Isopropyl Myristate: A Fast-Spreading Ester Emollient

Rub a lotion between your fingers and if it disappears almost instantly, leaving skin feeling silky rather than greasy, there is a decent chance isopropyl myristate is doing that work. It is one of the most common synthetic esters in cosmetic formulation, and it earns its place mostly through texture, not through any active skin benefit.

What it is and where it comes from

Isopropyl myristate is the ester formed from isopropyl alcohol and myristic acid. Its INCI name is simply Isopropyl Myristate, and its CAS number is 110-27-0. Chemically it behaves like an oil but with a much lower viscosity than a typical carrier oil, which is exactly why formulators reach for it.

You will find it in:

• Lotions and creams, where it improves spreadability without adding heaviness
• Makeup, especially foundations and lipsticks, where it helps pigments disperse
• Deodorants and antiperspirants, where it reduces the white residue other emollients can leave
• Hair conditioners, for slip

Why it spreads the way it does

Isopropyl myristate has a low surface tension and low viscosity relative to natural triglyceride oils. That combination lets it "carry" other ingredients across skin quickly and evenly, which is why it often shows up paired with heavier oils or butters. It cuts the drag of a rich formula and speeds up absorption, at least the sensory feeling of absorption, since a fast-spreading, fast-disappearing texture reads to most people as "absorbed" even when some material is still sitting on the surface.

The comedogenic conversation

This is the part that generates the most questions. Isopropyl myristate has a long-standing reputation in some comedogenicity rating systems as moderately to highly comedogenic, meaning it has been associated with clogged pores and breakouts in certain skin types, particularly acne-prone skin.

A few things worth knowing before you either panic or dismiss this:

• Comedogenicity ratings mostly come from older rabbit-ear assay studies and small human patch tests. They are a useful signal, not a guarantee of how any individual person's skin will react.
• Concentration matters. A formula using isopropyl myristate as a minor slip agent at a low percentage behaves very differently from one using it as a primary emollient at a high percentage.
• It is not restricted or prohibited on the Hotlist. This is purely a formulation and marketing consideration, not a compliance requirement.

What this means for your label and marketing

If you are formulating for an acne-prone or sensitive-skin audience, isopropyl myristate is worth a second look, not because it is regulated, but because your customer base may specifically be checking ingredient lists for it. "Non-comedogenic" claims on packaging are a common area of scrutiny, and including a moderately comedogenic ester while making that claim is the kind of inconsistency that erodes trust fast, even though it is not a compliance violation in the regulatory sense.

Attribute	Detail
INCI name	Isopropyl Myristate
CAS number	110-27-0
Typical function	Emollient, skin conditioning, viscosity reducer
Hotlist status	Not restricted
Comedogenic reputation	Moderate to high in some rating systems

Filing it correctly

On a Cosmetic Notification Form, isopropyl myristate is listed under its INCI name with its concentration or concentration range, same as any other ingredient. There is no special disclosure trigger tied to comedogenicity, since that is a cosmetic performance and marketing issue rather than a safety restriction. Where it does matter is consistency between what you are filing and what you are claiming on the package. If your notification lists it and your label says "won't clog pores," that gap is worth resolving before either goes out the door.

Cosmetic Comply's screening will confirm the INCI and CAS match and check it against the current restricted list, which for this ingredient comes back clean. The comedogenic judgment call, and whatever claims you build around it, stays a formulation decision that is worth making with eyes open.