Sodium Laureth Sulfate

Sodium laureth sulfate is rated Caution, and the honest description of that rating is that no one has measured it: the comedogenic 3 it carries on the online charts rests on no assay of this material, because no comedogenicity study — rabbit or human — that we could find has ever tested sodium laureth sulfate itself.

What it is

An anionic surfactant: the sulfate ester of an ethoxylated lauryl (dodecyl) alcohol. A short chain of ethylene-oxide units — averaging a low number, commonly one to four, the "laureth" in the name — sits between the fatty alcohol and the sulfate group; commercial SLES is a polydisperse mixture of chain lengths, not one exact molecule. That ethoxylated segment is the whole chemical difference from sodium lauryl sulfate, which has no ethylene-oxide units at all. It is a foaming, oil-lifting detergent, and it is widely used in place of sodium lauryl sulfate in modern facial cleansers, shampoos and body washes, on the grounds that it is gentler on the skin barrier. On a label it is Sodium Laureth Sulfate, sometimes sodium lauryl ether sulfate; SLES in shorthand. There is a naming trap here worth naming, because it is probably where the numbers come from. Sodium laureth sulfate shares the word "laureth" with laureth-4 and laureth-23 — ethoxylated lauryl alcohols that Fulton did test, but which carry no sulfate group — and it shares "lauryl sulfate" with sodium lauryl sulfate, a sulfate that carries no ethoxylation. It is neither of them. It sits between two families and matches neither exactly.

Why we rate it Caution

We rate it Caution at Low confidence, and there is no score behind that rating because no one has produced one. Start with the table nearly every comedogenic list descends from. Fulton's 1989 rabbit-ear survey is unusually complete on surfactants — it scores laureth-4 at 5 and laureth-23 at 3 on its 0–5 scale, along with dozens of other emulsifiers and detergents. Sodium laureth sulfate is not in it. Neither is sodium lauryl sulfate. The single most-quoted comedogenic table in skincare contains neither this ingredient nor its closest relative. The other primary rabbit assay, Morris and Kwan 1983, does reach the relative. It scored sodium lauryl sulfate 0 at 5% aqueous and 0 at 10% aqueous, and ammonium lauryl sulfate 0 at 10%, and its authors wrote in print that their non-comedogenic result "conflicts with the high scores published by Fulton et al." It did not test sodium laureth sulfate. And the earlier Fulton, Bradley, Agueda and Black assay of 1976 — which reaches us through the Cosmetic Ingredient Review's detailed 1983 account of it, not the paper itself — tested sodium lauryl sulfate as well, reporting 3 at 1% and 4 at 5%. It did not test the laureth either. So across the three legacy rabbit assays that touch this corner of the surfactant shelf, every one tested sodium lauryl sulfate or its ammonium sibling, and none tested sodium laureth sulfate. The number that circulates for it — a 3 on CosDNA — is not a reading of this material. We could not trace it to any assay of sodium laureth sulfate, because we could not find one. What the Caution rests on instead is an inference, and we would rather say that than dress it up. The inference is a reasonable one. Sodium laureth sulfate is the ethoxylated, gentler surfactant that displaced sodium lauryl sulfate in most cleansers, and the one head-to-head human study we found supports the "gentler" half of that description. Charbonnier, Morrison, Paye and Maibach, in Food and Chemical Toxicology in 2001, washed forearms with each surfactant and measured subclinical skin-surface damage by squamometry; sodium laureth sulfate produced less than sodium lauryl sulfate. That is an irritation finding, not a comedogenicity finding — the two are different claims — but it is the closest thing to direct evidence about this molecule that we could locate, and it points toward milder, not worse. Combined with the fact that the ingredient is almost always rinsed off within seconds, Caution rather than Clogging is the defensible call. It is a call made in the absence of a measurement, which is why the confidence is Low. And the reason it is Caution rather than Clear is a precautionary one: this is an untested surfactant that still carries a circulating comedogenic number on the consumer charts, and this site holds such an ingredient at Caution rather than issuing a clean Clear it has not earned — while the mildness and rinse-off evidence is what keeps it from anything worse.

