What Is C11-15 Alketh-5?
C11-15 Alketh-5 is a man-made ingredient created by reacting synthetic fatty alcohols that have 11 to 15 carbon atoms with about five units of ethylene oxide. The result is a polyethylene glycol ether that behaves like both oil and water, which is why it is valued in skin care. Chemists began exploring these kinds of alcohol-ethylene oxide blends in the 1960s as safer, more consistent alternatives to natural waxes and soaps. Over time the material found its way into personal care labs because it could keep water-based and oil-based ingredients from separating without adding heaviness or scent.
The manufacturing process starts with lab-made fatty alcohols, which are purified then placed in a reactor with ethylene oxide gas under controlled heat and pressure. After the desired five moles of ethylene oxide attach, the mixture is neutralized, filtered and tested for purity before being shipped to cosmetic formulators.
You will spot C11-15 Alketh-5 in light lotions, face masks, wash-off cleansers, sunscreens, hair conditioners and even color cosmetics like liquid foundations. Any formula that blends oils, silicones or plant butters with a water phase can benefit from its stabilizing power.
C11-15 Alketh-5’s Cosmetic Benefits/Uses
Formulators rely on C11-15 Alketh-5 mainly for its role as an emulsifier, and that single job brings several perks to the finished product.
As an emulsifying agent it helps oil and water stay mixed so the formula looks uniform, feels smooth and delivers active ingredients evenly with each use. A stable emulsion also improves shelf life, reduces the need for extra thickeners and prevents that unappealing layer of separated oil on top of your favorite cream.
Who Can Use C11-15 Alketh-5
C11-15 Alketh-5 is generally well tolerated by all major skin types including oily, dry, combination and normal skin because it sits on the surface and does not meddle with the skin’s natural barrier. Even sensitive skin usually handles it well thanks to its low use level and mild nature, though people with a known history of reacting to polyethylene glycol derivatives may want to proceed with caution.
The ingredient is produced entirely from synthetic fatty alcohols and ethylene oxide so there are no animal sourced components, making it suitable for both vegetarians and vegans.
Current safety data shows no special restrictions for pregnant or breastfeeding women when the ingredient is used topically in cosmetics. That said this is not medical advice and anyone expecting or nursing should confirm all skincare choices with a qualified healthcare professional.
C11-15 Alketh-5 does not cause photosensitivity so it will not make skin more prone to sunburn. It is also fragrance free and non volatile which minimizes the risk of respiratory discomfort when using spray or aerosol formats.
Potential Side Effects/Adverse Reactions
Reactions to any cosmetic ingredient can vary from person to person. The following points outline potential side effects of topical C11-15 Alketh-5 but most users will not experience them when the product is formulated and used correctly.
- Mild skin irritation
- Transient redness or stinging on very sensitive skin
- Allergic contact dermatitis in individuals already sensitized to ethoxylated ingredients
- Eye irritation if the product accidentally gets into the eyes
If you notice any persistent discomfort or visible reaction after applying a product that contains C11-15 Alketh-5 stop using it immediately and consult a healthcare professional.
Comedogenic Rating
Rating: 1/5
C11-15 Alketh-5 earns a low score because it is largely water soluble, used at small percentages and easily rinses off or spreads thinly on the skin so it does not block pores. The molecule also lacks the heavy, waxy backbone that typically triggers congestion. This makes it acceptable for most people who are prone to acne or breakouts.
Keep in mind that the overall formula matters: if C11-15 Alketh-5 appears in a product loaded with rich oils or butters, the blend could still feel heavy on very oily skin even though the emulsifier itself is not pore clogging.
Summary
C11-15 Alketh-5 is an emulsifier that keeps oil and water phases smoothly mixed so lotions, cleansers and makeup stay uniform, spread evenly and last longer on the shelf. It achieves this by positioning its water loving PEG portion in the aqueous phase while its fatty alcohol tail anchors into oils, creating a stable bridge between the two.
It is a behind the scenes workhorse rather than a headline ingredient, showing up quietly in many mainstream and indie formulas where a light feel and reliable stability are needed.
Safety evaluations rate it as low risk for irritation or sensitization when used as directed. Even so skin is personal so patch testing a new product is always a wise move.