Isopropyl myristate: comedogenic rating 5/5
Quick answer
Yes - isopropyl myristate is one of the most comedogenic ingredients in cosmetics, rated 5/5. It is a synthetic ester used to make products feel lighter and spread better, and it is a well-documented breakout trigger.
Comedogenic rating
Irritancy rating: 3/5
Functions
Solvent · Synthetic ester
What isopropyl myristate is
Isopropyl myristate (often shortened to IPM) is a synthetic ester made from isopropyl alcohol and myristic acid. Formulators love it because it dissolves other ingredients, reduces greasiness and gives a dry, silky afterfeel - which is why it turns up in so many 'lightweight' and even 'oil-free' products.
It is also used as a penetration enhancer, helping active ingredients cross the outer skin layer. That same ability to slip into the follicle is what makes it a problem for congestion-prone skin.
Why it rates 4-5/5 for clogging pores
Isopropyl myristate sits at the maximum of classic comedogenic scales. In patch-test literature it is such a reliable comedone producer that it has been used as a positive control - a substance researchers deliberately apply to make pores clog for study purposes.
The ester is small and oily enough to enter the follicle readily, where it mixes with sebum and dead skin cells. The result is the fine, sandpaper-like closed comedones that show up on cheeks and forehead a few weeks after starting a new product.
Who should be careful
Acne-prone skin should treat IPM as a top-tier avoid, especially in leave-on products. The catch is that it is rarely the headline ingredient - it hides mid-list in foundations, primers and 'silky' moisturizers, exactly the products people trust most.
If your breakouts are tiny, uniform and rough to the touch rather than deep and inflamed, scan your recent products for isopropyl myristate before blaming your routine as a whole.
Gentler alternatives
Formulas that get slip from dimethicone, squalane or triethylhexanoin tend to be far safer for congested skin. When comparing two similar products, the one without IPM in the first half of the ingredient list is usually the better pick for acne-prone skin.
Commonly found in
- Foundations and primers
- Lightweight 'oil-free' moisturizers
- Facial serums and oils
- Hair serums that touch the face
- Medicated lotions and penetration enhancers
Common questions
Is isopropyl myristate the same as isopropyl alcohol?›
No. Isopropyl alcohol is a drying solvent; isopropyl myristate is an oily ester with no drying effect. They share part of a name and nothing else - IPM clogs pores, while alcohol's issue is irritation, not congestion.
Why is isopropyl myristate in 'oil-free' products?›
Because 'oil-free' usually means no plant or mineral oils, not no pore-cloggers. IPM is a synthetic ester, not an oil, so it passes the marketing filter while still rating 5/5 on the comedogenic scale.
How fast does isopropyl myristate cause breakouts?›
Typically within two to four weeks of daily use - long enough that people rarely connect the new product to the breakouts. Closed comedones and small uniform bumps are the classic sign.
Related ingredients
Coconut Oil
Yes - coconut oil is highly comedogenic. It scores 4-5 out of 5 on published comedogenic scales (the Fulton assay rated coconut butter 4, practitioner lists rate unrefined oil 5) and is one of the most common pore-clogging ingredients found in moisturizers, cleansers and hair care.
Cetyl Alcohol
Mildly - cetyl alcohol rates 2/5, a low-to-moderate risk. Despite the name it is not the drying 'alcohol' in toners; it is a waxy fatty alcohol that thickens and stabilizes creams, and it is well tolerated by most skin, including many acne-prone people.
Lanolin
Rarely - pure lanolin rates only 1-2/5 on published scales, much lower than its rich, greasy feel suggests. The catch: some lanolin derivatives rate up to 5/5, so the family matters more than the word 'lanolin'.
Squalane
No - squalane is about as close to non-comedogenic as an oil gets, rated 1/5 on published scales. It is one of the safest moisturizing oils for acne-prone skin and a common replacement for coconut oil and other heavy plant oils.