What Is Dea-Oleth-5 Phosphate?
Dea-Oleth-5 Phosphate is a surfactant made by attaching about five units of ethylene oxide to oleyl alcohol, then converting the resulting Oleth-5 into a phosphate ester and neutralizing it with diethanolamine. The oleyl alcohol usually comes from plant oils rich in oleic acid such as olive or soybean, giving the ingredient a partly natural origin even though the final material is produced through several controlled chemical steps.
Phosphate-based surfactants have been explored since the mid-20th century as gentle yet effective cleansers for personal care. When formulators looked for options that could work in a wide pH range and pair well with skin, the DEA-neutralized version of Oleth-5 Phosphate gained traction. Its balance of oil-loving and water-loving portions makes it versatile enough for modern rinse-off and leave-on products.
The manufacturing process starts with hydrogenating natural oils to obtain oleyl alcohol. This alcohol is reacted with ethylene oxide to build a short chain of five ethoxy units, improving water solubility. The ethoxylated alcohol is then treated with phosphoric anhydride or phosphorous pentoxide to create a phosphate mono- and di-ester mixture. Finally, diethanolamine is added to neutralize the acidic phosphate, producing a salt that is easier to incorporate into cosmetic bases.
Because it both cleans and stabilizes oil-in-water mixtures, Dea-Oleth-5 Phosphate shows up in facial cleansers, body washes, shampoos, micellar waters, makeup removers, lotions, light creams, self-tanning products and sheet mask serums.
Dea-Oleth-5 Phosphate’s Cosmetic Benefits/Uses
Formulators choose Dea-Oleth-5 Phosphate for two main reasons
- Cleansing: Its surfactant nature lowers the surface tension of water, helping it surround and lift away dirt, excess oil and makeup so they rinse off easily without leaving a heavy residue
- Emulsifying: The molecule sits at the boundary between oil and water, keeping the two phases blended. This stabilizes creams, lotions and serums so they stay smooth and uniform throughout their shelf life
Who Can Use Dea-Oleth-5 Phosphate
Because it is a gentle cleansing and emulsifying agent, Dea-Oleth-5 Phosphate is generally suitable for normal, oily and combination skin. Sensitive skin usually tolerates it well thanks to its mild nature, though very dry or easily irritated skin might feel a little tight if the overall formula is low in moisturizers. Acne-prone users appreciate that it rinses clean without heavy residue, reducing the chance of clogged pores.
The ingredient is sourced from plant oils and contains no animal-derived components, so it aligns with vegan and vegetarian standards as long as the final product also meets those criteria.
Current safety data shows no specific risks for pregnancy or breastfeeding when the ingredient is used as intended in cosmetics, yet this is not medical advice. Anyone who is pregnant or nursing should check with a healthcare professional before adding new products to a routine.
Dea-Oleth-5 Phosphate does not make skin more sensitive to sunlight and can be worn day or night without extra photo precautions.
Potential Side Effects/Adverse Reactions
Reactions to topical Dea-Oleth-5 Phosphate differ from person to person. The issues listed below are possible but uncommon when the ingredient is used correctly in a well-formulated product.
- Mild skin irritation short-lived redness or stinging, more likely on very dry or damaged skin
- Contact dermatitis rare allergic response that can show up as itching, swelling or rash
- Eye irritation temporary burning or watering if the product gets into the eyes
- Dryness or tight feel possible if the cleanser is left on too long or not followed with moisturizer
- Nitrosamine concern the diethanolamine part can form unwanted nitrosamines if the finished formula also contains nitrite preservatives, though reputable manufacturers avoid this by careful formulation
If you notice any of these effects stop using the product and consult a healthcare professional
Comedogenic Rating
Rating: 1/5
Dea-Oleth-5 Phosphate is highly water soluble and designed to rinse away cleanly, leaving minimal residue that could block pores. Its molecular structure is more attracted to water than to skin lipids, so it does not linger on the surface the way heavier oils or waxes do. For these reasons it earns a low comedogenic score of 1, meaning it is very unlikely to trigger blackheads or whiteheads in most users.
Acne-prone or breakout-prone individuals can generally use products containing Dea-Oleth-5 Phosphate without added concern, provided the overall formula is also low in pore-clogging ingredients.
No additional red flags have been noted regarding its potential to worsen acne beyond the standard caution about pairing DEA salts with nitrite preservatives, which reputable brands avoid.
Summary
Dea-Oleth-5 Phosphate acts as both a cleanser and an emulsifier. Its surfactant head lowers water’s surface tension so grime lifts off easily while its balanced oil-and-water segments allow it to sit at the interface of oil droplets, keeping lotions and creams uniform. Though not a headline ingredient, it is a quiet workhorse in face washes, shampoos and lightweight emulsions where gentle cleansing and stability are needed.
Current safety data shows it is well tolerated with only rare irritation or nitrosamine concerns when properly formulated. Overall it is considered safe for regular cosmetic use. As with any new skincare ingredient it is wise to perform a quick patch test the first time you try a product containing Dea-Oleth-5 Phosphate just to make sure your skin agrees with it.