What it is
In the register’s words: “Poly(oxy-1,2-ethanediyl), .alpha.-(1-oxooctadecyl)-.omega.-hydroxy- (100 mol EO average molar ratio).”
- EU register name (INCI)
- PEG-100 STEARATE
- CAS number
- 9004-99-3
What the register lists it for
These are the uses the European Commission’s CosIng register lists for Peg-100 Stearate 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.
- Cleansing surfactant
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The washing ingredients: they let water lift oil, product and dirt off hair and scalp. Shampoos list them near the top; some conditioners hold a little.
Register definition: “Wetting body surfaces, emulsifying or solubilizing oils, and suspending soil (generally, such ingredients contribute to the foaming and lathering properties of cleansing products).”
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.
- Leave-in conditioners 1 label First five names: 0 of 1 Leave-in conditioners without it
- Stylers 1 label First five names: 0 of 1 Stylers without it
- Protein treatments 1 label First five names: 0 of 1 Protein treatments without it
Every label, product by product (3)
- Cantu Ultra Moisture Nourishing Leave-In Conditioner Leave-in conditioner 19th of 37 names
- Aussie Miracle Curls Frizz Free Curl Cream Styler 20th of 25 names
- Curl Junkie Repair Me! Reconstructive Hair Treatment Protein treatment 14th of 22 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 cleansing surfactant ingredients on these labels
- PPG-1 Trideceth-6 15 labels
- Sodium Methyl Cocoyl Taurate 4 labels
- C12-13 Alketh-23 2 labels
- PEG-150 Stearate 2 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.