Sodium C14-16 Olefin Sulfonate

What it is

Sodium C14-16 olefin sulfonate is the surfactant that does the sulfates' job in most “sulfate-free” shampoos. It is made by sulfonating alpha-olefins with fourteen to sixteen carbon atoms, which on an industrial scale come from petroleum. The difference from sodium laureth sulfate lies in the bond: in a sulfate the sulfur group hangs off the chain via an oxygen atom, in a sulfonate it sits directly on the carbon. That makes the molecule more stable towards water and acid — and it does not make it milder.

This substance is therefore the best illustration of a confusion that shapes the whole shelf: “sulfate-free” is a statement about a chemical group, not about tolerance. Like the sulfates, sodium C14-16 olefin sulfonate is an anionic surfactant, it cleans vigorously and foams abundantly. It appears in nine of the products listed here, making it the most widespread surfactant in this lexicon.

Why

• Why “low risk”: the substance is barely absorbed through healthy skin, and all the products listed here are rinsed off. The US expert panel assessed it as safe in rinse-off products and limited the amount permitted in products that stay on the skin.
• Why the evidence level is only “C”: these statements come from an industry association's summary of the assessment. The assessment itself was not accessible in the original for this classification. No concentration limits or numerical values are therefore reproduced here — only the substance of the matter.
• The notable finding again concerns an impurity rather than the substance. Sulfonation can produce sultones — ring-shaped by-products that sensitise at very low levels. The sensitisation described in the literature was attributed to these residues, not to the surfactant itself, and separate, very low purity requirements were formulated for them.
• This is the fourth instance of the same pattern in this lexicon, after benzene with carbomer, ethylene oxide with hydroxyethylcellulose and residual enzymes with xanthan. With technically manufactured auxiliaries, the assessment regularly turns not on the substance but on the cleanliness of its manufacture — and that information appears on no ingredient list.
• Irritation rather than allergy: like all vigorous anionic surfactants, the substance strips fat from the skin on frequent contact. For people with dry or already damaged scalp skin, and for occupational users in constant wet work, that is the practically significant point, not the question of an allergy.

When the assessment differs

• Occupational users: repeated contact with surfactant solutions through the day is the real burden in a salon. It comes not from any single substance but from wet work as a whole — gloves and re-fatting creams help more here than any choice made from an ingredient list.
• Damaged skin: anionic surfactants are absorbed considerably more through damaged skin than through intact skin. Inflamed or cracked scalp skin is a different starting position.
• Eyes: anionic surfactants irritate the conjunctiva. With the perm neutraliser and the shampoo, careful rinsing is therefore more than a formality.
• Products that stay on the skin: different standards apply there and use is limited. This classification applies exclusively to rinse-off products.
• The comparison with sulfates has no clear answer. Manufacturer data and individual test methods reach different conclusions about which of the two surfactants irritates more. This classification takes no decision on that — it only records that “sulfate-free” does not answer the question.

Open questions

• Concentration in the actual products: not available. For a primary surfactant that is the most important missing figure in the whole record.
• The sultone content of the raw material used is not known. According to the account available, that is precisely what determines the sensitisation risk.
• The US expert panel assessment could not be checked in the original. That is the reason for evidence level C and the gap a more robust classification would have to close.
• A direct comparison of irritation potential with sodium laureth sulfate under identical conditions was not evaluated here.
• Environmental data: not examined.

Sources for this assessment

• Cosmetics Info (Personal Care Products Council), Eintrag Sodium C14-16 Olefin Sulfonate. Quelle der Angaben zur Herstellung durch Sulfonierung von Alpha-Olefinen, zur geringen Aufnahme über gesunde und deutlich höheren über geschädigte Haut sowie dazu, dass die beobachtete Sensibilisierung geringen Gamma-Sulton-Rückständen zugeschrieben wurde. Darstellung eines Branchenverbands, die eine Bewertung des Cosmetic Ingredient Review zusammenfasst; die Bewertung selbst wurde nicht im Original geprüft. Abgerufen am 13.09.2026.

Related substances

Applies to: Surfactants

• Cetearyl Glucoside — Emulsifier (sugar-based surfactant)
• Cocamide MEA — Foam booster and thickener
• Cocamidopropyl Betaine — Mild surfactant, cleansing
• Coco-Betaine — Amphoteric surfactant

Further substances from the same group for which a long-form assessment already exists.