To Your Health

A. Shampooing by itself should not damage the hair. Shampoos do not attack the hair cuticle like permanent waving, bleaching, and dyeing will, and even these do not ordinarily damage the hair follicle within the scalp. It requires a serious injury to the scalp to destroy the follicle cells.

In February 2003, a report was published in the journal Contact Dermatitis indicating that the major ingredient found in most shampoos, sodium lauryl sulfate, produced skin irritation more often than several other common shampoo ingredients.

SLS is used in many cosmetics, including some so-called "natural" shampoos, but it is not natural. SLS and another considerably milder detergent that sounds like SLS (sodium laureth sulfate, SLES) are found in most skin/hair care products.

There is a lot of misinformation about SLS on Internet Web sites. Claims that SLS causes cancer are not supported by research. This is not to say that SLS is not a potent skin irritant when used in concentrations of more than 1%, and SLS in shampoos is usually 2-5% or higher. But skin irritation is not the same as cancer. Some have voiced concern about SLS and cataracts, but here again there is no hard evidence. Forty-year-old research indicates that SLS can damage the eyes of infants, but this needs to be verified, and with today's stricter ethical standards this research might not even be possible.

Still, these detergents have their uses, though perhaps not in skin or hair care. Drug delivery by topical application to the skin is more attractive than injection, and SLS or SLES combined with other "penetration enhancers" can increase drug transport through the skin by approximately 100-fold without inducing skin irritation.

SLS is a strong detergent, and detergents are more caustic than soap. Soap is considered "natural" since it has been around for thousands of years, while detergents came on the market less than a hundred years ago. Older folks tend to be wary of soap, recalling those hard cakes of lye soap that grandma used for scrubbing everything from laundry to babies. This harsh homemade soap probably contained an excess of lye from imprecise measurement of the ingredients, lye that removed the oil in your skin or hair by changing it into more soap, which made it feel dry. When made correctly, there is no irritating lye left at the end of the soap-making process.

Most commercial bar soap is still made by the same process that grandma used, but to increase profits manufacturers separate out the glycerin, a natural moisturizer, and sell it by itself, replacing it with synthetic additives. Real soap, containing the glycerin, is still available, and there are even recipes for making your own very mild "lye soap" safely at home. These soaps are fine for shampooing as well as general use.

There are many unrecognizable ingredients on a shampoo bottle label, but read the ingredient list and reject those with chemical names or common allergens (lanolin for instance). You should be OK with a couple of chemicals, allantoin and cetyl alcohol, as well as other ingredients that you recognize, such as aloe vera, chamomile, comfrey, cucumber, or lavender extract.