Declaring Preservatives and Their Levels on Your CNF

Preservatives cause more back-and-forth on Canadian filings than almost any other ingredient category. Not because makers are doing anything wrong on purpose, but because preservative systems are usually blends, the Hotlist sets limits by specific INCI name, and a small rounding habit can quietly push a declared number past a limit that the actual formula never crossed.

Why preservatives get extra scrutiny

The Cosmetic Ingredient Hotlist exists to flag substances that are prohibited outright or restricted to a maximum concentration, and preservatives make up a large share of the restricted list. Parabens, formaldehyde-releasing agents, and several others have specific caps tied to their INCI name. Since your CNF declares ingredients by INCI name with a concentration or concentration range, the preservative line on your form is one of the first things a reviewer checks against the Hotlist.

Get the real concentration, not the blend's label percentage

If you buy a preservative as a ready-mixed system, the percentage on the supplier's label or datasheet usually refers to how much of the blend you're using in your formula, not the concentration of each active component in your finished product. You have to expand the blend.

Say your supplier blend is used at 0.8% of your total formula, and the supplier's documentation says the blend itself is 70% Phenoxyethanol and 30% Benzyl Alcohol. The real concentrations that belong on your CNF are:

• Phenoxyethanol: 0.8% x 70% = 0.56%
• Benzyl Alcohol: 0.8% x 30% = 0.24%

If you instead declared "Preservative Blend" at 0.8% without breaking it down, the CNF has no way to represent that, since it wants each ingredient by its actual INCI name and level, and a reviewer checking it against the Hotlist can't evaluate a proprietary blend name at all.

A quick reference table

This is illustrative, not exhaustive. Hotlist limits and status can change, so always confirm the current entry for your specific ingredient before filing.

Preservative (INCI)	Typical use level	What to check
Phenoxyethanol	0.5% to 1.0%	Hotlist restriction status and current limit
Potassium Sorbate	0.1% to 0.5%	Generally lower scrutiny, still confirm current status
Sodium Benzoate	0.1% to 0.5%	Often paired with pH considerations
Benzyl Alcohol	0.1% to 1.0%	Also functions as fragrance ingredient in some formulas, check for double-counting
Methylparaben / Propylparaben	Varies	Restricted; confirm current Hotlist limit before use

Ranges versus exact figures

Health Canada's system lets you declare a concentration range rather than one fixed number, which is genuinely useful if your production varies slightly batch to batch. But a range still has to sit entirely inside whatever limit applies. If a preservative's Hotlist cap is a hard ceiling, your declared range's upper bound needs to be below that ceiling, not straddling it. Padding a range upward "just in case" is a common way makers accidentally declare a formula that looks non-compliant even when the actual product isn't.

Rounding can bite you

Preservative levels are often small numbers, half a percent or less, and small numbers are exactly where rounding errors matter most in relative terms. Rounding 0.58% down to 0.5% is a much bigger relative change than rounding 5.8% down to 5%. If your batch sheet and your CNF disagree because of rounding, use the batch sheet's real number on the form rather than a tidier-looking approximation.

Amendments when your preservative system changes

If you switch preservative systems, adjust the level, or your supplier reformulates their blend without telling you (this happens more than you'd think, ask for updated documentation periodically), you're expected to file an amendment reflecting the change. Don't treat a preservative swap as a minor tweak that doesn't need paperwork. It's exactly the kind of change the CNF is meant to track.

Where this gets easier

Reconciling blend percentages against Hotlist limits by hand is doable for one product but gets tedious across a full product line, especially if you use the same preservative blend across a dozen SKUs at slightly different levels. Cosmetic Comply matches each ingredient to its INCI name and CAS number, expands supplier blends into real component percentages automatically, and screens the result against the Hotlist with a confidence score before a human reviewer signs off and the notification gets filed.