Steareth-2 / Steareth-20
Steareth-2, which our list names Steareth-2 / Steareth-20, is rated 2 on our list, in the low band, and the number is traced: Fulton 1989 graded it 2 and Fulton 1989 graded it 2.
Like every rating here, it is for the raw ingredient tested alone, and a label does not print how much of it a product holds.
Is steareth-2 comedogenic?
Steareth-2 is rated 2 on the comedogenic scale, which is the low band.
Common emulsifiers used together to create highly stable, smooth cosmetic creams.
- Comedogenic rating
- 2 out of 5
- Band
- Low: Little plugging in the rabbit-ear test. Fulton 1989 counts 0 to 1 as not significant and 2 as borderline.
- Where the number comes from
- Traced to Fulton 1989. The section on who rated it prints each grade.
- Composition
- Surfactant / Emulsifier / Alcohols & Derivatives
- Also written as
- Steareth-20
What a 2 means in practice
One and two are the low band. In the rabbit-ear test, Fulton 1989 counted 0 to 1 as not significant and 2 as borderline. A low grade on a rabbit's ear, which reacts more readily than human skin, is weak evidence of a problem on a person.
Two things change what this number is worth. Ingredients are listed in descending order of concentration, so steareth-2 near the top of a label matters far more than steareth-2 at the bottom. And the rating describes the raw ingredient on its own. A 2006 review in the Journal of the American Academy of Dermatology found that a rating for a single ingredient does not reliably predict how a finished formula behaves on human skin. The full story of the scale is here.
Who rated it
Our list gives steareth-2 2. These are the figures the published rabbit-ear studies we have read give it, as printed in each paper's table.
| Paper | Grade | Tested as |
|---|---|---|
| Fulton 1989 | Grade 2 | Tested as Steareth-2 |
| Fulton 1989 | Grade 2 | Tested as Steareth-20 |
Our list's figure is within what these papers report.
Common questions
- Is steareth-2 comedogenic?
- Steareth-2 is rated 2 on the comedogenic scale, which is the low band.
- Is steareth-2 non comedogenic?
- Not exactly. Steareth-2 is rated 2, which is the low band rather than 0. Low and non-comedogenic are different things, and only a 0 means the second one.
- What is steareth-2's comedogenic rating?
- 2 out of 5 on our list. It is classed as Surfactant / Emulsifier / Alcohols & Derivatives.
Sources we checked this rating against
- Kligman AM, Kwong T. “An improved rabbit ear model for assessing comedogenic substances.” British Journal of Dermatology, June 1979;100(6):699–702. (opens in a new tab) The rabbit-ear assay behind published 0 to 5 comedogenicity grades.
- Fulton JE Jr. “Comedogenicity and irritancy of commonly used ingredients in skin care products.” Journal of the Society of Cosmetic Chemists, November/December 1989;40(6):321–333. (opens in a new tab) Rabbit ear. Each ingredient at 10 percent in propylene glycol unless stated, applied five days a week for two weeks, and graded 0 to 5 from the width of the follicles, measured by micrometer and under the microscope. The paper counts 0 to 1 as not significant, 2 to 3 as borderline and 4 to 5 as positive. Some grades depended on the supplier of the raw material, and some oils were also tested refined.
- Draelos ZD, DiNardo JC. “A re-evaluation of the comedogenicity concept.” Journal of the American Academy of Dermatology, March 2006;54(3):507–512. doi:10.1016/j.jaad.2005.11.1058 (opens in a new tab) Tested finished products on the backs of six people and concluded that “Finished products using comedogenic ingredients are not necessarily comedogenic.”