Sheet Mask Essence: Listing the Soaked Formula on a CNF

Sheet masks confuse first-time filers in a specific way: there are two physical components in the package, a fabric or hydrogel sheet and a liquid essence it's soaked in, and only one of them is actually what you're notifying. If you've been staring at your product wondering whether the sheet material itself needs an ingredient declaration, the short answer is no, and here's why that matters for how you build your filing.

The sheet is packaging function, the essence is the product

The fabric, whether it's cotton, bio-cellulose, hydrogel, or a biodegradable fiber blend, exists to hold and deliver the essence to the skin. It's functioning more like a delivery mechanism than an active cosmetic ingredient in its own right. What actually contacts the skin with intentional cosmetic function, and what carries your actives, humectants, and preservative system, is the essence liquid. That's the formula Health Canada needs the INCI breakdown for on your Cosmetic Notification Form.

This doesn't mean the sheet material is irrelevant to your business. You still want to know what it's made of for supply chain and marketing reasons, and if it's treated with anything (some biocellulose sheets are processed with substances during manufacture), that's worth a conversation with your supplier. But the notifiable ingredient list, the one requiring INCI names and concentrations, is the essence.

Getting the essence concentration right

The tricky part with sheet masks specifically is that the essence isn't sold as a bottled serum with a clean, fixed volume, it's absorbed into the sheet and the sheet is sold as the whole unit. You still need to declare the essence's own internal formula percentages, meaning what percentage of the essence liquid itself is water, what percentage is glycerin, what percentage is your active, and so on, exactly as you would for a serum sold in a dropper bottle.

A common mistake is trying to calculate ingredient concentration relative to the total package weight, factoring in the sheet's absorbed weight into the math. Don't do that. The essence formula is declared as its own self-contained percentage breakdown, the same way any liquid cosmetic would be, independent of how much of it a given sheet happens to absorb or how the consumer experiences dosing.

Where supplier blends complicate this further

Sheet mask essences are often built around one or two hero actives layered onto a base humectant system, and both the actives and the base frequently arrive from suppliers as proprietary blends. If your essence contains a "hyaluronic acid complex" blend at 3% use level, and that blend itself is, say, 5% sodium hyaluronate with the rest carrier, the real concentration of sodium hyaluronate in your finished essence is 0.05 times 0.03, or 0.15%. That's the number that belongs on your CNF, not the blend's trade name or its own internal percentage in isolation.

A simplified example essence breakdown

Component	Role	Example concentration in essence
Aqua	Solvent base	Balance to 100%
Glycerin	Humectant	5%
Sodium Hyaluronate	Humectant, active	0.15% (from a 3% blend at 5% internal concentration)
Panthenol	Skin conditioning	1%
Phenoxyethanol	Preservative	0.6%
Fragrance components	If above allergen thresholds	Declared individually

Preservative systems deserve extra attention here

Sheet masks sit in a sealed, moist environment for weeks or months before use, which makes preservative adequacy a real formulation concern, separate from the notification itself. While preservation efficacy testing isn't the CNF's job to verify, it's worth making sure your preservative system is genuinely appropriate for a high-water, sealed-pouch product before you're filing ingredient percentages for something that isn't actually stable on the shelf.

Filing it cleanly

When you sit down to file, treat the essence exactly like you'd treat a serum: full INCI list, real concentrations or ranges, blends expanded into their actual components, checked against the Cosmetic Ingredient Hotlist. The sheet material itself typically doesn't need its own INCI declaration on the CNF, but keep your supplier documentation on it in your own files in case a customer or retailer asks. If you're filing several sheet mask essence variants that share a common base with different actives, Cosmetic Comply's duplicate-filing feature lets you reuse the shared base formula and swap in the differing active percentages, rather than rebuilding the whole notification from scratch for each variant.