When a Supplier Refuses to Share Ingredient Percentages

You email the supplier asking for the exact percentage of each component in their "hair repair complex," and you get back a one-line reply: "that's proprietary." Now what. This happens constantly with specialty blends, and there are a few real paths through it, none of which involve just guessing.

Why suppliers hold this information back

A blend's exact ratio is often the actual intellectual property being sold. If a supplier tells every customer the precise percentage of each active in their signature complex, a competitor could reverse-engineer and undercut them. So the reluctance isn't usually bad faith, it's a legitimate business protection. That said, you still need real numbers to notify your product correctly, because a notification requires ingredients listed by INCI name with a concentration or concentration range, and "proprietary blend" isn't a percentage.

Start with the safety data sheet

Every supplier is expected to provide a safety data sheet, and section 3 of an SDS covers composition. Even when a supplier won't hand over exact percentages in a spec sheet or a friendly email, they may be required to disclose composition ranges in the SDS itself, since that document exists for safety and handling purposes, not marketing. Ask for the current SDS specifically and read section 3 closely. Sometimes the information you need was sitting in a document you already had, just not the one you asked for.

Ask for ranges instead of exact numbers

If a supplier won't give an exact percentage, most will give a range, like "5 to 10%" for a given component. A range is genuinely useful for a notification, since concentration or concentration range is explicitly an acceptable way to declare an ingredient. It's less precise than an exact figure, but it's honest and it's usable. Push for the tightest range they're willing to commit to, since a range like "1 to 50%" is barely more informative than no data at all, and a reviewer may reasonably ask you to go back and get something tighter.

Consider a mutual NDA

For a supplier relationship that matters to your business, a non-disclosure agreement covering exact formula percentages can unlock real numbers without the supplier feeling like they've handed their recipe to the open market. This works best when you're a meaningful customer or a growing one, since the supplier has an incentive to keep you happy. It's more friction than a phone call, but it's a normal part of doing business with specialty ingredient houses, and most have a template ready because they've done this before with other customers.

Do the blend expansion math once you have numbers

Once you have real percentages or ranges for the blend's internal components, you still need to carry them through to your finished product. Multiply the component's percentage within the blend by the blend's use level in your formula. If a supplier's "repair complex" is 8% of a named peptide and you're using that blend at 2% in your finished lotion, the peptide's real concentration in the finished product is 8% times 2%, which is 0.16%. This step is where a lot of paperwork errors creep in, because it's easy to accidentally notify the blend's internal percentage instead of the finished-product percentage.

Scenario	What you need	What you do with it
Supplier gives exact percentages	Component % within blend	Multiply by blend use level in your formula
Supplier gives a range	Range for component %	Multiply both ends of the range by blend use level
Supplier gives neither, but SDS section 3 has data	Range or approximate % from SDS	Use as your best available disclosure, document the source
Supplier gives nothing usable at all	Consider an NDA, or a different supplier	Do not guess a number for a filing

When you truly can't get anything

If a supplier stonewalls completely, with no SDS composition data, no range, and no willingness to sign an NDA, that's a signal to think hard about whether this is a supplier you can keep using for a notified product. A finished product notification depends on you actually knowing what's in it. If you can't get that information through any reasonable channel, sourcing an alternative blend or ingredient, even a less exciting one, from a supplier who will document composition is usually the safer long-term choice for your business.

This is a place where having a system track your supplier documentation pays off, because you'll hit this same standoff again with a different supplier eventually. Cosmetic Comply's ingredient matching is built to expand supplier blends and carry percentages through to the finished product automatically once you have the underlying numbers, which takes the manual multiplication error out of the process entirely.