Use Level vs the Level Inside Your Raw Material

Here's a mixup I see constantly, and it's an easy one to fall into because both numbers are legitimately called "percentages." There's the percentage of a raw material you weigh into your batch, your use level, and there's the percentage of the actual active substance that raw material contains once it's diluted into your finished product. Those are not the same number, and conflating them is how a formula that looks compliant on paper turns out not to be.

Two different questions

"How much of this raw material am I adding" and "how much of the actual restricted or active substance ends up in my finished product" are related but distinct questions. The first is your use level. The second is what actually matters for checking against a concentration limit, a Hotlist restriction, or an allergen disclosure threshold.

If your raw material is the pure substance itself, water for instance, or plain citric acid, these two numbers are identical. There's no dilution step between what you weigh and what's in the product. But the moment your raw material is a diluted solution, an extract, or a supplier blend, they diverge, and the gap can be large.

Where this shows up most often

Diluted actives

A lot of actives are sold pre-diluted for handling safety or ease of formulating. Retinol, for example, is commonly sold as a 10% or 20% dilution in a carrier oil rather than as the pure substance, because pure retinol is difficult and hazardous to handle directly. If you add 2% of a "10% retinol" raw material to your formula, your actual retinol content in the finished product is 2% x 10%, which is 0.2%, not 2%. Reading your use level as the active's real concentration would overstate it tenfold.

Botanical extracts

A glycerin-based botanical extract might be described as containing the plant material at some ratio, commonly labeled something like a 1:10 extract, meaning one part plant material was used to produce ten parts of the finished extract. The specific marker compounds within that extract, the ones that might carry a restriction or a known allergen, are present at whatever concentration the extraction process yields, which is a manufacturer-specific detail you'd need from their documentation, not something you can infer from the extract's use level alone.

Supplier blends generally

This is the pattern that comes up constantly with fragrance blends, preservative systems, and multi-functional additives. The blend has a trade name, you use it at some percentage, and buried inside it are individual INCI-named components each at their own percentage of the blend. Your use level of the blend tells you nothing on its own about any individual component's real concentration in the finished product. You need the blend's composition breakdown to get there.

The math, stated plainly

Real concentration of a component = (use level of the raw material) x (component's percentage within that raw material)

That's the whole formula. The hard part isn't the arithmetic, it's remembering to apply it every time a raw material isn't the pure substance itself, and getting accurate composition data from your supplier to plug in.

A side-by-side example

Raw material	Use level	Component % within raw material	Real concentration in product
Pure Niacinamide powder	5%	100% (it's the pure substance)	5%
20% Retinol dilution	1%	20%	0.2%
Preservative blend, 3.75% MIT inside	0.5%	3.75%	0.01875%
Fragrance blend, 12% Limonene inside	0.3%	12%	0.036%

Notice how wildly the relationship between use level and real concentration shifts depending on what's actually in the raw material. There's no shortcut that lets you skip asking your supplier for that composition detail.

Why this matters for filing

When you're filing a Cosmetic Notification Form or checking a formula against a restricted ingredients list, what gets screened is the real concentration of each named INCI substance in the finished product, not your use level of whatever raw material happened to deliver it. A formula can look perfectly conservative based on use levels, low percentages across the board, while still carrying a restricted substance over its limit because that substance is concentrated inside one of the raw materials at a much higher rate than the finished-product use level suggests.

Getting the data you need

Ask suppliers directly for the composition or assay percentage of any diluted active, extract, or blend you're using. This is standard information suppliers provide, sometimes on the technical data sheet, sometimes on request, and it's worth building the habit of collecting it for every non-pure ingredient before you finalize a formula, not after.

Cosmetic Comply's ingredient matching does exactly this kind of expansion automatically, taking a raw material's use level and its component composition and carrying the real percentages through to what gets screened against your market's restricted and prohibited lists, so the gap between use level and real concentration doesn't slip through unnoticed.