What Is Sodium C13-15 Alketh-8 Phosphate?
Sodium C13-15 Alketh-8 Phosphate is a synthetic ingredient made by reacting a blend of mid-length fatty alcohols that have 13 to 15 carbon atoms with ethylene oxide, then treating the resulting alcohol ethoxylates with phosphoric acid and neutralizing the mix with sodium. The result is a water-soluble salt that behaves like a mild detergent. It first appeared in personal care formulas in the late 1970s when chemists were searching for gentler alternatives to traditional sulfates. Because its raw materials can be sourced from either petroleum or plant-derived alcohols, manufacturers can adapt production to meet cost or sustainability goals.
The ingredient is produced in several steps. The C13-15 fatty alcohol blend is fed into a reactor with ethylene oxide to add about eight oxyethylene units per alcohol molecule. This ethoxylated mixture is then phosphorylated, producing phosphate ester groups that are finally neutralized with sodium hydroxide. The process yields a clear to pale yellow liquid that is easy to pump and blend.
Formulators value Sodium C13-15 Alketh-8 Phosphate for its balanced cleansing power and low irritation profile. You will most often see it in facial cleansers, body washes, micellar waters, exfoliating masks, shampoo bases, bubble baths, baby washes, makeup removing wipes and some light lotions that need a bit of rinse-off slip.
Sodium C13-15 Alketh-8 Phosphate’s Cosmetic Benefits/Uses
In skin and hair care formulas this ingredient serves one main purpose.
Sodium C13-15 Alketh-8 Phosphate functions as a cleansing agent. It lowers the surface tension of water so oils, dirt and makeup can lift away more easily during rinsing. Compared with harsher surfactants it creates a softer foam and is less likely to strip skin or hair, helping products feel gentle while still leaving a fresh, clean finish.
Who Can Use Sodium C13-15 Alketh-8 Phosphate
This cleansing agent is generally well tolerated by every skin type including oily, combination, normal, dry and even sensitive or reactive skin because it is milder than many sulfate surfactants and rinses away clean without a squeaky-tight feel. People with very dry or eczema-prone skin may still prefer richer cream cleansers, but the ingredient itself is not considered inherently unsuitable for them.
Sodium C13-15 Alketh-8 Phosphate is typically vegan and vegetarian friendly. Although the starting fatty alcohols can come from either petroleum or plant oils, no animal-derived matter is used in its manufacture and the final salt contains no animal by-products.
Pregnant or breastfeeding women can usually use products that contain this surfactant because it sits on the surface of skin or hair and is washed off, so systemic absorption is negligible. This is not medical advice and anyone who is pregnant or nursing should still show the full ingredient list of any product to a qualified health professional to be safe.
The ingredient does not make skin more prone to sunburn so it is not considered photosensitizing. It is also fragrance free, gluten free, nut free and unlikely to interfere with most actives or preservatives used in modern cosmetic formulas.
Potential Side Effects/Adverse Reactions
Individual responses to topical Sodium C13-15 Alketh-8 Phosphate can vary. The effects listed below are possible yet uncommon when the ingredient is used at normal levels in well formulated products.
- Mild dryness – overcleansing or leaving the product on too long can remove some surface oils and leave skin or hair feeling slightly tight
- Transient stinging – people with compromised skin barriers may feel a brief tingle if the cleanser is in contact with broken or inflamed areas
- Eye irritation – like most surfactants it can cause watering or mild redness if it gets into the eyes before rinsing
- Contact dermatitis – very rare allergic or irritant reactions have been reported, usually presenting as redness itch or small bumps
If any persistent irritation or discomfort occurs stop using the product and consult a healthcare professional.
Comedogenic Rating
Rating: 0 (non-comedogenic)
Sodium C13-15 Alketh-8 Phosphate is a fully water soluble surfactant used almost exclusively in rinse-off products, so it leaves no oily or waxy film that could clog pores. Its molecular structure is designed to lift away sebum rather than sit on the skin, giving it a negligible chance of contributing to comedones.
For these reasons the ingredient is considered suitable for people who are prone to acne or breakouts.
Keep in mind that overall pore-friendliness depends on the whole formulation. If a cleanser pairs this surfactant with heavy oils the finished product could still feel greasy or occlusive even though the surfactant itself is not.
Summary
Sodium C13-15 Alketh-8 Phosphate is a mild cleansing agent that works by surrounding dirt, makeup and excess oil so they can be washed away with water. Its phosphate head attracts water while its ethoxylated fatty tail grabs onto oil delivering an effective yet gentle clean.
Though not as well known as big hitters like sodium laureth sulfate it enjoys quiet popularity among formulators who want balanced foam, mildness and ease of use. You will mainly encounter it in gentle facial cleansers micellar waters and baby products.
The available research supports its safety in rinse-off cosmetics with only a small risk of irritation for very sensitive users. Still, skin can be unpredictable so it is smart to patch test any new product that features this or any other surfactant.