The co-wash myth

I recently attempted to go natural and was transitioning for a year-more like procrastinating to cut my relaxed hair off. While I was researching how to take care of my dual-textured hair, I came across the method of co-washing. This method is where one will “wash” their hair with conditioner instead of shampoo. This would prevent the natural hair oils from being removed or stripped by the detergents commonly found in shampoos. This seems like a great idea, but used continuously the myth of co-washing can reveal the dirty truth.

Conditioners can contain many components including humectants, glossifiers, lubrucants, reconstructors, surfactants, oils, thermal protectants, acidifiers, sequestrants, antistatic agents, among other ingredients. Shampoos have ammonium lauryl sulfate, sodium laureth sulfate, and sodium dodecyl sulfate. The chemicals listed in shampoos are essential for dirt removal because they surround oil and dirt by forming micelles that bind to the dirt molecules and allow water to rinse them away. This is seen in the scenario of a greasy pot in water that won’t clean itself unless you add dish detergent. This is the oil-removing power of micelles. Water alone cannot remove dirt, oil, or product from the hair and scalp and using conditioner only adds to the problem.

Another scenario is your skin. If you showered with lotion, and every day you applied more lotion and oil and after one week you showered with lotion and water, yes your skin would be soft, but your pores would become clogged, you would develop acne, and your skin may start to feel slimy. You wouldn’t do this to your body and face, why do this to your hair and scalp.

If you continue with the method of co-washing, I advise you wash the hair with shampoo at the least every 2 weeks. Otherwise, you risk product build up which can create a coat impenetrable to water, causing dryness and breakage. For more tips on moisturizing regimens, read “Winterize your hair-treating dry hair” article.



Could you be allergic to your shampoo?

To continue with the theme of itching and scaling scalps, yes you can develop allergies to your shampoo and other hair products. This is called allergic contact dermatitis. Things to look for are dry scaly patches, itching, redness, pus bumps, weeping and oozing on the scalp within 24-48 hours after using a product. If you are experiencing these symptoms after you wash your hair or perform any other chemical process, there is a chance you may be allergic to a substance in the product.

The best way to identify the culprit product is to take a product vacation. Copious rinsing will help remove any excess chemical residue left on the scalp and hair. If your symptoms do not resolve and are persistent or painful seek medical attention. After the symptoms resolve (and if they were mild), add each one of your hair products back into your regimen on a weekly schedule. For example, first add your shampoo, then wait a week and add your conditioner, and follow suit with each styling product. I call this the slow restart method. You may have to find alternative ways to style your hair without the use of your normal regimen of products during this time.

If the symptoms recur after re-entry of a product (the symptoms will return usually within 24-48 hours), try substituting that product for a hypoallergenic (no fragrances or dyes) one. There are many hypoallergenic brands that make hair products as listed below but be cautious manufacturers constantly change their product formulations.  The basics include shampoos, conditioners, and styling products that are functional but may not have all the bells and whistles such as a luxurious lather, all day hold, and fragrances. You can also try natural products but again be cautious because some natural ingredients may cause allergic reactions as well.  Some common hair product allergens and alternatives to those products are listed below:

hair product

As a dermatologist, I frequently see allergic contact dermatitis. Any obvious culprit products or those discovered with the slow restart method are eliminated and product substitutions are made. If a reaction recurs despite substitutions, there may be a chance that the patient has an allergy to a substance common to several hair products. At this time we discuss performing a patch test.  The patch test entails placing strips of paper tape containing 25 to150 of the most common allergens in products (unlike the pinprick allergy test which tests for food and environmental allergens) in your back.  The patch test strips are left on for 48 hours and the back is evaluated for a reaction at 2 days, then again at 5 days and for certain chemicals, at 10 days. For more information on patch testing, visit If there is a positive test the patient then brings in their products and we sit and read and eliminate any products containing the allergens that were positive on the patch test. I also caution while patch testing can be helpful, it can be misleading at times and may not always reveal an answer.

A common misunderstanding is that you cannot become allergic to a product you’ve used for years. You most certainly can. Every product should be subjected to the slow restart method. So remember, product vacation, then slow restart method to see if you can find the culprit.  If you identify the product causing the symptoms, replace it with a similar hypoallergenic product and hopefully the problem will resolve.