C12-16 Alketh-6 Phosphate: 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 publicly available nomenclature standards and reference materials from The Personal Care Products Council (PCPC) and the European Commission's CosIng database. Our analyses are based on technical data from these sources to ensure accuracy and reliability.

What Is C12-16 Alketh-6 Phosphate?

C12-16 Alketh-6 Phosphate is a synthetic surfactant made by linking medium-chain fatty alcohols (with 12 to 16 carbon atoms) to roughly six units of ethylene oxide, then attaching phosphoric acid to form phosphate esters. The result is a clear to slightly hazy liquid that mixes readily with both water and oil.

The ingredient emerged in the 1960s when chemists searched for milder alternatives to traditional soaps. Originally listed as C12-16 Pareth-6 Phosphate, it was renamed to align with updated cosmetic naming rules yet its safety record and performance have stayed the same.

Production starts with plant-derived or petroleum-based fatty alcohols that are reacted with ethylene oxide under controlled heat and pressure. The ethoxylated alcohol is then treated with phosphoric acid, and the resulting acidic mixture can be neutralized with sodium or potassium hydroxide to improve water solubility. Strict purification steps remove excess reactants and by-products so only the desired phosphate esters remain.

You will most often find C12-16 Alketh-6 Phosphate in gentle facial cleansers, micellar waters, makeup removers, shampoos, body washes, exfoliating masks, lightweight lotions, sunscreens and fluid serums where it boosts cleansing power while keeping the formula smooth and stable.

C12-16 Alketh-6 Phosphate’s Cosmetic Benefits/Uses

This ingredient offers two main benefits that make it a versatile choice for modern formulations:

  • Cleansing – Its surfactant nature lifts away sebum, pollution and makeup without stripping the skin or hair. The molecule’s phosphate group helps create a soft creamy lather and leaves a fresh after-feel
  • Emulsifying – It acts as a bridge between oil and water meaning creams and lotions stay mixed, feel light and spread evenly. This stabilizing effect lets brands blend nourishing oils with watery humectants in a single uniform product

Who Can Use C12-16 Alketh-6 Phosphate

Most skin types including normal, oily, combination and even sensitive skin generally tolerate this mild phosphate surfactant well because it cleanses without a harsh stripping effect. Very dry or barrier-impaired skin might feel a touch tight if the formula is strong or used too frequently so pairing it with replenishing moisturizers is wise.

The ingredient is synthetically produced from plant-derived or petroleum-based fatty alcohols and contains no animal by-products making it suitable for vegans and vegetarians. Check with the individual brand if you need confirmation that every raw material in the finished product is sourced without animal testing or derivatives.

C12-16 Alketh-6 Phosphate has no known hormonal activity and absorbs minimally through intact skin so products containing it are generally considered safe for pregnant or breastfeeding women. This is not medical advice and anyone who is expecting or nursing should show their skincare routine to a qualified doctor to be on the safe side.

The molecule does not increase photosensitivity and has no documented interaction with sunlight so there is no special need for extra sun protection beyond the usual daily SPF recommendation.

Potential Side Effects/Adverse Reactions

Responses to topical C12-16 Alketh-6 Phosphate can differ from person to person. The issues listed below are potential effects only; when the ingredient is used at the levels approved for cosmetics most people will not experience them.

  • Skin irritation redness stinging or itching can occur if the formula is highly concentrated or left on the skin for prolonged periods
  • Dryness or tightness occasional removal of natural oils may leave very dry skin feeling dehydrated
  • Eye discomfort in cleansers or shampoos accidental contact may cause temporary stinging or watering
  • Contact dermatitis rare allergic reactions with rash or swelling have been reported in sensitized individuals
  • Interaction with other irritants when combined with strong acids retinoids or exfoliating surfactants overall irritation potential may increase

If any unwanted reaction develops stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1 / 5

C12-16 Alketh-6 Phosphate is a water-compatible surfactant that rinses clean and leaves little residue on the skin. Because it does not stay trapped inside pores or form an occlusive film its likelihood of clogging follicles is very low, hence the rating of 1. Most people who are prone to acne or breakouts can use products with this ingredient without concern, provided the overall formula is lightweight and non-greasy.

As with any cleanser or emulsifier the final comedogenic potential depends on the complete formulation and how thoroughly the product is rinsed off.

Summary

C12-16 Alketh-6 Phosphate works primarily as a gentle cleanser and emulsifier. Its phosphate-bearing head attracts water while its medium-chain tail loves oil, letting it lift away dirt and makeup then keep oil-and-water mixtures stable in lotions, serums and sunscreens.

Though not a household name it shows up steadily in modern micellar waters, gel cleansers, lightweight creams and haircare where formulators want mild cleansing with a smooth skin feel.

Safety data and decades of cosmetic use indicate a low risk of irritation or sensitization for most users. Still, skin can be unpredictable so it is wise to patch test any new product containing this or any other active ingredient before full-face use.

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