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Ingredient ratings / Isopropyl Palmitate

Is isopropyl palmitate comedogenic? What the rabbit-ear tests found

By Skinredients · Checked against the sources 2026-10-16

Isopropyl palmitate graded 4/5 for pore-clogging in Fulton's 1989 rabbit-ear survey (10% in propylene glycol) and 3/5 undiluted in Morris & Kwan (1983). Two more rabbit studies (1984 and 2007) also called it positive, so the labs agree more here than for most ingredients. All of that evidence comes from the rabbit ear, which is more sensitive than human skin.

Label name
Isopropyl Palmitate
Comedogenic grade
3–4 / 5 · Positive in the test (4–5)
Tests

What the tests found

Isopropyl palmitate is the ester of palmitic acid (C16) and isopropyl alcohol. It is a close relative of isopropyl myristate, which is the rabbit-ear test’s reference positive. Few ingredients have results from as many separate studies.

  • Fulton (1989): 4/5 for pore-clogging, 1/5 for irritation. Fulton ran it at 10% in propylene glycol on three rabbits [1]. Only grades of 4-5 were reproducible enough for Fulton to call them positive, so this one counts. An irritation score of 1 means a few scales and no redness.
  • Morris & Kwan (1983): 3/5, undiluted. They tested one supplier’s material (Westwood Chemical) and scored it by microscopy only [2].
  • Fulton, Pay & Fulton (1984). Their abstract names it first among the “analogs” of isopropyl myristate that it calls ingredient offenders [3].
  • Nguyen, Dang & Maibach (2007). This independent group listed isopropyl palmitate first among 14 materials and reported it among the nine “deemed positive” [4]. The same study did not call cetyl alcohol, stearyl alcohol or petrolatum positive.

Fulton’s discussion and Table I place it on a chain-length scale [1]:

  • Larger fatty acids produce “less follicular reaction.” Palmitic acid (C16) graded 2/5 and myristic acid (C14) graded 3/5. The isopropyl esters follow the same order: isopropyl palmitate scored 4/5 and isopropyl myristate 5/5.
  • Esterifying a fatty acid with a small alcohol such as isopropanol makes “the combination … more potent than the fatty acid itself.”
  • Joining the same palmitic acid to a long alcohol (cetyl palmitate) gives 0/5. Fulton lists it among the large esters that “are not a problem.”

Where the evidence is weaker (or disagrees)

The four studies agree on direction but not on size. Fulton’s 10% solution scored higher than Morris and Kwan’s undiluted material, which is the opposite of what dose alone would predict. The labs scored differently: Fulton used micrometer readings by eye and under the microscope, while Morris and Kwan used microscopy only. Fulton also notes that his propylene glycol vehicle evaporates and “leaves a concentrate of the raw material” on the ear [1, 2]. The 1984 and 2007 results are known only from their abstracts, which do not give grades or test concentrations [3, 4].

Human evidence is thin. The Cosmetic Ingredient Review (CIR) summary describes undiluted isopropyl palmitate in 24-hour patches on 160 people [5]. There were five scores of 0.5/4 and no other reactions. It was also not a sensitizer when tested undiluted on 102 people. Those tests looked at irritation and allergy, not comedones.

The CIR report also describes isopropyl palmitate as a “lipid layer penetration enhancer” in topical formulations. It notes that a cream with 10% isopropyl palmitate was moderately irritating to guinea pig skin, while the same cream without it was not [5].

Like every grade here, these are rabbit results, which tend to run higher than human ones [6] (why). A flagged ingredient also doesn’t settle the question for a finished product: Draelos and DiNardo (2006) found such products could test clean on human skin [7].

Where it shows up, and how much

Isopropyl palmitate had 1,125 reported uses in the CIR’s final 2013 amended alkyl esters report: 995 in leave-on and 104 in rinse-off products [5]. Reported concentrations were:

  • 0.0001-60% in leave-ons and 0.0003-31% in rinse-offs
  • 0.1-34% in 81 eye-area products
  • 1-34% in 107 products that may be incidentally swallowed, such as lip products
  • 0.8-17% in aerosol sprays

Among the alkyl esters it ranked third by number of uses, after ethylhexyl palmitate and isopropyl myristate. The Panel concluded the group is safe as used “when formulated to be non-irritating” [5].

If you want to avoid it

Swapping to another isopropyl ester doesn’t help: in Fulton’s table, isopropyl myristate scored 5, isopropyl isostearate 5 and isopropyl linoleate 4 [1]. Among non-isopropyl esters, these scored low at the same 10% level [1]:

  • Cetyl palmitate: 0, irritation 0. It is the same palmitic acid on a C16 alcohol instead of isopropanol, the clearest case of the chain-length point above.
  • Octyldodecyl stearate: 0, irritation 0
  • Behenyl erucate: 0, irritation 0
  • Caprylic/capric triglyceride (printed as “glyceryl tricapylo/caprate”): 1, irritation 1

Because isopropyl palmitate is often used at double-digit percentages, its position near the top of a label may say more than its presence alone.

Sources

  1. Fulton JE Jr. Comedogenicity and irritancy of commonly used ingredients in skin care products. J Soc Cosmet Chem. 1989;40(6):321-333. https://library.scconline.org/v040n06/13
  2. Morris WE, Kwan SC. Use of the rabbit ear model in evaluating the comedogenic potential of cosmetic ingredients. J Soc Cosmet Chem. 1983;34(5):215-225. https://library.scconline.org/v034n05/1
  3. Fulton JE Jr, Pay SR, Fulton JE 3rd. Comedogenicity of current therapeutic products, cosmetics, and ingredients in the rabbit ear. J Am Acad Dermatol. 1984;10(1):96-105. https://pubmed.ncbi.nlm.nih.gov/6229554/
  4. Nguyen SH, Dang TP, Maibach HI. Comedogenicity in rabbit: some cosmetic ingredients/vehicles. Cutan Ocul Toxicol. 2007;26(4):287-292. https://pubmed.ncbi.nlm.nih.gov/18058303/
  5. Cosmetic Ingredient Review. Amended Safety Assessment of Alkyl Esters as Used in Cosmetics (Final Amended Report, April 12, 2013). https://www.cir-safety.org/sites/default/files/alkyle032013rep.pdf
  6. Mills OH Jr, Kligman AM. A human model for assessing comedogenic substances. Arch Dermatol. 1982;118(11):903-905. https://pubmed.ncbi.nlm.nih.gov/7138047/
  7. Draelos ZD, DiNardo JC. A re-evaluation of the comedogenicity concept. J Am Acad Dermatol. 2006;54(3):507-512. https://pubmed.ncbi.nlm.nih.gov/16488305/

Comedogenic grades describe single raw materials tested in a lab, usually on rabbit ears. They are a guide for acne-prone skin, not a prediction for any product or person, and this page is not medical advice. How the scale works.