Dehydroacetic Acid Preservative Limits in Practice

Dehydroacetic acid shows up in more formulas than people realize, usually tucked inside a preservative blend with a friendlier-sounding trade name. It is a real, restricted ingredient with its own limit on the Cosmetic Ingredient Hotlist, and because it almost never appears in a formula on its own, the math around it is where a lot of first-time filers stumble.

What it is and why formulators reach for it

Dehydroacetic acid (often listed alongside its salt form, sodium dehydroacetate) is an antifungal and antibacterial preservative. It is popular in "gentler" or naturals-adjacent preservative systems because it pairs well with organic acids like benzoic acid or sorbic acid, letting a formulator hit broad-spectrum protection at a lower total preservative load than using a single preservative at a higher dose.

That popularity is exactly why it needs careful tracking. It rarely arrives in your raw materials list under its own name. It arrives as one line item inside a blend, at a fraction of the blend's total percentage.

The concentration math, worked through

Say a preservative blend is sold at a 20% dehydroacetic acid content, and your formula uses that blend at 0.8% of the finished product. The actual dehydroacetic acid concentration in your finished lotion is:

0.8% x 20% = 0.16%

That is the number that has to sit under the Hotlist limit, not the 0.8% blend usage rate and not the 20% figure on the supplier's technical sheet in isolation. Filers who report the blend's usage percentage as if it were the restricted ingredient's percentage are either overstating their risk (rarely a problem, since it usually just means a stricter-looking filing than reality) or understating it, which is the version that actually causes trouble.

Where this goes wrong on a CNF

On the Cosmetic Notification Form, ingredients are listed by INCI name with a concentration or a concentration range. If your raw materials sheet only shows the branded preservative blend, you need to break it apart before it goes on the notification. Two mistakes show up constantly:

• Filing the blend as one INCI entry. A blend is not an INCI name. It has to be expanded into its actual components, dehydroacetic acid, sodium dehydroacetate, water, and whatever else the supplier's blend contains, each with its own real percentage.
• Using the blend's supplier percentage instead of the finished-product percentage. The 20% figure describes the blend itself. It is not what goes on your CNF. What goes on the CNF is the 20% multiplied by your use rate.

A quick reference

Item	What it is	Filing note
Dehydroacetic acid	Antifungal/antibacterial preservative, restricted on the Hotlist	List by INCI name with the finished-product concentration
Sodium dehydroacetate	Salt form, often co-present in blends	Track separately if the supplier documentation lists it as a distinct component
Preservative blend (trade name)	Not an INCI name	Must be expanded into components before filing; never filed as a single line
Finished-product percentage	Blend use rate x component percentage in blend	This is the number checked against the Hotlist limit

Practical steps before you file

Pull the supplier's technical data sheet or safety data sheet for any preservative blend. Section 3 of an SDS lists composition, and that is where you will usually find the actual dehydroacetic acid content of the blend, if the supplier discloses it. If the SDS is vague or the supplier will not share the breakdown, ask directly. You cannot file an accurate concentration for an ingredient you cannot see.

Once you have the real percentage, check it against the current Hotlist entry for dehydroacetic acid, since Hotlist limits are tied to a specific date of publication and can shift. Do not rely on a limit you remember from a formula you filed a year ago.

This is also a good moment to check whether other restricted ingredients are riding along in the same blend. Preservative systems often stack two or three actives together, and a filer who checks only the ingredient they were looking for can miss a second restricted component sitting in the same bottle.

If pulling apart blends by hand feels like the slow part of every filing, that is essentially the first thing Cosmetic Comply automates. It expands supplier blends into their real INCI components, carries the percentages through the math, and screens each resulting ingredient against the current Hotlist before a human reviewer signs off. It will not replace reading your supplier's documentation carefully, but it takes the arithmetic and the lookup out of your hands on filing day.