an essential oil blend to a botanical extract that happens to carry natural allergen content, pull the allergen breakdown and calculate its finished-product contribution. Then group by allergen name, not by source ingredient, and sum before comparing to the threshold.

A few practical habits that help:

• Keep a running spreadsheet per SKU with one row per fragrance-contributing ingredient and one column per allergen, so the sums are visible rather than buried across separate supplier documents.
• Update the tally any time you reformulate, even a small tweak, since adding a second scent note to an existing product is exactly the kind of change that creates this multi-source overlap.
• Don't assume a "fragrance-free" marketing claim gets you out of this. Unscented or fragrance-free products can still carry allergens from other functional ingredients that happen to be on the list.

Where This Fits Into the Bigger Filing Picture

This kind of cross-ingredient summation is genuinely tedious to do by hand across a full product catalog, and it's exactly the kind of thing that's easy to get subtly wrong when you're managing dozens of SKUs with overlapping fragrance components.

Cosmetic Comply tracks allergen contributions at the ingredient level and totals them per finished product automatically, so overlapping sources get summed correctly before the screen runs, rather than relying on someone remembering to check twice.