Sodium Lauroyl Sarcosinate
INCI · Sodium Lauroyl Sarcosinate · also Sarkosyl, Sodium Lauroylsarcosinate
How it works
Sodium lauroyl sarcosinate is made by joining lauric acid to sarcosine, an amino acid derivative. That gives an anionic surfactant — the class that produces genuine foam — but with a much gentler profile than the sulfates people associate with foaming cleansers.
The gentleness is structural. Sulfates like SLS are small and aggressive at binding skin proteins, which is what makes them strip lipids and disrupt the barrier. Sarcosinates bind proteins far less readily, so they lift oil and debris while leaving more of the barrier intact. They also work at mildly acidic pH, which matters because a cleanser that forces surface pH upward disturbs the acid mantle regardless of how gentle its surfactant is.
The evidence
Irritation testing consistently places sarcosinates well below sulfates and near the mildest surfactants in use. There is nothing controversial here: this is a well-characterised material with decades of use.
The caveat worth knowing is a manufacturing one rather than a property of the molecule. Sarcosinates can form nitrosamines if a formula also contains nitrosating agents, which is why the material is not combined with them and why suppliers control for it. It is a solved problem rather than an open risk, but it is the reason the ingredient occasionally appears on avoid lists.
Suitability
- All skin types — this is one of the better foaming surfactants for daily use
- Sensitive skin: markedly gentler than a sulfate at equivalent foam
- Anyone who wants lather but reacts badly to SLS or SLES
Concentration
Typically the primary or secondary surfactant in a cleanser, so anywhere from a few per cent up. What matters more is what it is paired with — a mild primary surfactant alongside a harsh secondary is not a mild cleanser.
Conflicts & combinations
None on skin. It is usually blended with a co-surfactant such as coco-glucoside or cocamidopropyl betaine, which improves mildness and foam quality together. If you are trying to work out whether a cleanser is gentle, read the whole surfactant list rather than the first one — the presence of this ingredient is a good sign, not a guarantee.
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Is sodium lauroyl sarcosinate a sulfate?
No. It is an amino-acid-derived surfactant made from lauric acid and sarcosine. The name resembles sodium lauryl sulfate; the molecules and their effects on skin do not.
Is it harsh?
No. Irritation testing places sarcosinates well below sulfates and near the mildest surfactants in use, because they bind skin proteins far less readily.
What is the nitrosamine issue?
Sarcosinates can form nitrosamines if a formula also contains nitrosating agents, so they are not combined with them and suppliers control for it. It is a solved formulation problem, not an open risk.
Does it foam?
Yes — it is anionic, so it produces genuine lather, which is unusual for a surfactant this mild.
How do I tell if a cleanser with it is gentle?
Read the whole surfactant list. A mild primary surfactant paired with a harsh secondary is not a mild cleanser.