C12-13 Alketh-5: 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 24, 2025
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All information on this page is verified using The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is C12-13 Alketh-5?

C12-13 Alketh-5 is an ingredient made by attaching about five units of ethylene oxide to synthetic fatty alcohols that contain 12 to 13 carbon atoms. The result is a clear liquid or soft paste that mixes well with water and oil, making it valuable in skincare and haircare formulas. Chemists began using this class of ingredients in the late 1960s when polyethylene glycol ethers proved reliable for keeping oil and water blended in lotions and creams. Today manufacturers produce C12-13 Alketh-5 through a controlled reaction where ethylene oxide gas is added to purified C12-13 alcohols under heat and pressure. You will most often find it in facial cleansers, body washes, moisturizers, sunscreens, light emulsions like serums, rinse-off hair conditioners and sheet mask essences that need a smooth, uniform texture.

C12-13 Alketh-5’s Cosmetic Benefits/Uses

C12-13 Alketh-5 is valued for a single key role in cosmetics.

As an emulsifying agent it helps oil and water stay mixed, which keeps a formula stable over time. This leads to products that spread evenly, feel pleasant on the skin and deliver their active ingredients consistently from the first use to the last drop.

Who Can Use C12-13 Alketh-5

C12-13 Alketh-5 is generally considered suitable for all skin types including oily, combination, normal and dry skin because it sits in formulas at low levels and does not add oil or heavy residue. Sensitive skin can usually tolerate it as well, though very reactive complexions may prefer minimalist formulas with fewer synthetic emulsifiers.

The ingredient is produced from synthetic fatty alcohols and ethylene oxide, not animal sources, so it is appropriate for vegans and vegetarians.

Current research shows no special concerns for pregnant or breastfeeding women when C12-13 Alketh-5 is applied topically in cosmetic concentrations. This is not medical advice; anyone who is pregnant or nursing should review their skincare routine with a doctor to be safe.

C12-13 Alketh-5 does not cause photosensitivity and will not make skin more prone to sunburn. It also has no known interactions with common active ingredients such as retinoids, vitamin C or exfoliating acids.

Potential Side Effects/Adverse Reactions

Responses to topical C12-13 Alketh-5 vary from person to person. The following points outline potential side effects, yet most users will not notice any problems when the ingredient is used at standard cosmetic levels.

  • Mild skin irritation
  • Redness or stinging on very sensitive skin
  • Eye irritation if the product accidentally gets into the eyes
  • Dry or tight feeling when formulas containing high amounts are used repeatedly

If you experience any discomfort or visible reaction stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 1 out of 5

C12-13 Alketh-5 is a water-soluble emulsifier that does not leave an oily film on the skin. Its molecular structure is too large to slip into pores and it rinses away easily, which keeps the risk of clogged pores low. Because of this it is generally fine for people who are prone to acne or breakouts.

Keep in mind that the overall formula matters. A product packed with heavy oils could still clog pores even if the emulsifier itself is low risk.

Summary

C12-13 Alketh-5 is an emulsifier that keeps oil and water blended so lotions, cleansers and sunscreens stay smooth and spread evenly. It does this by wrapping around oil droplets and helping them stay suspended in water, which stops the formula from separating on the shelf or on your skin.

The ingredient is fairly common in everyday skincare but not as famous as big-name actives. Formulators reach for it when they need a dependable, low-irritation emulsifier at a modest cost.

Safety data show it is well tolerated at the small amounts used in cosmetics with only rare reports of mild irritation. Still, skin can be unpredictable so it is wise to patch test any new product that contains C12-13 Alketh-5 before applying it to the entire face.

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