What it is
The register’s chemical name for it: “Butane-1,3-diol (CAS No. 107-88-0/ EC No. 203-529-7) (R)-(-)-butane-1,3-diol” (CAS No. 6290-03-5/ EC No. 228-532-0).”
- EU register name (INCI)
- BUTYLENE GLYCOL
- CAS number
- 107-88-0 (i), 6290-03-5 (ii)
- EC number
- 203-529-7 (i), 228-532-0 (ii)
What the register lists it for
These are the uses the European Commission’s CosIng register lists for Butylene Glycol in any cosmetic, hair roles first. They say why a maker might add it, not what it does in one formula, and they aren’t a safety rating.
- Humectant
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Holds water in the product and on the surface it touches. Glycerin, honey and aloe are common humectants on curly-hair labels.
Register definition: “Retaining and/or preserving the moisture in a product during use.”
- Fragrance
-
Gives the product its smell or covers an unpleasant one. A label may name each scent ingredient or group them as Fragrance (Parfum).
Register definition: “Imparting an odour or taste. Creating a perceivable pleasant smell and/or masking a bad smell.”
- Solvent
-
Dissolves other ingredients. Water is the most common; some alcohols and glycols carry this role too.
Register definition: “Dissolving other components of cosmetics. Solvents are usually liquids (aqueous and nonaqueous).”
- Viscosity controlling
-
Makes a product thicker or thinner, so a gel holds its shape or a shampoo pours. Gums, cellulose and some salts carry this role.
Register definition: “Increasing or decreasing the viscosity (thickness) of cosmetics.”
- Skin conditioning
-
The register’s broad role for ingredients that keep skin in good condition. On a hair label it often sits beside a hair role, or marks a plant oil or extract.
Register definition: “Maintaining the skin in good condition.”
Where it sits on each label
US labels list ingredients from most to least, except that those at 1% or less may follow in any order. A name near the top is a large part of the formula. A label doesn’t mark where the 1% point falls, so further down, the order says little about how much is in it.
- Shampoos 1 label First five names: 0 of 1 Shampoos without it
- Clarifying shampoos 1 label First five names: 1 of 1 Clarifying shampoos without it
- Rinse-out conditioners 1 label First five names: 0 of 1 Rinse-out conditioners without it
- Deep conditioners 3 labels First five names: 0 of 3 Deep conditioners without it
- Leave-in conditioners 3 labels First five names: 2 of 3 Leave-in conditioners without it
- Stylers 2 labels First five names: 0 of 2 Stylers without it
- Protein treatments 2 labels First five names: 1 of 2 Protein treatments without it
- Heat protectants 1 label First five names: 0 of 1 Heat protectants without it
Every label, product by product (14)
- Giovanni Curl Habit Curl Defining Shampoo Shampoo 24th of 31 names
- Malibu C Un-Do-Goo Shampoo Clarifying shampoo 4th of 16 names
- Aunt Jackie's In Control Moisturizing Softening Conditioner Rinse-out conditioner 29th of 39 names
- Mielle Babassu & Mint Deep Conditioner Deep conditioner 7th of 38 names
- Giovanni Curl Habit Curl Defining Deep Conditioning Hair Mask Deep conditioner 19th of 24 names
- Briogeo Don’t Despair, Repair! Deep Conditioning Mask Deep conditioner 35th of 40 names
- PATTERN Leave-In Conditioner Leave-in conditioner 4th of 43 names
- Mielle Pomegranate & Honey Leave-In Conditioner Leave-in conditioner 4th of 27 names
- Cantu Ultra Moisture Nourishing Leave-In Conditioner Leave-in conditioner 8th of 37 names
- Curlsmith In-Shower Style Fixer Styler 17th of 30 names
- Curlsmith Fragrance-Free Strong Hold Gel Styler 11th of 15 names
- ApHogee Two-Step Protein Treatment Protein treatment 5th of 29 names
- ApHogee Keratin 2 Minute Reconstructor Protein treatment 42nd of 44 names
- Curlsmith Curlshield Cream Heat protectant 15th of 37 names
Each line runs from the first name on a label to the last; a dot is where this ingredient sits. Makers change formulas now and then; if the list on your bottle differs, go by your bottle.
Your next step
Other humectant ingredients on these labels
- Propylene Glycol 22 labels
- Honey 19 labels
- Sorbitol 11 labels
- Sodium Hyaluronate 8 labels
- PCA 5 labels
- Phytantriol 5 labels
- Xylitol 5 labels
- Anhydroxylitol 3 labels
Updated · The name, numbers and uses come from the European Commission’s CosIng entry (CC BY 4.0); we write the uses in US spelling and put the hair ones first. The labels are each maker’s own. The order rule is the FDA’s Cosmetics Labeling Guide. All our sources are on the Sources page.