What Is C11-15 Sec-Alketh-12?
C11-15 Sec-Alketh-12 is a man-made ingredient created by attaching about twelve ethylene oxide units to a blend of synthetic secondary alcohols that have carbon chain lengths between eleven and fifteen. The resulting compound is part of the polyethylene glycol (PEG) family of ethers, giving it a strong ability to sit comfortably between oil and water. First gaining popularity in the late 1970s when formulators looked for reliable, cost-effective emulsifiers, it has since become a staple in both skin and hair care.
Production starts with petroleum-derived or plant-based feedstocks that are converted into C11-C15 secondary alcohols. These alcohols undergo an ethoxylation step in which ethylene oxide is added under controlled heat and pressure. The average of twelve ethoxy groups strikes a balance between water-solubility and oil affinity, making the finished material highly versatile.
You will most often spot C11-15 Sec-Alketh-12 on the ingredient list of lotions, creams, sunscreens, makeup removers, cleansing balms, hair conditioners, masks and anti-aging serums where a stable oil-in-water or water-in-oil mixture is needed.
C11-15 Sec-Alketh-12’s Cosmetic Benefits/Uses
In topical products this ingredient serves one main purpose that delivers several user-friendly perks.
As an emulsifier C11-15 Sec-Alketh-12 helps oils blend evenly with water so the formula stays homogenous from the first pump to the last. A stable emulsion feels smoother, spreads more easily and keeps active ingredients distributed evenly across the skin or hair. It also prevents the greasy or watery separation that can shorten a product’s shelf life and spoil the user experience.
Who Can Use C11-15 Sec-Alketh-12
C11-15 Sec-Alketh-12 is generally considered suitable for all skin types including oily, dry, combination and normal because it is used at low percentages and has a gentle, non-occlusive feel. Those with very reactive or compromised skin should keep an eye on the ingredient list since any surfactant-type material can occasionally heighten sensitivity if the formula is not well balanced.
The ingredient is synthetically produced from petroleum or plant-derived feedstocks and contains no animal by-products, making it acceptable for vegans and vegetarians.
No research points to specific risks for pregnant or breastfeeding women when C11-15 Sec-Alketh-12 is applied topically. Its large molecular size limits absorption through intact skin. This is not medical advice and anyone who is pregnant or nursing should still review any skincare routine with a qualified healthcare professional.
C11-15 Sec-Alketh-12 does not cause photosensitivity, so it will not make skin more prone to sunburn. It can be used morning or night, alone or alongside actives like retinoids, acids or vitamin C without known incompatibilities.
Potential Side Effects/Adverse Reactions
Reactions to C11-15 Sec-Alketh-12 differ from person to person. The effects listed below are potential outcomes and are unlikely for most users when the ingredient is properly formulated.
- Mild skin irritation such as redness or itching
- Contact dermatitis in individuals who are specifically sensitized to PEG derivatives
- Transient stinging on application, typically in leave-on products applied to broken or freshly exfoliated skin
- Eye irritation if the product accidentally gets into the eyes
If you notice any of these reactions discontinue use and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 1 out of 5. C11-15 Sec-Alketh-12 is highly water soluble and used at low levels, so it tends to rinse or wear off without clogging pores. Its molecular structure favors staying in the watery phase of a formula rather than sitting inside hair follicles. For these reasons it is generally considered safe for people prone to acne or breakouts. As with any ingredient, the overall formula and how heavily it is applied can influence pore clogging potential.
Summary
C11-15 Sec-Alketh-12 is mainly an emulsifier that keeps oil and water blended so creams, lotions and hair products stay smooth and stable. By sitting at the boundary between the two phases it prevents separation, improves spreadability and helps active ingredients reach the skin evenly. While not the most talked-about name on an ingredient list, it is a quiet workhorse found in countless mainstream and boutique products because it delivers reliable performance at an affordable cost.
Current safety data shows a low risk profile when the ingredient is used as intended in cosmetics. It is non-sensitizing for most people, non-comedogenic and compatible with all skin types. Still, skin can be unpredictable, so it is always smart to patch test a new product before applying it more broadly.