A documentary recently on France 5, Shower gel, sensitive skins: give them up, caused many reactions. We learned that these hygiene products are composed of many irritating molecules, among them Sodium Lauryl Sulfate (SLS or also called sodium dodecyl–sulfateSDS).
SDS is a sulfated surfactant and a powerful detergent. So powerful that SDS is currently used in industrial cleaning of floors and motors. Yes, you read correctly! This doesn’t stop this ingredient from being the principle ingredient of our daily household products (shower gels, shampoos, cleaning gels…).
SDS and other sulfated surfactants are the number one choice of industrials because they are cheap, they lather well and are favorable to the conservation and stability of formulas. We thus find them in the grand majority of cosmetics on the market even though SDS is more and more criticized/put down for its irritating effects on skin.
Irritating effects that well known since SDS is used as the reference of cutaneous irritants by researchers conducting dermatological studies. In fact, it has been more than 3O years since the first study was conducted in the USA proving that SDS is irritating. We can only wonder about the inertia of cosmetic industrials who continue to use molecules known for their harmfulness on skin and used as cleaning agents, in shampoos and shower gels. Let’s be clear on one thing, for us, sulfated detergents must simply be banished from every cosmetic product.
THE EFFECTS OF SULFATED SURFACTANTS ON SKIN
Cutaneous irritating effects starting at a concentration of 0.5%, SDS is extremely irritating from concentrations of 10 to 30%. And some soaps contain concentrations of 30% of SDS….
Like every sulfate surfactant, SDS also provokes stinging sensations especially if it meets the eyes. Stinging sensations that industrials try to diminish by adding molecules said to be less irritating. Rather than removing the source of the problem, it’s better to hide it.
The destructive action of sulfate surfactants can be explained by the fact that they alter the proteins of cutaneous and ocular cell membranes. This leads to inflammatory and immunity reactions: redness, swelling and stinging are the most courant signs of this type of irritation. These molecules also destroy cutaneous lipids, stopping the hydro-lipidic film from fighting against cutaneous dehydration. Sulfate detergents thus strongly dehydrate the skin and explain the pulling feeling of the skin we feel after showering.
While scientific studies showing their harmful effects are multiplying, the defenders of sulfate surfactants explain that these studies show irritations at much more important concentrations than used in cosmetics. However, a study showed that this counter-argument isn’t receivable, since it’s especially the daily and repeated exposure to these molecules that lead to irritations.
SODIUM LAURYL SULFATE AND SODIUM LAURETH SULFATE : DANGEROUS FOR THE BODY …. POUR LE CORPS AUX CANCERS???
Even more preoccupying yet, the effects of sulfate detergents doesn’t stop at the surface of the skin: they are capable of penetrating in the tissues and fixing themselves as residues in zones of the heart, the liver, the lungs or the brain. SDS particularly has “elevated penetration rates that may occur even for small concentrations”.
It’s cousin, SLES – Sodium Laureth Sulfate (obtained by the ethoxylation of SLS) is slightly less irritating than the original molecule. However it is very difficult for the liver to eliminate: its passing in the organism is far longer, its metabolism much harder and energy-demanding, which make its effects on the organs more harmful on the long term. Thankfully SDS in banned from organic cosmetics.
Even more serious, by altering the proteins of the skin, sulfate detergents also open the way for toxic or carcinogenic molecules in our environment. They also let them penetrate deeply into the skin, raising the risks for the organism.
Not only are they toxic for the organs, they disturb hormonal functions. These molecules can attach themselves to receptors of a hormone: estrogen. They mime its effects, they are endocrine disruptors. As such, they participate in raising cancers in woman, called estrogen-dependant such as hormono-dependent breast cancer and uterus cancer. In men, endocrine disruptors are strongly suspected in drastic drops in fertility observed in the past decades.
Meanwhile ethylene dioxide used to transform SLS (SDS) into SLES in also known to be carcinogenic.
Lastly, SDS is particularly harmful to children. Rapidly absorbed by the eyes, it can stay there 5 days. With an absorption rate especially high in children and with harmful effects on proteins, their accumulation can cause serious damage in the development of children’s eyes.
HOW DO I ESCAPE FROM THE SULFATE DETERGENTS IN MY COSMETICS?
As you now know, these molecules are a serious health care problem. Less serious but that should nevertheless be mentioned, they also inconvenience your skin’s and hair’s beauty.
When is SDS is used daily it favours comedo(black heads) by causing a surplus of sebum production on the face and scalp. On top of damaging them, this sulfate detergent makes the skin and hair greasy. It also provokes dry and splitting ends. Finally, when accumulated on the scalp, its damaging action causes hair loss.
Knowing all of this we can legitimately ask ourselves if damages caused by detergents are actually very favorable for industrials since they push consumers to buy even more products to fight against the damage caused to the skin?
In conclusion, sulfate detergents are dangerous: they are harmful to our skin’s beauty and harmful for the environment (since made out of palm oil and not biodegradable). In our next article behind the scenes of cosmetics, we will tell you about all of the other ingredients your should absolutely avoid in shampoos and shower gels.
While we wait for the law banishing sulfate detergents to be adopted (we can’t wait!) we suggest you avoid buying products with one of these molecules in it: Sodium Lauryl Sulfate, Sodium Laureth Sulfate (banned from organic cosmetics) and Ammonium Lauryl Sulfate.
Until then, let’s get rid of the idea that the more a product makes foam the better it cleans! An abundant foam is the sign of a sulfate detergent with its lot of damages for the skin and the organism. So say bye-bye to foam, your skin and your body will thank you. 😉
Source : Journal of The American College of Toxicology
Source : (Lee C H, Kim H W, Han H J, Park C W. « A comparison study of nonanoic acid and sodium lauryl sulfate in skin irritation,« Exog Dermatol 2004;3:19-25) (Marrakchi S, Maibach HI. Sodium lauryl sulfate-induced irritation in the human face: regional and age-relateddifferences. Skin PharmacolPhysiol. 2006;19(3):177-80. Epub 2006 May 4).
Source : Agner T. Susceptibility of atopicdermatitis patients to irritant dermatitiscaused by sodium laurylsulphate. Acta DermVenereol. 1991;71(4):296-300. (A. Nassif, S. C. Chan, F. J. Storrs and J. M. Hanifin. Abstract: Abnormal skin irritancy in atopicdermatitis and in atopywithoutdermatitis. ArchDermatol. November 1994;130(11):1402).
Journal of the American College of Toxicology –Volume 2. Number 7, 1983 – Final Report on the Safety – Assessment of SodiumLauryl Sulfat.
Skin Deep Report. EnvironmentalWorking Group. RevisedOctober 1995.
Green K, M Chapman J, Cheeks L, M Clayton R, Wilson M and Zehir A. « Detergent penetration into young and adult rabbit eyes: Comparative pharmacokinetics– Cutaneous and OcularToxicology, 1987, Vol. 6, No. 2 : Pages 89-107
CássiaComis Wagner R, Joekes I. Hairproteinremoval by sodium dodecyl sulfate. Colloids Surf B Biointerfaces. 2005 Mar 10;41(1):7-14.
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