What it is

Sodium cocoyl glycinate is made from coconut fatty acids and glycine. It is used in sulfate-free shampoos and facial cleansers as a mild primary or co-surfactant.

How it works

It forms anionic micelles with low skin interaction.

What the studies show

An industry-funded clinical investigation of a glycinate-based body wash found it mild on corneosurfametry and it reduced dryness in the short term. In people with eczema, dryness, rash and itch improved at week 4, and the wash removed 56% of long-wear foundation versus under 30% for two competitors (Regan 2013).
A review gives an overview of shampoo surfactant raw materials and the trend toward sulfate-free systems (Cornwell 2018).

This was a body-wash study, so extrapolating to scalps is an assumption. We found no hair-specific human trial.

Side effects and safety

Irritation was low in the single study, and there are few allergy data.

Bottom line

A promising mild cleanser, similar in role to glutamate and isethionate surfactants, but it needs scalp and hair trials.

Studies 2

Regan J et al. A Novel Glycinate-based Body Wash: Clinical Investigation Into Ultra-mildness, Effective Conditioning, and Improved Consumer Benefits. 2013

Design: rct
Who: healthy adults and people with eczema; body wash, not shampoo

Tested: glycinate-based body wash

Result: Mild on corneosurfametry; reduced dryness in the short term; in people with eczema dryness, rash and itch improved at week 4; removed 56% of long-wear foundation versus under 30% for two competitors. Industry-funded.

Read the study ↗

Cornwell PA. A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments. Int J Cosmet Sci. 2018

Design: review

Result: Overview of shampoo surfactant raw materials, consumer benefits and trends in sulfate-free systems.