Cetyl Alcohol: The Single-Chain Fatty Alcohol Thickener

Two ingredients get mixed up constantly in formulation forums: cetyl alcohol and cetearyl alcohol. They sound almost identical, they show up in a lot of the same product types, and plenty of makers use the names interchangeably without realizing they are two distinct substances with two distinct CAS numbers. Worth clearing up before it causes a labeling headache.

What cetyl alcohol actually is

Cetyl alcohol is a fatty alcohol built from a single, uniform 16-carbon chain. Its INCI name is simply Cetyl Alcohol, and its CAS registry number is 36653-82-4. Despite the word "alcohol" in the name, it behaves nothing like ethanol. It is a waxy, white solid at room temperature, insoluble in water, and it does not have the drying or defatting effect that people associate with alcohol on skin. This is one of the most common consumer misconceptions makers have to head off: the "alcohol" in cetyl alcohol is a chemistry class name (a molecule with a hydroxyl group), not a signal that the ingredient will dry out skin the way isopropyl or denatured alcohol can.

Cetyl alcohol vs. cetearyl alcohol

Here is the distinction that matters:

• Cetyl alcohol is a single, defined 16-carbon fatty alcohol (CAS 36653-82-4).
• Cetearyl alcohol is a blend of cetyl alcohol (16-carbon) and stearyl alcohol (18-carbon) chains, typically in varying ratios depending on the supplier. It carries its own separate INCI listing and its own CAS registration, distinct from either component alone.

If your formula uses cetearyl alcohol, you list it as Cetearyl Alcohol on the ingredient declaration, not as "cetyl alcohol" and not broken into its two components. Conversely, if your supplier's spec sheet for a "thickening wax blend" quietly substitutes cetearyl alcohol where your original formula called for straight cetyl alcohol, your finished texture will shift slightly and your ingredient list needs to reflect whichever one you actually used. This is a common source of formula drift when people reformulate based on "similar" raw materials without updating the INCI declaration to match.

What it does in a formula

Cetyl alcohol shows up in creams, lotions, conditioners, and some lip products for a few overlapping reasons:

• Viscosity and body building. It thickens the oil phase of an emulsion, giving lotions a richer, less watery feel.
• Co-emulsifier support. It is not usually a primary emulsifier on its own, but it stabilizes emulsions when paired with a true emulsifying system, helping prevent phase separation over the product's shelf life.
• Emollience. It leaves a slight, non-greasy softness on skin, which is part of why it is so common in conditioners and body lotions.
• Opacifying effect. In clear or translucent bases, adding cetyl alcohol will typically push the product toward an opaque, creamy appearance.

Typical use levels

Most formulators work with cetyl alcohol somewhere in the 1 to 5 percent range depending on the desired thickness, with hair conditioners sometimes running toward the higher end of that range for slip and detangling feel. These are general formulation norms, not regulatory ceilings. Cetyl alcohol is not currently subject to a Health Canada Hotlist restriction the way some preservatives or UV filters are, but formulators should always verify against the current Hotlist and any market-specific restricted list before finalizing a formula, since these lists are updated periodically.

How it lands on your CNF or ingredient declaration

Detail	Value
INCI name	Cetyl Alcohol
CAS number	36653-82-4
Typical function	Thickener, co-emulsifier, emollient
Typical use level	Roughly 1 to 5%
Known concentration limit	None currently on Canada's Hotlist; confirm current status

When you are filing a Cosmetic Notification Form in Canada, cetyl alcohol goes on the list under its INCI name with your actual formula concentration or the appropriate concentration range. If your product also contains cetearyl alcohol as a separate raw material, both need their own line entries. Do not collapse them into one because they behave similarly.

The bigger habit worth building

This kind of near-duplicate naming problem is everywhere in cosmetic chemistry, not just with fatty alcohols. Sodium PCA versus PCA, tocopherol versus tocopheryl acetate, panthenol versus pro-vitamin B5 marketing language. Building the habit of always tracing a raw material back to its exact INCI name and CAS number, rather than trusting a supplier's product name or a formulation blog's shorthand, will save you from mismatched filings down the line. Tools like Cosmetic Comply are built around exactly that step: taking your ingredient list, resolving each item to its correct INCI and CAS, and flagging anything that needs a second look before it goes into a notification.