Sulfates and Curly/Wavy Hair Guide

Sulfates are the surfactants (cleansing agents) that people in the curly/wavy hair community worry about the most.

What are sulfates and why would someone with curly hair avoid them?

Sulfates are a type of anionic surfactant, which is considered the strongest form of surfactant. They have a negatively charged hydrophilic (water loving) head that attracts positively charged oils and dirt, which are then rinsed off with the water. That’s great if it’s oils you want to remove, and not so great if it’s removing the hair and scalp’s natural protective oils.

This is why curl advocates like Lorraine Massey recommended avoiding sulfates like SLS in her famous book Curly Girl: The Handbook.

Your hair, on the other hand, needs to retain its natural oils to protect it and your scalp. Stripping them away deprives the hair of necessary moisture, amino acids, and antibodies, and makes it look dry, dull, and lifeless.

Another factor is that anionic detergents like sulfates can increase the presence of negatively charged particles in the hair which means frizz!

Are all sulfates bad?

Sulfates remain a complicated and controversial topic in the curly hair community. They aren’t all the same. For example sodium laureth sulfate has a larger hydrophilic head than sodium lauryl sulfate, which makes it gentler.

Lab Muffin discusses why this is in her post on the subject:

The number of units can change, and this changes how the specific type of SLES interacts with everything else: water, oil and other surfactant molecules. Having these ethoxy units means less SLES will wander off on its own (and into your skin) compared to SLS.

She also notes that depending on the formulation, sulfate shampoos can be gentler than sulfate-free shampoos.

As always, the boring truth is that how harsh sulfates are depends on the formulation.

However, wavies and curlies who want to avoid stripping oils from their hair might want to stick with the milder non-sulfate surfactants.