What Is Isopropyl C12-15-Alketh-9 Carboxylate?
Isopropyl C12-15-Alketh-9 Carboxylate is a synthetic ingredient created by combining medium-chain fatty alcohols with ethylene oxide, oxidizing the resulting material to form a mild carboxylic acid then esterifying it with isopropyl alcohol. The fatty alcohols in the C12-15 range can come from plant-derived oils such as coconut or palm or from petroleum sources, but by the time the multi-step process is finished the final substance is fully refined and odorless. First introduced in the late 1990s as formulators looked for lighter alternatives to heavier oils, it quickly gained popularity for its silky feel and good skin compatibility. You are most likely to see it listed on the labels of moisturizers, facial lotions, anti-aging serums, makeup primers, sunscreens, leave-on masks and lightweight body creams where it helps create a smooth elegant texture.
Isopropyl C12-15-Alketh-9 Carboxylate’s Cosmetic Benefits/Uses
This ingredient serves one key role in formulas
As an emollient it fills in the tiny gaps between skin cells to leave the surface feeling soft and supple. Because it has a low molecular weight it spreads easily giving products a light non greasy slip that helps them glide over the skin and absorb quickly. This improves user experience, reduces tackiness and can even boost the performance of actives by helping them distribute evenly across the face or body.
Who Can Use Isopropyl C12-15-Alketh-9 Carboxylate
This light emollient works well for most skin types including normal, dry and combination skin since it softens without leaving a greasy film. People with oily or very acne prone skin usually tolerate it too because it has a low tendency to clog pores, though exceptionally oil slick complexions might prefer even lighter alternatives. The ingredient is synthesized from plant based fatty alcohols or petroleum feedstocks, with no animal derived inputs, so it is generally considered suitable for vegans and vegetarians. Current safety reviews show no evidence that topical use poses risks for pregnant or breastfeeding women, but this is not medical advice and anyone expecting or nursing should run their entire routine past a qualified physician. Isopropyl C12-15-Alketh-9 Carboxylate is not known to cause photosensitivity so daytime application alongside sunscreen is fine. It is also fragrance free and typically free of common allergens which further broadens its suitability.
Potential Side Effects/Adverse Reactions
Side effects and reactions to the topical application of Isopropyl C12-15-Alketh-9 Carboxylate can vary from person to person. The points below outline potential issues yet most users will not experience these if the ingredient has been used correctly in a well formulated product.
- Mild skin irritation or stinging in very sensitive individuals
- Transient redness or warmth shortly after application
- Contact dermatitis in those with a specific allergy to the ingredient
- Temporary eye irritation if the product accidentally gets into the eyes
- Clogged pores or breakouts in extremely acne prone skin when used in high concentrations
If any of these reactions occur discontinue use and seek advice from a healthcare professional or dermatologist.
Comedogenic Rating
Isopropyl C12-15-Alketh-9 Carboxylate carries a comedogenic rating of 1. Its molecular structure is branched and lightweight so it spreads in a very thin layer and is readily absorbed rather than sitting on top of the skin and mixing with sebum. In routine concentrations it is unlikely to trap debris in pores yet the fatty acid backbone keeps a small potential for congestion, especially if layered with heavier occlusives or used at very high percentages. For most people prone to acne or breakouts it should be well tolerated, though those with extremely reactive skin may still prefer to monitor how their skin responds. It is also worth noting that finished formulas matter; a low-comedogenic ingredient can feel heavier when blended with waxes, silicones or rich butters.
Summary
Isopropyl C12-15-Alketh-9 Carboxylate is primarily an emollient that slips between surface skin cells, softening and smoothing while giving lotions and serums a light, non greasy feel. By enhancing spreadability it helps active ingredients distribute evenly and boosts the overall sensory profile of a product. Although not as famous as ingredients like dimethicone or squalane it enjoys quiet popularity with formulators who want a silky finish without heaviness, which is why you will often find it in modern moisturizers, sunscreens and makeup primers.
Current research and decades of consumer use show it to be very safe, with low rates of irritation, minimal comedogenicity and no known systemic concerns. Still, skin can be unpredictable so it is always smart to patch test any new product containing this ingredient before applying it to the entire face.