Sodium Lauryl Sulphate

Talk to many health-conscious consumers today about personal care products and one of their main topics of concern is use of the allegedly dangerous shampoo ingredient, sodium lauryl sulfate. But is sodium lauryl sulfate truly dangerous or has it received a bad rap? Or does the answer lay somewhere between these two extremes?

This is not an inconsequential question, since our recent marketplace review of more than 100 leading brands of shampoos indicates that most contain this ingredient. The reason sodium lauryl sulfate is used, we believe, is because it is an inexpensive detergent and makes mixtures foam well.

All shampoos are irritating. Shampoos rank among the products most often reported to the Food and Drug Administration for association with scalp irritation, stinging eyes, and tangled, split, and fuzzy hair. Most shampoos contain synthetic detergents for washing hair. But is sodium lauryl sulfate the culprit when it comes to irritation?

What Science Says About Sodium Lauryl Sulfate

In its final report on the safety of sodium lauryl sulfate, the Journal of the American College of Toxicology notes that this ingredient has a “degenerative effect on the cell membranes because of its protein denaturing properties.” What’s more, the journal adds, “high levels of skin penetration may occur at even low use concentration.”

Interestingly, sodium lauryl sulfate “is used around the world in clinical studies as a skin irritant,” notes the journal. The publication expressed additional concerns:Carcinogenic nitrosamines can form in the manufacturing of sodium lauryl sulfate or by its inter-reaction with other nitrogen-bearing ingredients within a formulation utilizing this ingredient.

  • Other studies have indicated that sodium lauryl sulfate enters and maintains residual levels in the heart, liver, lungs and brain from skin contact. This poses the question whether it could be a serious potential health threat from its use in shampoos, cleansers, and toothpastes.
  • Still other research has indicated sodium lauryl sulfate may be damaging to the immune system, especially within the skin. Skin layers may separate and inflame due to its protein denaturing properties.
  • Although sodium lauryl sulfate is not carcinogenic in experimental studies, it has been shown that it causes severe epidermal changes in the area it is applied, indicating a need for tumor-enhancing assays.
  • Additional studies have found that sodium lauryl sulfate is heavily deposited on the skin surface and in the hair follicles. Damage to the hair follicle could result from such deposition.
Often, in order to make a shampoo gentle to the eyes, the manufacturer will utilize a combination of anionic surfactants (i.e., detergents) with nonionic detergents. An anionic detergent contains a negatively charged polar group. A nonionic detergent has no polar end. Anionic detergents “display remarkable detergent, emulsifying, and foaming properties.” Nonionics are “generally considered as the mildest of all surfactants” whose use “has been restricted because of poor foaming potential. They serve more often as auxiliary detergents.”

Unfortunately, many of the gentler detergents that may be substituted for sodium lauryl sulfate pose their own health hazards. For example, many companies have begun to use ethoxylated detergents such as sodium laureth sulfate, cocamide DEA or lauramide DEA because they tend to be less irritating.

Consumers can recognize shampoo ingredients containing ethoxylated detergents and related ingredients by looking for the prefix, word, or syllablePEG, polyethylene, polyethylene glycol, polyoxyethylene, eth (as in sodium laureth sulfate), or oxynol.

It should be recognized that shampoos represent such brief, discontinuous use products that are thoroughly rinsed, thus clearly minimizing the risk from sodium lauryl sulfate. It should also be recognized that many people shampoo daily, and we really do not know whether a lot of little exposures to sodium lauryl sulfate are dangerous or not.

Given the lack of adequate research and suggestive evidence, however, you may well believe it might be wise for health-conscious consumers to seek products without sodium lauryl sulfate, especially with regard to young children. Indeed, consumers have the power to choose safe and perhaps even better products without sodium lauryl sulfate. My personal view is; that there is not enough evidence to spend time hunting through the myriad of shampoos on the shelf in effort to avoid SLS.

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