Sulfates
Sulfates are anion detergents in shampoo that remove sebum from the scalp and hair. The number of sulfates in a shampoo positively correlates to cleansing strength.1 However, sulfates can cause excessive sebum removal and lead to hair that is hard, rough, dull, and prone to tangle and breakage.6 Sulfates also dissolve oil on the hair, causing additional dryness and breakage.7
There are a variety of sulfate compounds with different sebum-removal capabilities. Lauryl sulfates are commonly used in shampoos for oily hair. Tightly coiled hair that has been overly cleansed with these ingredients can become exceedingly dry and unmanageable, which explains why products with lauryl sulfates are avoided. Table 1 includes only 1 product containing lauryl sulfate (Pantene Pro-V Gold Series Shampoo). Patients using a lauryl sulfate–containing shampoo can select a product that also contains a conditioning agent in the formulation.6 Alternatively, sulfate-free shampoos that contain surfactants with less detergency can be used.8 There are no published studies of the cleansing ability of sulfate-free shampoos or their effects on hair shaft fragility.9
At the opposite end of the spectrum is sodium laureth sulfate, commonly used as a primary detergent in shampoos designed for normal to dry hair.10 Sodium laureth sulfate, which provides excellent cleansing and leaves the hair better moisturized and manageable compared to lauryl sulfates,10 is a common ingredient in the products in Table 1 (ApHogee Deep Moisture Shampoo, Pantene Pro-V Gold Series Shampoo, and Pantene Pro-V Truly Relaxed Moisturizing Shampoo).
An ingredient that might be confused for a sulfate is behentrimonium methosulfate, a cationic quaternary ammonium salt that is not used to cleanse the hair, unlike sodium lauryl sulfate and sodium laureth sulfate, but serves as an antistatic conditioning agent to keep hair moisturized and frizz free.11 Behentrimonium methosulfate is found in conditioners and detanglers in Table 1 (The Mane Choice Green Tea & Carrot Conditioning Mask, Kinky-Curly Knot Today, Miss Jessie’s Leave-In Condish, SheaMoisture Raw Shea Butter Extra-Moisture Detangler, Mielle Pomegranate & Honey Leave-In Conditioner). Patients should be informed that behentrimonium methosulfate is not water soluble, which suggests that it can lead to buildup of residue.
Cationic Surfactants and Cationic Polymers
Cationic surfactants and cationic polymers are found in many hair products and improve manageability by softening and detangling hair.6,10 Hair consists of negatively charged keratin proteins7 that electrostatically attract the positively charged polar group of cationic surfactants and cationic polymers. These surfactants and polymers then adhere to and normalize hair surface charges, resulting in improved texture and reduced friction between strands.6 For African American patients with natural hair, cationic surfactants and polymers help to maintain curl patterns and assist in detangling.6 Polyquaternium is a cationic polymer that is found in several products in Table 1 (Carol’s Daughter Black Vanilla Moisture & Shine Sulfate-Free Shampoo, OGX Nourishing Coconut Milk Shampoo, ApHogee Deep Moisture Shampoo, Pantene Pro-V Gold Series Shampoo, Neutrogena Triple Moisture Silk Touch Leave-In Conditioner, Creme of Nature Argan Oil Strength & Shine Leave-in Conditioner, and John Frieda Frizz Ease Daily Nourishment Leave-In Conditioner).