What Is C9-11 Alketh-3?
C9-11 Alketh-3 is a man-made ingredient created by attaching a small amount of polyethylene glycol to a mix of synthetic fatty alcohols that contain nine to eleven carbon atoms. On average three units of ethylene oxide are added during this process, which is why the name ends with the number 3. The fatty alcohol base can come from either petroleum or plant oils, then it is reacted with ethylene oxide in a controlled setting to form the final liquid or waxy substance.
Ethoxylated alcohols like C9-11 Alketh-3 have been used in personal care since the 1960s when chemists were looking for reliable ingredients that could keep water and oil blended together. Over time this material proved stable, easy to manufacture and gentle enough for everyday skin products, leading to its continued use.
You will most often spot C9-11 Alketh-3 in face and body lotions, light creams, serums, rinse-off cleansers, makeup removers, sheet masks and hair conditioners. It is favored in formulas that need a smooth, non-greasy feel without a heavy aftertouch.
C9-11 Alketh-3’s Cosmetic Benefits/Uses
Formulators include C9-11 Alketh-3 to improve the texture and stability of a product, helping it perform consistently every time you use it.
- Emulsifying: It binds together water and oil phases so the cream or lotion stays uniform from the first pump to the last. A well-formed emulsion spreads more evenly on the skin, delivers active ingredients more predictably and resists separation during storage or temperature changes.
Who Can Use C9-11 Alketh-3
C9-11 Alketh-3 is generally considered suitable for all skin types including oily, dry, combination and normal skin. Its mild emulsifying nature means it rarely triggers problems, though people with highly sensitive or compromised skin may feel a slight sting if the formula contains a high level of the ingredient.
The fatty alcohols used are usually sourced from petroleum or plant oils, not animals, so products that rely on C9-11 Alketh-3 are typically acceptable for vegetarians and vegans. Those following a strict lifestyle may still want to confirm the full supply chain with the brand.
No specific warnings exist for pregnant or breastfeeding women. The molecule is large, water soluble and not known to penetrate deeply into the skin. That said this is not medical advice and anyone who is expecting or nursing should review any skincare product with their doctor to be extra safe.
C9-11 Alketh-3 does not make skin more sensitive to sunlight. It can be used day or night without increasing the risk of sunburn. There are also no known conflicts with common actives like vitamin C, retinoids or exfoliating acids, so it fits well into most routines.
Potential Side Effects/Adverse Reactions
Responses to topical C9-11 Alketh-3 vary from person to person. The points below outline potential issues, but they are not likely to occur for the average user when the ingredient is used correctly in a finished product.
- Mild skin irritation such as redness or itching
- Transient stinging on very sensitive or broken skin
- Allergic contact dermatitis in rare cases
- Eye irritation if the product accidentally gets into the eyes
- Temporary dryness or tightness when used at high concentrations
If you notice any of these reactions stop using the product and consult a healthcare professional or dermatologist for guidance.
Comedogenic Rating
Rating: 1/5
C9-11 Alketh-3 is highly water soluble and does not leave a thick, oily film so it rarely blocks pores. Its relatively short fatty chain plus the ethoxylation step make the molecule more hydrophilic, allowing it to rinse off skin easily and stay mostly in the water phase of a formula. Because of this it has a low likelihood of encouraging blackheads or whiteheads.
Suitable for acne-prone or breakout-prone skin
The rating could rise if the final product also contains heavy oils or waxes, so pore clogging potential depends on the whole formula, not just this single emulsifier.
Summary
C9-11 Alketh-3 acts mainly as an emulsifier that keeps water and oil blended, giving creams and lotions a smooth, stable texture and helping active ingredients spread evenly. Its balanced structure lets it sit at the interface of the two phases and hold them together.
While not a trendy spotlight ingredient it is a quiet staple in everyday lotions, cleansers and hair conditioners because it is reliable, gentle and affordable, which keeps it in steady use across the industry.
Safety studies and long-standing use show a wide margin of safety at normal cosmetic levels. Even so every skin is different so patch testing a new product that lists C9-11 Alketh-3 is a smart precaution.