If you are a seasoned permanent hair coloring customer, you probably know by now that you should stay away from sulfate shampoos. Why? You’ve probably been told that they can strip color from hair, or that they cause the color to fade. Well, this is not entirely accurate: Yes, sulfate shampoos contribute to color loss but they do not actually ‘strip the color’. Let’s see why.
About the sulfate shampoos
The 2 popular surfactants that people avoid are sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). These surfactants are very effective at cleaning with SLS being stronger. They remove oils very well and heavy build-ups of polymers from hair. That is why they are often included into clarifying shampoos or shampoos for fine hair. Some other versions are the ammonium lauryl sulfate and ammonium laureth sulfate instead of the sodium.
The role of water in color loss
During hair coloring, the large dye polymers form inside the hair. These are trapped inside the hair because of their size. When hair gets soaked into water, the hair shaft will swell. In so doing, the cuticles are forced to open up as well. The dye molecules or fragments are then able to leave the hair.
In other words: water alone can strip color if you wet your hair on a regular basis.
The role of lipids in sealing color
The usual recommendations for those who color hair are to keep the hair conditioned at all times. Why? Because oils/conditioning polymers/butters etc. are hydrophobic: they do not like water. Therefore they prevent too much moisture from entering the hair by acting as a barrier and prevent too much water from leaving the hair as well. They control the rate at which water moves in and out of hair. This job is usually performed by the hair’s natural lipid layer: 18-MEA. During coloring however, that layer is destroyed leaving the hair unprotected. Replenishing with external products is therefore imperative to mimic the behavior of the 18-MEA layer.
Do sulfates actually strip color from hair?
Like I mentioned before, the sulfate shampoos, being great cleaners, will remove those layers of conditioning. More importantly, they will remove the free lipids present in the intercuticular layers. Once the protective hydrophobic layer is gone, water can penetrate hair at its ease. The result: faster color loss. The more damaged the hair, the faster the loss.
True: The sulfate shampoos have an indirect contribution to the color loss. However, they are wrongly accused of extracting the color.
So now you know: water is the major culprit. Sulfates are just the sidekicks aiding it to strip color from hair.
Unfortunately there is no such thing as a ‘color safe’ shampoo. Sulfate-free shampoos do not guarantee that the color will stay in longer. They are only making sure that the cleaning process is mild enough that the fading rate is slower. But as long as water is involved, fading will occur.