What Is Ceteareth-4 Phosphate?
Ceteareth-4 Phosphate is a synthetic ingredient made from natural fatty alcohols that come mainly from palm or coconut oil. These fats are first turned into C16-18 alcohols, then reacted with about four units of ethylene oxide, and finally combined with phosphoric acid to form a phosphate ester. The result is a mild, water-loving surfactant with a touch of oil-friendly character, which helps it mix oil and water smoothly.
The use of ethoxylated fatty alcohols in cosmetics took off in the mid-20th century when formulators needed gentler cleansers than traditional soaps. Adding the phosphate group made the molecule even milder and more compatible with skin. Today manufacturers produce Ceteareth-4 Phosphate in large reactors where temperature, pressure and pH are carefully controlled, creating a consistent ingredient that meets cosmetic-grade standards.
You will most often spot Ceteareth-4 Phosphate in facial cleansers, micellar waters, makeup removers, light lotions, scalp treatments and some rinse-off masks. Its ability to lift away dirt and oil without leaving skin tight makes it a favorite in products aimed at sensitive or balanced skin types.
Ceteareth-4 Phosphate’s Cosmetic Benefits/Uses
Ceteareth-4 Phosphate plays a focused but important role in skincare formulas.
Its main function is cleansing. By lowering the surface tension of water it lets the rinse phase slip around oil, makeup, sunscreen and daily grime so they wash away easily. Because its fatty backbone is similar to skin’s own lipids, it tends to feel softer and less stripping than stronger detergents, helping products leave skin clean yet comfortable.
Who Can Use Ceteareth-4 Phosphate
This mild surfactant works for most skin types, including normal, combination, oily and even mildly dry or sensitive skin, because it cleanses without stripping away too much of the skin’s natural oils. Extremely reactive or eczema-prone skin could still find any surfactant irritating if used too often or at high levels, so those users may want to opt for ultra-gentle alternatives.
Ceteareth-4 Phosphate is typically sourced from palm or coconut oil, making it suitable for vegans and vegetarians. A small number of suppliers can start with animal-derived fatty alcohols, so anyone following a strict plant-based lifestyle should check with the brand for confirmation.
Current safety data show no specific risks for pregnant or breastfeeding women when the ingredient is used in rinse-off or leave-on cosmetics at normal concentrations. This is not medical advice and anyone who is expecting or nursing should run any skincare routine past a qualified healthcare professional just to be safe.
The ingredient does not increase photosensitivity, so it will not make skin more prone to sunburn. It is also odorless and free of essential oils or known hormone disruptors, which helps keep the risk profile low.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient vary from person to person. The effects listed below are possible but unlikely for most users when the product is properly formulated and used as directed.
- Mild skin irritation
- Redness or a stinging sensation on very sensitive or compromised skin
- Dryness or tightness if used in a high-foaming cleanser without added moisturizers
- Eye irritation if the product accidentally gets into the eyes
- Allergic contact dermatitis in individuals sensitive to phosphate esters or ethoxylated compounds
If you notice any of these reactions stop using the product and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 1 / 5
Ceteareth-4 Phosphate is highly water-soluble and typically used at low levels in rinse-off products, so it spends little time on the skin and is easily washed away. Its fatty portion is balanced by a phosphate group and several ethylene oxide units, which keeps the molecule too hydrophilic to build up inside pores. Because of this low residue and its mild nature it poses minimal risk of clogging follicles.
For most people, including those prone to acne or breakouts, products containing Ceteareth-4 Phosphate should be well tolerated. Only very oily leave-on formulas that include heavy occlusives alongside it might raise congestion concerns.
Summary
Ceteareth-4 Phosphate is a mild cleansing agent that helps water rinse away oil dirt makeup and sunscreen without stripping skin. It achieves this by lowering surface tension and forming tiny oil-in-water structures that lift grime from the skin’s surface.
While not a headline ingredient like hyaluronic acid or vitamin C it is quietly popular among formulators who need a gentle surfactant for sensitive skin cleansers micellar waters and light lotions.
Current data show it is safe for use at typical cosmetic concentrations with a very low chance of irritation or pore clogging. As with any new skincare product a quick patch test on a small area is a smart precaution before full-face use.