What the evidence doesn’t tell you

There is no comedogenicity data on sodium laureth sulfate of any kind. We identified no rabbit-ear score, no human comedone count and no follicular biopsy of this material. Every number attached to it on the consumer charts is an assertion someone typed, not a reading someone took, and we found no sign the ingredient has been put through the assay that would produce one. The one study we found that tested this exact material measured the wrong endpoint for the pore question. Charbonnier and colleagues washed skin and measured surface scaling and subclinical irritation; they did not count comedones or look at follicles. Their result tells you that sodium laureth sulfate is a milder irritant than sodium lauryl sulfate. It does not tell you whether either one clogs pores, because irritation and follicular plugging are different processes, and a study of one is not evidence about the other. We are not going to convert "gentler detergent" into "non-comedogenic." The rinse-off point cuts both ways, and it is worth being honest about the direction. A comedogenicity assay leaves a material on skin for two weeks; sodium laureth sulfate is on a face for seconds before it goes down the drain. Whatever a leave-on assay might find, it would be measuring an exposure that does not resemble how the ingredient is used — which is a reason to distrust any high score such an assay might produce, and equally a reason not to read the absence of a score as a clean bill of health. Neither the number nor its absence has been earned here. The comedogenic question may also be the wrong question for this ingredient, as it is for its relatives. The large and genuinely independent human literature on the lauryl and laureth sulfates is about irritation and barrier disruption, not pores. Whether the irritation a cleanser causes makes acne worse in a given person is a reasonable thing to wonder, and it is not a thing we can cite an answer to. Finally, the field-wide caveat: a 2025 review in JAAD Reviews found that no standardised comedogenicity test exists and that the label "non-comedogenic" is unregulated. It applies to every page here, and with particular force to an ingredient that has no comedogenicity test at all.

Where you’ll see it

Chiefly rinse-off products: foaming facial cleansers, shampoos, body washes and bubble baths, typically among the earlier ingredients, because a primary detergent has to be present at percent-level concentrations to foam and clean. In facial cleansers it is widely used in place of sodium lauryl sulfate, on the "gentler surfactant" grounds described above. These are illustrative categories, not a measured market audit, and a leave-on use would be uncommon.

Sources

Each source says what it actually is. Several widely-cited “sources” for comedogenic ratings are republishing the same 1989 assay, and counting them as independent agreement is how a thin evidence base gets made to look thick.

