What Is Isopropyl C12-15-Pareth-9 Carboxylate?
Isopropyl C12-15-Pareth-9 Carboxylate is a lab-made ingredient created by linking fatty alcohols from coconut or palm oil (those with 12 to 15 carbon atoms) to polyethylene glycol units, then finishing the chain with an isopropyl ester and a carboxyl group. The result is a silky liquid that blends the softness of plant oils with the water-loving nature of gentle cleansers.
The idea of joining plant-based fats to polyethylene glycol started in the 1960s when chemists looked for lighter, non-greasy skin softeners. Over time the process was refined to give cosmetic chemists a reliable, easy-to-use compound that spreads well, rinses clean and feels smooth on skin. Production begins with purified fatty alcohols, which react with ethylene oxide to add an average of nine oxygen-rich units. A carboxymethyl step adds mild acidity, then isopropyl alcohol finishes the ester end, locking in a balanced texture.
Because it can soften skin without feeling heavy, this ingredient shows up in a wide range of personal care items. You will often find it in daily moisturizers, lightweight facial lotions, hydrating masks, after-sun gels, anti-aging serums and even rinse-off conditioners. Its ability to mix oil and water also helps stabilize creamy cleansers and micellar waters.
Isopropyl C12-15-Pareth-9 Carboxylate’s Cosmetic Benefits/Uses
When formulators add this ingredient to a product they are mainly looking for two related benefits.
- Skin conditioning: It smooths rough patches, boosts softness and leaves a subtle protective film that reduces moisture loss after you towel off or rinse
- Emollient: Its lightweight oil-like feel fills in tiny surface gaps so skin feels supple, comfortable and never greasy, helping lotions glide on evenly while giving a soft after-touch
This silky emollient suits most skin types, including normal, dry, combination and mature skin, because it adds light moisture without leaving a heavy residue. Oily or acne-prone users usually tolerate it as well since it is lighter than classic plant oils, though extremely blemish-prone individuals may prefer to monitor how their skin responds in case any clogging occurs.
The ingredient is made from plant-derived fatty alcohols and synthetic processing steps, so it is generally considered acceptable for vegans and vegetarians. There are no animal-sourced raw materials involved in standard production.
Current safety data show no specific risks for pregnant or breastfeeding women when Isopropyl C12-15-Pareth-9 Carboxylate is used in typical cosmetic amounts. Still, this is not medical advice and anyone who is expecting or nursing should confirm all skincare choices with a healthcare professional.
It does not increase sensitivity to sunlight, so there is no extra need for daytime SPF beyond the usual daily sun-protection habits.
Potential Side Effects/Adverse Reactions
Reactions to topical Isopropyl C12-15-Pareth-9 Carboxylate differ from person to person. The points below list potential issues, but most users will experience none of these when the ingredient is formulated and used correctly.
- Mild skin irritation – rare redness or stinging on very sensitive skin
- Contact dermatitis – uncommon allergic rash in individuals allergic to PEG derivatives
- Temporary eye irritation – possible if a product accidentally gets into the eyes
- Acne flare-up – unlikely but possible in those highly prone to clogged pores
If any discomfort or unusual reaction occurs discontinue use and seek advice from a medical professional.
Comedogenic Rating
Rating: 1 / 5
Isopropyl C12-15-Pareth-9 Carboxylate is built on medium-chain fatty alcohols that have been wrapped in polyethylene glycol. This structure makes the molecule water friendly and less likely to sit in pores like heavier plant oils. Most laboratory and in-use data show little to no pore clogging even at higher use levels, so it earns a low score of 1.
Because of this low rating the ingredient is generally fine for people who are prone to breakouts, though everyone’s skin is different.
Formulas that pair it with heavy waxes or butters can raise the overall clogging risk, so look at the full ingredient list if you are very blemish sensitive.
Summary
Isopropyl C12-15-Pareth-9 Carboxylate is a lightweight emollient and skin conditioner. Its fatty chain slides over rough spots while the PEG portion helps it spread and rinse clean, leaving skin soft without an oily feel.
It shows up most often in everyday face and body lotions, after-sun gels and gentle cleansers. It is not the flashiest ingredient on labels but formulators value it for a silky touch that does not weigh skin down.
Safety studies and decades of cosmetic use point to a very low risk of irritation or allergy for the average user. Still, skin can be unpredictable so it is smart to patch test any new product that contains it.