This study detected the presence of 1,4-dioxane in an industrial product containing the polyethoxylated surfactant SLES. 1,4-dioxane is formed during the production of SLES, by an ethoxylation process, as a toxic and carcinogenic by-product (1).

Sodium laureth sulfate belongs to a group of salts of sulfated ethoxylated alcohols whose safety has been evaluated by the Cosmetic Ingredient Review (CIR) panel for use in cosmetic products. Sodium laureth sulfate can produce skin and eye irritation, but is not a sensitizer. The Panel acknowledged that there are data gaps regarding the use and concentration of these ingredients (2).

This study convincingly found skin irritation caused by Sodium laureth sulfate while another detergent, alkyl polyglucoside, showed no significant reaction (3).

Sodium laureth sulfate is an anionic detergent, which has been used for decades for its foaming power.. However, SLES is somewhat invasive and stimulating to the skin, and many consumers with sensitive skin desire gentler cleansers for everyday skin cleansers. This research finds that the addition of sodium laureth carboxylate and lauryl glucoside to Sodium laureth sulfate, may provide gentle and less aggressive surfactant (4).

For more information:

Sodium Laureth sulfate

References________________________________________________________________________

(1) Saraji, M., & Shirvani, N. (2017). Determination of residual 1, 4‐dioxane in surfactants and cleaning agents using headspace single‐drop microextraction followed by gas chromatography–flame ionization detection. International Journal of Cosmetic Science, 39(1), 36-41.

(2) Robinson VC, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Alan Andersen F. Final report of the amended safety assessment of sodium laureth sulfate and related salts of sulfated ethoxylated alcohols. Int J Toxicol. 2010 Jul;29(4 Suppl):151S-61S. doi: 10.1177/1091581810373151.

(3) Löffler H, Happle R. Profile of irritant patch testing with detergents: sodium lauryl sulfate, sodium laureth sulfate and alkyl polyglucoside. Contact Dermatitis. 2003 Jan;48(1):26-32. doi: 10.1034/j.1600-0536.2003.480105.x. 

(4) Takagi Y, Shimizu M, Morokuma Y, Miyaki M, Kiba A, Matsuo K, Isoda K, Mizutani H. A new formula for a mild body cleanser: sodium laureth sulphate supplemented with sodium laureth carboxylate and lauryl glucoside. Int J Cosmet Sci. 2014 Aug;36(4):305-11. doi: 10.1111/ics.12127.

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Compendium of the most significant studies with reference to properties, intake, effects.

Begum, G., Mohamed, I., Zahoor, H., & Gomaa, R. (2016). A study of potential cytotoxic effect of 1, 4 Dioxane on human hepatic cell line (HEP10).

Abstract. 1, 4 Dioxane is a highly toxic inflammable substance present in contaminated air, tap water and a large variety of products ranging from shampoos, moisturizers to detergents, toothpaste and cosmetics. Canada and Qatar have even banned cosmetics and shampoos that contain 1, 4 Dioxane. This study aimed to investigate the potential cytotoxic effects of 1, 4 Dioxane on human hepatic cell line (HEP10) following exposure to different concentrations; which are 500 ppm, 2000 ppm, 5000 ppm and 10,000 ppm w3wwfor four different durations of time; 1, 7, 14 and 21 days . Cell viability and apoptosis level was assessed for all plates using comparison between MTT Assay and LDHAssay. Lower concentration of 1,4 dioxane has showed relatively high cell toxicity for LDH Assay which wasn’t witnessed in previous studies. MTT Assay’s reliability is questionable for checkingcell viability.

Xu L, Amin S. Microrheological study of ternary surfactant-biosurfactant mixtures. Int J Cosmet Sci. 2019 Aug;41(4):364-370. doi: 10.1111/ics.12541.

Abstract. Objective: The main objective of this paper is to understand the rheological impact of rhamnolipids biosurfactant (mono/dirhamnolipids mixture, CCB) on a common personal care mixed surfactants system: anionic sodium laureth sulfate (SLES) and zwitterionic cocamidopropyl betaine (CAPB). The ternary biosurfactant/surfactants mixtures were evaluated at three different formulation conditions. The experimental results can provide a formulation guideline when applying rhamnolipids in cosmetics and personal care products....© 2019 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

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. 2001 Mar;39(3):279-86. doi: 10.1016/s0278-6915(00)00132-0. 

Abstract. Compared to exaggerated hand washing procedures, an open non-exaggerated assay better approximates consumer surfactant use. Our goal was to observe skin surface modifications induced by an open test with regard to discriminating between surfactant solutions. This human in vivo assay provided information about the effect of only three washes at the laboratory and a week of at-home use. Dorsal hand and volar forearm were compared. The results demonstrated that this clinical model permits exploration of subclinical surfactant-induced irritation. Both the volar forearm and the dorsal hand are capable of discriminating between the effects of sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). Squamometry proved to be a sensitive assessment technique for detecting surfactant-induced subclinical skin surface alterations and for differentiating surfactant effects in this open application assay, in as few as three washes.

Robinson VC, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Alan Andersen F. Final report of the amended safety assessment of sodium laureth sulfate and related salts of sulfated ethoxylated alcohols. Int J Toxicol. 2010 Jul;29(4 Suppl):151S-61S. doi: 10.1177/1091581810373151.

Abstract. Sodium laureth sulfate is a member of a group of salts of sulfated ethoxylated alcohols, the safety of which was evaluated by the Cosmetic Ingredient Review (CIR) Expert Panel for use in cosmetics. Sodium and ammonium laureth sulfate have not evoked adverse responses in any toxicological testing. Sodium laureth sulfate was demonstrated to be a dermal and ocular irritant but not a sensitizer. The Expert Panel recognized that there are data gaps regarding use and concentration of these ingredients. However, the overall information available on the types of products in which these ingredients are used and at what concentrations indicates a pattern of use. The potential to produce irritation exists with these salts of sulfated ethoxylated alcohols, but in practice they are not regularly seen to be irritating because of the formulations in which they are used. These ingredients should be used only when they can be formulated to be nonirritating.