What Is C13-15 Alketh-21?
C13-15 Alketh-21 is a lab-crafted ingredient made by attaching about 21 units of ethylene oxide to a blend of synthetic fatty alcohols that each contain 13 to 15 carbon atoms. The result is a water-loving, oil-friendly molecule that acts as a bridge between the two, allowing oily grime to mix with water so it can be rinsed away. Early versions of this chemistry showed up in industrial cleaners in the mid-20th century, and formulators soon realized its mildness and efficiency made it ideal for personal care. Today manufacturers start with plant-derived or petroleum-based fatty alcohols, react them with ethylene oxide under controlled heat and pressure, then purify the mixture to cosmetic grade. Thanks to its gentle yet effective nature, you will often spot C13-15 Alketh-21 in facial cleansers, micellar waters, shampoos, body washes, exfoliating masks, make-up removers and some lightweight lotions where it helps keep the formula clear and stable.
C13-15 Alketh-21’s Cosmetic Benefits/Uses
Here is what this multitasker brings to a cosmetic formula:
- Cleansing agent: Its dual affinity for oil and water lifts dirt, excess sebum and makeup without leaving a tight or squeaky feel so skin and hair feel fresh and comfortable
- Solubilizing agent: Helps disperse small amounts of oils, fragrances or active ingredients evenly through a water-based product keeping the formula clear and preventing separation over time
Who Can Use C13-15 Alketh-21
This surfactant is generally gentle enough for all skin types including oily, combination, normal and even many sensitive skins because it cleans without stripping away too much of the natural barrier. Extremely reactive or eczema-prone skin should still proceed cautiously since any surfactant can be a trigger if the barrier is already compromised.
C13-15 Alketh-21 is synthesized from plant or petroleum derived fatty alcohols and does not rely on animal sources, making it suitable for vegans and vegetarians. Finished products may still vary in their overall vegan status depending on other ingredients so label checks are advisable.
Current safety data show no specific risks for pregnant or breastfeeding users when the ingredient is used as directed in rinse-off or leave-on cosmetics. This is not medical advice and anyone who is pregnant or nursing should run any skincare product past a healthcare professional to be on the safe side.
The ingredient does not absorb UV light or make skin more sensitive to sunlight so it is not considered photosensitizing. It is also odorless and nonvolatile which makes it unlikely to aggravate fragrance sensitivities.
Potential Side Effects/Adverse Reactions
Responses to topical C13-15 Alketh-21 can vary from person to person. The issues listed below are only potential outcomes and are uncommon when the ingredient is correctly formulated at standard use levels.
- Mild transient stinging or redness especially on very sensitive or freshly exfoliated skin
- Dryness or tightness if used in a high concentration or in an overly foaming formula
- Contact irritation in individuals with an existing compromised skin barrier
- Allergic contact dermatitis which is rare but possible in people with an ethoxylate allergy
- Eye irritation if the product accidentally enters the eyes during use
If any of these reactions occur discontinue use and consult a healthcare professional for guidance.
Comedogenic Rating
Rating: 1/5. C13-15 Alketh-21 is a lightweight water-soluble surfactant that does not form a heavy film on skin and is typically used at low levels, especially in rinse-off products. Because it is quickly diluted and washed away, it has very little chance to sit inside pores and clog them. For these reasons it earns a low score of 1, meaning it is unlikely to trigger blackheads or breakouts for most users. People who are acne-prone generally tolerate it well, especially when it appears in cleansers rather than leave-on formulas. One point is deducted from a perfect zero since any surfactant can contribute to dryness if overused and very dry skin can in turn overproduce oil, which might indirectly influence blemishes.
Its comedogenic potential can also depend on the overall formula. If paired with heavy oils or waxes the final product could still feel pore-clogging, so always consider the full ingredient list.
Summary
C13-15 Alketh-21 works mainly as a cleansing agent and a solubilizer. Its oil-loving tail grabs onto sebum and makeup while its water-loving head lets those impurities rinse away, leaving skin and hair clean yet comfortable. In watery formulas it also keeps small amounts of fragrance or actives evenly dispersed so the product stays clear and stable.
The ingredient is a quiet workhorse rather than a trending star. You will spot it in everyday cleansers, micellar waters and body washes but it rarely headlines marketing claims, partly because consumers focus more on actives like vitamins or acids.
Current research and decades of use show it to be low risk for irritation or allergy when formulated correctly. Still, everyone’s skin is unique so it is smart to do a quick patch test whenever you try a new product that contains C13-15 Alketh-21, especially if your skin is sensitive or reactive.