Many people call the skin's response to SLS an allergy, but is it?

An allergy is an immune system response. The immune system sometimes mistakes harmless agents (pollen, animal dander or saliva, some foods, etc.) as potential dangers. It then produces chemicals and sends specialized cells to the 'infected' area to fight off the 'invaders.'

Even the most extreme reaction to sodium lauryl sulfate is not a true allergy, it is a sensitivity. What that means is that your body reacts to a substance, but the immune system is not involved in that reaction. No histamine is produced and no immune cells are sent out.

While this is true, that doesn't mean that SLS and allergy are completely unrelated. It means only that sodium lauryl sulfate allergy is a misnomer.

One of the clinically observed results of sodium lauryl sulfate exposure is that it causes the body to have stronger reactions to other irritants - including allergens.

Because SLS breaks down the skin's barrier, other chemicals and allergens can more easily enter the body. If, for instance, you are allergic to poison ivy and have recently used an sls product, you will likely have a stronger allergic reaction to the poison ivy.

Products which contain sodium lauryl sulfate: shampoo, bubble bath, liquid and bar soap, dishsoap, toothpaste, and some mouthwash.

Because it is derived from coconuts, many companies claim that it is natural, implying that it is gentle and harmless. The government has deemed sodium laury sulfate safe for use in personal care products.

Is it 'gentle' or 'harmless'? The best I can say is that it's not deadly. Sls is used in labs to cause loss of skin integrity. Does that sound gentle? Labs apply sls to skin to break it down. Is that harmless? It should come as no surprise that using skincare products with sls can cause skin damage.

SLS is added to personal care products to give them better foaming qualities - while this is pleasant to experience, many people pay the price.

In sensitive people, SLS can cause canker sores, dry skin, itchy skin and eczema. Even in not-very-sensitive people, SLS can cause dryness and itchiness. In fact, SLS is the most common skin irritant. For sensitive people, it is important to seek out products without sodium lauryl sulfate.

Q: How many people are sensitive to sls?

A: One study showed that 41.8% of 1600 people showed irritant reaction after exposure to 0.5% sls solution.

Q: How is sensitivity to sls affected by the weather?

A: The study (Geier 2003) of 1600 subjects tested over a 5 year period noted what it called 'statistically significant' reduction in sls reactivity during the summer months.

So, for real people, what are the dangers of sodium lauryl sulfate? Based on the cited research, we can assume that nearly half of all people are sensitive to SLS, with most suffering the worst during the winter. Personally, I think that saying sodium lauryl sulfate is dangerous is alarmist.

But the very real effect of this chemical on the skin cannot be ignored. It is damaging and interferes with the body's ability to defend itself from the environment.

Q: How does sls affect individuals with atopic reactions?

A: A study published in 2003 focused on the difference in reactions to sls in the skin of healthy people vs. the reactions to sls in the unaffected skin of people with active atopic dermatitis. They found no significant difference in the reaction to exposure of healthy skin between the two groups, but...

Q: What is the relationship between sls and allergic skin reactions?

A: In laymen's terms, sls intensifies reaction to allergens in allergic individuals.

In a 2003 study (Geier, et al) patients with irritant reactions to SLS showed significantly more reactions to 10 known allergens including fragrances and preservatives.

Additionally, significantly more reactions were observed in SLS-reactive patients to benzoyl peroxide, octyl gallate, cocamidopropyl betaine, Amerchol L-101, tert-butylhydroquinone, and triethanolamine.

Another study (Loffler 2003) investigated the combined effect of topical allergens and irritation on the skin of atopic individuals. In atopic patients, they found increased levels of transepidermal water loss induced by the allergens as well as by sodium lauryl sulphate; when applied consecutively the sls and allergens led to a highly pronounced increase in transepidermal water loss.

Q: What is the relationship between canker sores and sls?

A: In people who have recurrent canker sores, there is much evidence that avoiding oral exposure to sodium lauryl sulfate can significantly reduce the development of ulcerations.

This is true despite the fact that the average exposure time to sls in products such as toothpaste and mouthwash is very short. 1997-Fakhry-Smith S, Din C, Nathoo SA, Gaffar A Found that 96-97 percent of the sls in mouthrinse was expelled within two minutes, and only slightly longer for toothpaste. In 1994, Herlofson BB, Barkvoll P published a study of individuals with recurrent canker sores showing a decrease from a mean of 14.3 incidents of ulceration while using a toothpaste containing sodium lauryl sulfate for three months to a mean of 5.1 when using a toothpaste with no sodium lauryl sulfate for three months. Also, in 1997 Chahine L, Sempson N, Wagoner C A published a 2 month single-blind, crossover study that indicated recurrent canker sores were significantly reduced when toothpaste free of sodium lauryl sulfate ls was used compared to when toothpaste containing sls was used.