When a Blend Stays One Line and When It Must Split

Somewhere in your formula sheet there's probably a line that says something like "Preservative Blend X" at 1%, and no obvious way to know whether that counts as one ingredient or five. This trips up almost everyone the first time they fill out a Cosmetic Notification Form, because the answer depends on what the blend actually is, not on what the supplier calls it.

The short version

A blend stays as one line only when it has its own single INCI name recognized as such, water being the classic example (INCI: Aqua). Almost everything sold to you as a "blend," "complex," or "system" is not that. It is a mixture of two or more INCI-named substances that a supplier has premixed for convenience, and the CNF wants each of those substances listed separately, at its real percentage in your finished product.

The test is simple: does the thing have a single INCI entry that covers the whole mixture, or is it a proprietary combination of ingredients that each already have their own INCI names? If it's the second case, which is most trade-named blends, you split it.

Why the split matters

Health Canada's system screens ingredients against the Cosmetic Ingredient Hotlist by INCI name. If your filing says "Preservative Blend X 1%" and never mentions phenoxyethanol or ethylhexylglycerin by name, the restricted or prohibited substance check has nothing to match against. A blend that looks harmless as a trade name might contain something with a concentration cap you didn't know you were bumping into.

It also matters for the fragrance allergen disclosure rules coming into force in 2026. List 1 becomes mandatory on the CNF and label on April 12, and List 2 follows on August 1. Fragrance and essential oil blends are the most common place allergens hide, since compounds like linalool, limonene, and geraniol occur naturally in dozens of common oils. If your fragrance is filed as one opaque line, you cannot see whether any allergen crosses the 0.001% leave-on or 0.01% rinse-off disclosure threshold.

How to actually do the math

Get the blend's full composition from the supplier, usually in the SDS section 3 or a separate technical data sheet, then multiply each component's percentage in the blend by the blend's use level in your formula.

Example: your formula uses 1.0% of a preservative blend that is itself 80% phenoxyethanol and 20% ethylhexylglycerin.

Step	Calculation	Result
Phenoxyethanol in finished product	1.0% x 0.80	0.80%
Ethylhexylglycerin in finished product	1.0% x 0.20	0.20%

Those two numbers, not "1.0% Preservative Blend X," are what belongs on your CNF and, as a range or specific value, on your label.

When you genuinely can't get the breakdown

Some suppliers are cagey about exact ratios, especially for fragrance oils where the composition is proprietary. Ask anyway. A supplier who sells into the Canadian cosmetic market should be used to giving allergen breakdowns and full component lists for regulatory filing, and reputable ones will provide it under a mutual NDA if needed. If a supplier flatly refuses to disclose composition for a fragrance blend, that is worth treating as a red flag rather than a reason to file it as an opaque line.

A few things that legitimately stay whole

Some INCI names describe what looks like a mixture but is registered as a single entry, water again being the cleanest example since "Aqua" is the INCI itself, not shorthand for hydrogen and oxygen. Certain botanical extracts also have one INCI name covering a naturally complex plant material, even though chemically it's dozens of compounds. The dividing line isn't "is this chemically simple," it's "does INCI recognize one name for the whole thing." When in doubt, check the INCI dictionary entry directly rather than guessing from the trade name.

Building the habit

Every time a new blend shows up in a formula, before you touch the CNF, pull its component breakdown and do the multiplication first. Keep that math with your formula records so an amendment later, say a supplier changes their ratio, is a five-minute update instead of a re-derivation. Cosmetic Comply does this expansion automatically when you enter a formula, mapping each blend component to its INCI and CAS and carrying the real percentage through to the Hotlist screen, so you're not doing the arithmetic by hand every time a supplier tweaks a ratio.