What Is Nonyl Nonoxynol-9 Phosphate?
Nonyl Nonoxynol-9 Phosphate is a synthetic surfactant created by linking nonylphenol with about nine units of ethylene oxide, then adding a phosphate group at one end. The result is a molecule with a water-loving head and an oil-loving tail, which makes it great at lifting dirt and oil from the skin.
The nonylphenol part comes from petrochemical feedstocks, while the ethoxylation and phosphorylation steps take place in controlled factory settings. First, manufacturers react nonylphenol with ethylene oxide gas to build the polyoxyethylene chain. After they reach the desired average of nine units, they treat the mixture with phosphoric acid or phosphorus pentoxide to attach the phosphate group. The finished ingredient is then purified, neutralized, and blended into liquid form for easy use in cosmetic labs.
Surfactants like Nonyl Nonoxynol-9 Phosphate have been around since the mid-20th century, when formulators sought gentler alternatives to soap. As cosmetic science advanced, adding a phosphate group proved to boost solubility and stability in a wider pH range, making the ingredient more versatile. Today you may find it in facial cleansers, micellar waters, makeup-removing wipes, shampoo, body wash, exfoliating gels and some leave-on toners that double as mild cleansers.
Nonyl Nonoxynol-9 Phosphate’s Cosmetic Benefits/Uses
This ingredient brings key cleansing benefits to modern skincare and haircare products.
- Cleansing: As a surfactant, it lowers the surface tension between water and oils. This helps rinse away sebum, makeup, sunscreen and daily grime without the harsh stripping feel of traditional soap. Its balanced hydrophilic and lipophilic profile allows formulators to create clear, stable and effective washes that leave skin feeling fresh and comfortable.
Who Can Use Nonyl Nonoxynol-9 Phosphate
Most skin types can tolerate this surfactant, especially in rinse-off cleansers where it has only brief contact with the skin. Oily and combination skin often appreciate its ability to cut through excess sebum while normal skin benefits from its balanced cleansing power. Very dry or highly sensitive skin may find it a bit too effective, leading to tightness or mild irritation if the formula is not well buffered with moisturizers.
Because Nonyl Nonoxynol-9 Phosphate is fully synthetic and contains no animal derived raw materials it fits vegan and vegetarian lifestyles. As always cruelty-free status depends on the finished brand’s animal testing policies, not the ingredient itself.
No studies link topical use of this ingredient with risks during pregnancy or breastfeeding. It is not absorbed in meaningful amounts when used in wash-off formats. Still this is not medical advice so anyone who is pregnant or nursing should ask their doctor before adding new products to a routine.
The molecule does not make skin more sensitive to sunlight and has no known interactions with common actives like retinol or vitamin C. It works best in washes and micellar waters and is rarely used at high levels in leave-on products.
Potential Side Effects/Adverse Reactions
Individual responses to Nonyl Nonoxynol-9 Phosphate can vary. The effects below are possible but uncommon when the ingredient is used at proper levels in well-formulated cosmetics.
- Temporary redness or stinging on very sensitive skin
- Dryness or tight feeling if overused or left on the skin too long
- Eye irritation if the cleanser accidentally gets into the eyes
- Rare allergic contact dermatitis in people already sensitized to nonylphenol ethoxylates
If you experience any of these issues stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 1/5
Nonyl Nonoxynol-9 Phosphate is a highly water-soluble surfactant that is designed to be rinsed away rather than left sitting on the skin. It does not leave behind oily residues that could clog pores and it is typically used at low percentages in formulas. Because of these factors, the likelihood of it contributing to blackheads or breakouts is minimal.
People who are prone to acne can generally use products containing this ingredient without extra concern, especially when it is in a wash-off cleanser.
Keep in mind that a product’s overall pore-clogging potential depends on the full formula, not one ingredient alone, so always consider the entire ingredient list.
Summary
Nonyl Nonoxynol-9 Phosphate is mainly a cleansing agent that works by lowering surface tension so water can lift away oil, dirt and makeup. Its dual water-loving and oil-loving structure lets it dissolve greasy grime then rinse it off cleanly.
You will spot it most often in facial cleansers, micellar waters and body washes, though it is not as famous as classics like sodium laureth sulfate. Brands choose it when they want a mild yet effective surfactant that stays stable across different pH levels.
Used at proper levels it is considered safe for the vast majority of skin types with only rare reports of irritation. Even so, everyone’s skin is unique so it is smart to patch test a new product that contains this or any other surfactant before applying it to your entire face.