1. Fulton JE. "Comedogenicity and irritancy of commonly used ingredients in skin care products." J Soc Cosmet Chem 40:321–333 (1989) The 220-row rabbit-ear table nearly every comedogenic score online descends from — cited here chiefly for what it does not contain. It has no sodium laureth sulfate row and no sodium lauryl sulfate row. It does score other ethoxylated lauryl-alcohol surfactants (laureth-4 at 5, laureth-23 at 3, on a 0–5 scale), which is the point: the paper tested materials adjacent to this one and simply never tested this one. It also supplies Fulton's own grade key, which the lists quoting him leave out: a grade of 0 to 1 "is not considered significant," 2 to 3 is "borderline," and 4 to 5 is "considered positive." Method: roughly 10% in propylene glycol, applied to the inner ear of New Zealand albino rabbits, three rabbits per assay, follicles scored for keratosis. Not a source of any score for sodium laureth sulfate — there is none in it.
2. Morris WE, Kwan SC. "Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients." J Soc Cosmet Chem 34:215–225 (1983) A primary rabbit-ear assay, and one of the few legacy papers that openly disagrees with Fulton and says so. Three rabbits, ear canal, 14 applications, microscopic grading, 0–5 scale. It scored sodium lauryl sulfate 0 at 10% aqueous and 0 at 5% aqueous, and ammonium lauryl sulfate 0 at 10%, and its discussion states that its non-comedogenic finding "conflicts with the high scores published by Fulton et al." Cited here to establish material identity: it tested the lauryl sulfate and the ammonium sulfate, not the laureth. It is still a rabbit's ear, not a human face, and not this exact molecule.
3. Cosmetic Ingredient Review Expert Panel. "Final Report on the Safety Assessment of Sodium Lauryl Sulfate and Ammonium Lauryl Sulfate." J Am Coll Toxicol 2(7):127–181 (1983) A safety review of the lauryl (not laureth) sulfates by the Cosmetic Ingredient Review, an industry-funded panel convened by the Personal Care Products Council. Its comedogenicity section describes an experiment — three albino rabbits, internal base of the right pinna, Monday to Friday for two weeks, left ear as control, 0–5 scale — and reports sodium lauryl sulfate at 3 at 1% and 4 at 5%, attributing those numbers to Fulton, Bradley, Agueda and Black, "Noncomedogenic cosmetics," Cutis 17:344 (1976). We have not read the Cutis paper, so those figures are second-hand. Cited here for one purpose: the traceable legacy positive in this surfactant family belongs to sodium lauryl sulfate, at concentration-dependent values, and not to sodium laureth sulfate, which this assessment does not cover. The panel's conclusion also turns on the rinse-off distinction: safe for "discontinuous, brief use followed by thorough rinsing," and not above 1% for prolonged contact.
4. Robinson VC, Bergfeld WF, Belsito DV, et al. "Final Report of the Amended Safety Assessment of Sodium Laureth Sulfate and Related Salts of Sulfated Ethoxylated Alcohols." Int J Toxicol 29(4 Suppl):151S–161S (2010) The CIR's safety assessment that actually covers sodium laureth sulfate itself and its related sulfated ethoxylated-alcohol salts — an industry-funded, independently panelled toxicological review. Cited as the authoritative identity and toxicology source for the exact material: it confirms what SLES is and concludes it safe as used at the reported concentrations, largely on the basis of rinse-off exposure. It assesses irritation, sensitisation and systemic toxicity, not comedogenicity — it carries no comedone count and no follicular measurement — so it is evidence about safety and identity, not about pores.
5. Charbonnier V, Morrison BM Jr, Paye M, Maibach HI. "Subclinical, non-erythematous irritation with an open assay model (washing): sodium lauryl sulfate (SLS) versus sodium laureth sulfate (SLES)." Food Chem Toxicol 39(3):279–286 (2001) The only study we found that tested sodium laureth sulfate itself — and it is an irritation study, not a comedogenicity study. A human open-application washing assay: forearms washed with each surfactant, skin-surface damage read by squamometry (a measure of subclinical scaling and barrier disruption), sensitive enough to separate the two surfactants within three washes. It found sodium laureth sulfate the milder of the two. Genuinely independent of Fulton, and about the right molecule — but the wrong endpoint for the pore question: it measured surface irritation, never a comedone or a follicle. It supports "milder surfactant," which is half the reasoning behind the rating, and it supports nothing about comedogenicity in either direction.
6. "Comedogenicity in cosmeceuticals: A review of clinical relevance, regulatory gaps, and future directions." JAAD Reviews (2025) A recent peer-reviewed review of the whole field, covering the literature from 1972 onward. It is a synthesis of the legacy literature, not a new measurement, and independent of Fulton only in authorship, since the corpus it surveys includes his. It finds that no standardised comedogenicity test exists and that "non-comedogenic" is an unregulated label. Cited for the field-wide caveat.
7. CosDNA ingredient safety/analysis chart A consumer-facing chart that assigns cosmetic ingredients an "acne" number. It lists sodium laureth sulfate at 3. It is not a measurement: the chart gives no assay, no method, no scale definition and no citation for that figure, and no comedogenicity study of sodium laureth sulfate that we could find exists for it to be reporting. Cited only as the source of the number a reader will actually have seen, so the page can say plainly what is behind it: nothing measured that we could trace.

Others in the same family

Surfactants behave similarly enough that the evidence for one is often wrongly read across to the others. These are its structural relatives, not a guess.

• Sodium Lauryl Sulfate Caution Low

Last reviewed 2026-06-24 · How we decide

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