Sodium Lauryl Sulfate (SLS)
Sodium lauryl sulfate, which our list names Sodium Lauryl Sulfate (SLS), is rated 5 on our list, in the high band, and the number is traced: Morris and Kwan 1983 graded it 0 and Morris and Kwan 1983 graded it 0.
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 sodium lauryl sulfate comedogenic?
Sodium Lauryl Sulfate is rated 5 on the comedogenic scale, which is the high band. The rabbit-ear studies we have read give it less: Morris and Kwan 1983 gave it 0 (10% aqueous); Morris and Kwan 1983 gave it 0 (5% aqueous). Our list's 5 is above all of them.
A foaming cleanser and one of the best documented skin irritants: it is the standard substance used to cause irritation in skin studies. Rabbit-ear tests have not shown it to clog pores.
- Comedogenic rating
- 5 out of 5
- Band
- High: Clear plugging in the rabbit-ear test. The first band to check in a leave-on product.
- Where the number comes from
- Traced to Morris and Kwan 1983. The section on who rated it prints each grade.
- Composition
- Surfactant / Cleanser / Detergents
- Also written as
- No common variants recorded
What a 5 means in practice
A 4 or 5 is the top of the scale. In the rabbit-ear test, Fulton 1989 counted 4 to 5 as a clear positive: the ingredient plugged the follicles, and did so repeatably. A person's skin reacts less readily than a rabbit's ear, and a product holds far less of the ingredient than the test did, so treat this band as the first thing to check in anything that stays on your skin. It does not prove the ingredient will cause a breakout. A rinse-off product is on the skin for seconds.
Two things change what this number is worth. Ingredients are listed in descending order of concentration, so sodium lauryl sulfate near the top of a label matters far more than sodium lauryl sulfate 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 is two bands above the research. Our list gives sodium lauryl sulfate 5. Morris and Kwan 1983 gave it 0 (10% aqueous); Morris and Kwan 1983 gave it 0 (5% aqueous). We report the list as it stands and show the papers beside it. Where the list and the research disagree.
Our list gives sodium lauryl sulfate 5. 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 |
|---|---|---|
| Morris and Kwan 1983 | Grade 0 | Tested as Sodium Lauryl Sulfate (10% aqueous) |
| Morris and Kwan 1983 | Grade 0 | Tested as Sodium Lauryl Sulfate (5% aqueous) |
Fulton 1976 names sodium lauryl sulfate among the emulsifiers it found comedogenic, without a grade in the abstract.
Nguyen and colleagues 2007 tested it and did not list it among the materials deemed positive.
Ahn and colleagues 1985 reports moderate comedogenicity in the rabbit ear canal, in an abstract that gives no 0 to 5 grade.
Our list's top figure, 5, is higher than anything in these papers.
Others in the same family
Where sodium lauryl sulfate comes up on this site
Common questions
- Is sodium lauryl sulfate comedogenic?
- Sodium Lauryl Sulfate is rated 5 on the comedogenic scale, which is the high band. The rabbit-ear studies we have read give it less: Morris and Kwan 1983 gave it 0 (10% aqueous); Morris and Kwan 1983 gave it 0 (5% aqueous). Our list's 5 is above all of them.
- Is sodium lauryl sulfate non comedogenic?
- No. Sodium Lauryl Sulfate is rated 5 on the comedogenic scale, which is the high band. That is the number on our list; the papers we read grade it lower (see Who rated it).
- What is sodium lauryl sulfate's comedogenic rating?
- 5 out of 5 on our list. It is classed as Surfactant / Cleanser / Detergents. The rabbit-ear studies we have read give it less: Morris and Kwan 1983 gave it 0 (10% aqueous); Morris and Kwan 1983 gave it 0 (5% aqueous). Our list's 5 is above all of them.
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.
- Morris WE, Kwan SC. “Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients.” Journal of the Society of Cosmetic Chemists, August 1983;34(5):215–225. (opens in a new tab) Rabbit ear canal, at the Revlon Research Center. Each material applied undiluted unless stated, once a day five days a week for 14 applications, and graded 0 to 5 by microscope only. The authors set out to recheck earlier results because investigators disagreed.
- Fulton JE Jr, Bradley S, Aqundez A, Black T. “Non-comedogenic cosmetics.” Cutis, February 1976;17(2):344–351. (opens in a new tab) Rabbit ear. Read at abstract level: it names butyl stearate, isopropyl myristate and sodium lauryl sulfate among the emulsifiers found comedogenic.
- Nguyen SH, Dang TP, Maibach HI. “Comedogenicity in rabbit: some cosmetic ingredients/vehicles.” Cutaneous and Ocular Toxicology, 2007;26(4):287–292. (opens in a new tab) Rabbit ear. Read at abstract level: of fourteen materials, the first nine named (isopropyl palmitate, isopropyl myristate, butyl stearate, isopropyl isostearate, decyl oleate, isostearyl neopentanoate, isocetyl stearate, myristyl myristate and cocoa butter) were deemed positive; cetyl alcohol, paraffin, stearyl alcohol, sodium lauryl sulfate and petrolatum were not among them.
- Ahn HY, Myung KB, Hahm JH, Kook HI. “An experimental study on comedogenicity of several external contactants.” Korean Journal of Dermatology, October 1985;23(5):620–629. (opens in a new tab) Rabbit ear canal; in the abstract’s words, the materials were applied to one ear canal of rabbits "for 6 weekdays for 2 weeks". Read at abstract level: the full text is not online. The abstract sorts ingredients into none, mild, moderate and severe with no 0 to 5 grade, and lists propylene glycol under both none and moderate. Kligman 1996 says that putting test materials inside the ear canal gave false positives in his own 1972 study, because loose horny material collects in the follicles there.
- Lee CH, Maibach HI. “The sodium lauryl sulfate model: an overview.” Contact Dermatitis, July 1995;33(1):1–7. (opens in a new tab) Sodium lauryl sulfate is the most widely used substance for causing acute and cumulative irritation in skin studies. The review sets out decades of that work.
- 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.”