Oleth-23: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Oleth-23?

Oleth-23 is a synthetic ingredient made by reacting oleyl alcohol, which comes from natural fats and oils, with roughly twenty-three units of ethylene oxide. This reaction turns a mostly oil-loving molecule into one that can mix with both oil and water, giving it useful cleansing properties. Chemists first developed the oleth family in the mid-20th century while looking for gentler alternatives to traditional soaps. Over time Oleth-23 became popular in personal care because its balance of oil- and water-friendly parts helps lift away dirt without stripping skin or hair.

Manufacturing starts with purified oleyl alcohol derived from vegetable sources such as olive or sunflower oil. The alcohol is placed in a reactor, then ethylene oxide gas is added under controlled temperature and pressure. Each ethylene oxide unit links onto the alcohol in sequence until the average chain length reaches about twenty-three units, yielding a clear to slightly hazy liquid.

Thanks to its surfactant nature Oleth-23 shows up in many rinse-off and leave-on products. It is common in facial cleansers, body washes, micellar waters, shampoo, makeup removers, exfoliating masks and some lightweight moisturizers where a mild yet effective cleanser is needed.

Oleth-23’s Cosmetic Benefits/Uses

In formulas Oleth-23 serves one main purpose that can make everyday products work better.

Cleansing: Its dual affinity for oil and water allows it to surround makeup, sunscreen, excess sebum and environmental grime, then rinse them away with water. This helps leave skin or hair feeling fresh and comfortable while reducing the risk of residue buildup.

Who Can Use Oleth-23

Oleth-23 is generally well tolerated by normal, oily and combination skin because it rinses clean without leaving a heavy film. People with very dry or highly sensitive skin might notice a tight feeling if the rest of the formula lacks replenishing ingredients since any surfactant can remove some surface lipids.

The ingredient is made from vegetable-derived oleyl alcohol plus synthetic ethylene oxide so it is typically suitable for vegans and vegetarians. Brands that source the starting alcohol from plant oils often label the final product as vegan friendly.

Current safety data do not flag Oleth-23 as a concern for pregnancy or breastfeeding. It is used at low levels in finished cosmetics and does not penetrate deeply into skin. This is not medical advice and anyone who is pregnant or nursing should review products with a healthcare professional before use to be safe.

Oleth-23 is not known to cause photosensitivity so it will not make skin more prone to sunburn. It is also fragrance-free and free of gluten or common food allergens which further broadens its suitability.

Potential Side Effects/Adverse Reactions

Side effects from topical Oleth-23 vary from person to person. The points below outline potential reactions yet most users will not experience them when the ingredient is used correctly in a balanced formula.

  • Transient dryness – over-cleansing or leaving a cleanser on the skin too long can strip moisture leading to a tight or flaky feel
  • Skin irritation – rare stinging or redness can occur in those with compromised or eczema-prone skin barriers
  • Allergic contact dermatitis – very uncommon but possible if an individual develops sensitivity to ethoxylated ingredients
  • Eye irritation – direct contact may cause watering or mild burning so thorough rinsing is advised in eye-area formulas
  • Enhanced penetration of other actives – by disrupting surface oils Oleth-23 can allow stronger actives in the same product to absorb more quickly which could heighten their effect on reactive skin

If any persistent redness, itching or discomfort occurs stop using the product and consult a qualified healthcare provider.

Comedogenic Rating

Rating: 1 / 5

Oleth-23 is a light surfactant that rinses away easily and does not leave an oily film, so the odds of it clogging pores are very low. Formulator data and user feedback rarely link it to breakouts, which is why it sits close to the non-comedogenic end of the scale. It is therefore considered fine for people who are prone to acne or frequent blemishes.

As with any ingredient, the overall formula matters. If Oleth-23 appears alongside thick butters or high levels of heavy oils, those other ingredients could influence pore blockage more than the surfactant itself.

Summary

Oleth-23 works mainly as a cleansing agent, using its balanced oil-loving and water-loving structure to surround grime, sebum and makeup so they can be rinsed away. This action helps skin and hair feel fresh without the harshness linked to some older soaps.

The ingredient shows up in many mainstream cleansers, micellar waters and gentle shampoos, though it is not a buzzworthy superstar. Brands choose it because it is reliable, mild and easy to formulate with rather than for marketing appeal.

Current safety reviews find Oleth-23 to be low risk at the levels used in cosmetics. Serious reactions are rare, yet skin is personal, so patch testing any new product is a smart habit to catch issues early.

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