What Is Laureth-5 Carboxylic Acid?
Laureth-5 Carboxylic Acid is a synthetic ingredient made by linking lauryl alcohol, a fatty alcohol usually sourced from coconut or palm oil, with roughly five units of ethylene oxide, then adding a carboxylic acid group at one end. The result is a mild, water-loving molecule that mixes easily with oils and dirt, helping them lift away when rinsed with water.
The move toward gentler surfactants in the late 1970s and 1980s led chemists to explore ethoxylated fatty alcohols like Laureth-5. Its balanced cleansing power and low irritation profile quickly secured it a place in personal care labs around the world.
Manufacturing starts with purified lauryl alcohol that undergoes controlled ethoxylation to achieve an average of five ethylene oxide units. The intermediate is then reacted with chloroacetic acid to introduce the carboxyl group, followed by neutralization and purification. The finished material is usually supplied as a clear to slightly hazy liquid or paste that dissolves readily in water.
Because it is both mild and versatile, Laureth-5 Carboxylic Acid shows up in many rinse-off and leave-on products such as facial cleansers, micellar waters, body washes, baby shampoos, exfoliating scrubs, sheet masks, lightweight lotions and makeup removers.
Laureth-5 Carboxylic Acid’s Cosmetic Benefits/Uses
In skincare and haircare formulas this ingredient pulls double duty, helping products cleanse effectively while staying pleasantly textured.
- Cleansing: Its surfactant nature loosens oil, sweat and everyday grime so they wash away with water leaving skin and hair feeling fresh but not stripped
- Emulsifying: It helps blend oil and water parts of a formula into a stable mixture which improves consistency, boosts foaming and keeps products from separating during storage
Thanks to its gentle cleansing profile, Laureth-5 Carboxylic Acid is generally well tolerated by most skin types, including normal, oily, combination and sensitive skin. Its mild nature makes it a good choice for baby care formulas as well as adult products that need to feel soft on the skin. Very dry or eczema-prone skin may still prefer richer surfactants blended with moisturizers, as this ingredient alone will not supply added lipids.
The molecule is synthesized from plant-derived lauryl alcohol and petrochemical ethylene oxide, with no animal by-products used at any step, so it is considered suitable for vegans and vegetarians.
No data suggest that topical use poses a risk to women who are pregnant or breastfeeding, yet this is not medical advice. Anyone who is expecting or nursing should ask a healthcare professional before introducing new skincare just to be safe.
Laureth-5 Carboxylic Acid does not cause photosensitivity, so it will not make skin more prone to sunburn. As with any surfactant, avoid getting the product into the eyes where it can sting.
Potential Side Effects/Adverse Reactions
Side effects and reactions to topical Laureth-5 Carboxylic Acid vary from person to person. The points below list potential issues, though most users will not experience them when the ingredient is formulated and used correctly.
- Mild skin irritation in individuals with very reactive skin, usually presenting as temporary redness or tingling
- Dryness or tightness if used in high concentrations or without follow-up moisturizers, especially on already dehydrated skin
- Eye stinging if the cleanser or shampoo accidentally enters the eyes
- Allergic contact dermatitis in rare cases where a person becomes sensitized to the molecule or residual impurities
If you notice any persistent redness, itching or discomfort after using a product that contains Laureth-5 Carboxylic Acid, discontinue use and consult a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Laureth-5 Carboxylic Acid is highly water soluble and rinses away without leaving an oily film, which keeps its pore-clogging potential low. It does not contain heavy fats or waxes that typically trap debris inside follicles, so breakouts are unlikely for most users. People who are prone to acne can generally consider products with this ingredient safe to use, provided the rest of the formula is lightweight and non-occlusive.
Because it is a surfactant, any comedogenic risk usually comes from companion ingredients such as thick oils or butters rather than from Laureth-5 Carboxylic Acid itself.
Summary
Laureth-5 Carboxylic Acid serves mainly as a gentle cleanser and emulsifier. Its balanced structure has a water-loving head and an oil-loving tail, allowing it to surround dirt, excess sebum and makeup so they can be lifted away with a splash of water. The same property lets it bind the oil and water phases of a product, giving formulas a smooth, stable texture.
While not as famous as ingredients like sodium laureth sulfate or cocamidopropyl betaine, it shows up in a steady stream of modern cleansers, shampoos and micellar waters where mildness is a selling point.
Overall safety data are reassuring: irritation is rare, toxicity studies are clean and it is considered non-sensitizing for most skin types. As with any new cosmetic, perform a quick patch test when first trying a product that contains Laureth-5 Carboxylic Acid just to be sure your skin agrees with it.