What Is Undecyleneth-6?
Undecyleneth-6 is a synthetic ingredient made by linking ethylene oxide units to undecylenic acid, a fatty acid that can be sourced from castor oil or other plant oils. The result is a mid sized surfactant molecule with an average of six ethylene oxide units attached, giving it both water loving and oil loving parts. This dual nature lets it mix oils, dirt and water with ease.
The cosmetic industry began turning to undecylenic acid derivatives in the 1950s because of their natural deodorizing and antifungal qualities. Chemists later discovered that adding ethylene oxide made these ingredients milder on skin and easier to blend into lotions and washes, which led to the creation of Undecyleneth-6. Today the compound is produced in large reactors where controlled amounts of ethylene oxide are added to purified undecylenic acid, then refined and tested for skin safety.
You will most often spot Undecyleneth-6 in facial cleansers, micellar waters, clarifying shampoos, scalp tonics, lightweight moisturizers, body washes and some leave-on serums designed for oily or blemish prone skin. Its mix of cleansing power and mild antimicrobial action makes it a versatile choice for formulas that aim to freshen skin without stripping it.
Undecyleneth-6’s Cosmetic Benefits/Uses
Formulators choose Undecyleneth-6 because it performs several helpful jobs in one ingredient
- Anti-Seborrheic: Helps reduce excess oil on skin or scalp which can lessen shine and keep pores from feeling clogged
- Antimicrobial: Discourages the growth of odor causing or blemish causing microbes supporting a cleaner skin environment
- Cleansing: Lifts away dirt makeup and sebum while rinsing off easily so skin feels fresh not tight
- Emulsifying: Stabilizes mixtures of oil and water allowing creams lotions and serums to stay smooth and uniform over time
Who Can Use Undecyleneth-6
Because it removes oil without being overly harsh, Undecyleneth-6 suits normal, oily and combination skin as well as those who are prone to breakouts. Dry or very sensitive complexions can still benefit when the ingredient is blended into a gentle formula, but if your skin already feels tight or flaky you may want to pair it with richer moisturizers to avoid extra dryness.
Undecyleneth-6 is produced from plant based fatty acids and petroleum free ethylene oxide so it contains no animal derived material, making it acceptable for vegans and vegetarians.
There is no evidence that this ingredient is absorbed in a way that would affect pregnancy or nursing. That said this is not medical advice and anyone who is pregnant or breastfeeding should show the product label to a doctor before adding it to their routine just to be safe.
The molecule does not increase the skin’s sensitivity to sunlight and there are no known ingredient conflicts worth noting.
Potential Side Effects/Adverse Reactions
Responses to topical Undecyleneth-6 differ from person to person. The issues listed below are possible yet not expected for most users when the ingredient is properly formulated.
- Temporary dryness or tightness in people who already have low oil levels
- Mild stinging or redness on very sensitive or compromised skin
- Allergic contact dermatitis in the rare case of an individual sensitivity to undecylenic acid derivatives
- Eye irritation if a cleanse off product is not rinsed thoroughly
If you notice any of these reactions stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1 / 5
Undecyleneth-6 is primarily used in rinse-off cleansers and lightweight emulsions where it is well diluted and quickly removed from the skin. Its molecular size and water-soluble ethoxylated chain mean it does not sit inside pores or form a stubborn film, so the likelihood of clogged pores is very low. A rating of 1 reflects this low but not entirely zero risk, as any surfactant can cause dryness that might prompt reactive oil production in some users.
Overall this ingredient is suitable for acne-prone or breakout-prone skin, especially in wash-off formats.
If a product with Undecyleneth-6 is left on the skin, the concentration is typically under 2 percent which still keeps the comedogenic potential minimal. No published studies or dermatologist reports list it as a common pore-clogger.
Summary
Undecyleneth-6 cleanses, reduces surface oil, suppresses problem microbes and stabilizes oil-in-water formulas thanks to its balanced lipophilic fatty tail and six-unit ethoxylated head. This dual nature lets it lift away grime while playing nicely with both watery and oily ingredients.
The ingredient is a quiet workhorse rather than a trendy spotlight additive. It appears in many everyday cleansers and scalp products but rarely headlines marketing claims, so consumers may not recognize the name even though they benefit from its mild effectiveness.
Current safety data and decades of cosmetic use show a very low risk of irritation or systemic impact when the ingredient is used as directed. Still, skin can be unpredictable so performing a small patch test with any new product containing Undecyleneth-6 is a smart precaution.