Nanomaterials in Your Formula and What the CNF Expects

Zinc oxide and titanium dioxide show up constantly in mineral sunscreens and tinted moisturizers, and a lot of the versions suppliers sell are nano-sized for a reason: smaller particles blend more sheer and reduce the white cast people complain about. But nano-scale versions of an ingredient aren't automatically interchangeable with their non-nano counterparts on a Cosmetic Notification Form, and treating them as identical is a common filing mistake.

Why particle size matters to a notification

The Cosmetic Notification Form asks for your formula's ingredients by INCI name and concentration. That's straightforward for most substances. But when an ingredient is present in nanomaterial form, its behavior, absorption profile, and risk considerations can differ meaningfully from the same chemical at conventional particle size. Health Canada's guidance and the Cosmetic Ingredient Hotlist reflect this by treating certain nano forms with their own restrictions or disclosure expectations, separate from the bulk substance.

If your supplier's certificate of analysis or technical data sheet mentions "nano," "nanoparticle," or gives a particle size in the nanometer range, that's your signal to slow down and check how that specific ingredient's nano form is currently treated on the Hotlist before you file.

Where nano ingredients most commonly show up

• UV filters: nano zinc oxide and nano titanium dioxide in mineral and hybrid sunscreens (remember sunscreen itself sits in a different regulatory lane depending on the market, but the underlying ingredient disclosure logic still applies to how you describe the substance)
• Pigments: some nano-scale iron oxides or other colorants used for sheer coverage
• Delivery systems: encapsulated actives or nano-emulsions designed to improve penetration or stability of an active ingredient

What to gather before you file

1. Supplier documentation confirming particle size, ideally a certificate of analysis or a technical data sheet that states whether the material is nano-scale
2. The correct INCI name for the nano form, which may be listed distinctly from the conventional form
3. Current Hotlist status for that specific nano ingredient, since restrictions and requirements can be different from the non-nano version of the same chemical
4. Concentration or concentration range, calculated the same way as any other ingredient, remembering that if the nanomaterial arrives in a supplier blend, you need to carry the percentage through the blend's use level to get its real concentration in your finished product

A practical example

Say you're formulating a facial sunscreen-adjacent moisturizer (not a drug claim, just a cosmetic with a mineral pigment for tint) using a nano zinc oxide dispersion at 5% use level in your finished cream, where the dispersion itself is 40% zinc oxide. The zinc oxide's actual concentration in your finished product is 2%, not 5%, and that's the number that needs to appear correctly against the right INCI entry, along with an accurate description of its nano status, when you notify.

Don't assume "we've always used this ingredient" is a pass

Formulas evolve. A brand might switch suppliers for a "better" or more cosmetically elegant version of an ingredient it's used for years, not realizing the new supplier's version is nano-scale where the old one wasn't. That switch can quietly change what your notification should say, even if the INCI name on the label looks unchanged. It's worth asking suppliers directly whether particle size has changed whenever you requalify a raw material, not just when you're formulating something new.

When to file an amendment

If you're already selling a product and switch to a nano version of an ingredient, or discover partway through that your existing supply was nano all along, this is exactly the kind of change that triggers an amendment to your CNF rather than a fresh notification. Health Canada expects the notification to reflect what's actually in the product on the market, and particle size is part of that picture for the ingredients where it's flagged as relevant.

Nano disclosure is a narrow slice of what goes into a CNF, but it's one of the areas where a maker's good intentions (using a gentler, more elegant version of an ingredient) can quietly create a filing gap if the supplier paperwork isn't checked closely. Cosmetic Comply's ingredient matching flags the INCI and CAS details from your supplier documentation and screens each ingredient against the Hotlist before a filing goes out, which is a useful second set of eyes when a formula includes anything supplier data marks as nano-scale.