Ingredient ratings / Glycine Soja (Soybean) Oil

Is soybean oil comedogenic? What the pore-clogging tests found

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

Label name

Glycine Soja (Soybean) Oil

Also listed as

soybean oil, soya oil, soy oil, soya bean oil, glycine soja oil

Comedogenic grade

3 / 5 · Borderline (2–3) or reported positive

Tests

• Fulton 1989: comedogenic 3/5, irritancy 0/5 — rabbit ear, 10% in propylene glycol

What the tests found

Soybean oil (INCI: Glycine soja oil) was graded only once, in James Fulton’s 1989 rabbit-ear survey [1]. Run at the survey’s standard 10% in propylene glycol (method), it scored 3 for pore clogging (follicular keratosis) and 0 for irritation.

On Fulton’s scale, a 3 is the top of the borderline band. In his words, 0-1 “is not considered significant,” 2-3 “is borderline,” and only 4-5 is consistently reproducible and “considered positive” [1].

Three details in the same table are specific to soybean:

• Source dependence: the oils section carries an asterisk meaning “results depend on source of raw material.” For sesame, avocado, mink, olive, almond and apricot kernel oils, Fulton printed a second, lower grade for a refined version. Sesame, for example, went from 3 to 1. No refined grade is given for soybean oil, so the paper does not show whether refining would lower it.
• Maleated soybean oil, a chemically modified soybean oil, graded 0 for both clogging and irritation [1].
• Hydrogenated vegetable oil, the shortening Crisco in Fulton’s test, graded 3. Fulton suspected it contained “residual irritating lipids.” The Cosmetic Ingredient Review (CIR) notes that the label name “hydrogenated vegetable oil” can cover a blend that includes soybean oil [3].

Where the evidence is weaker (or disagrees)

• No second lab. Soybean oil does not appear in Morris & Kwan’s 1983 study, so there is no second grade to compare.
• Fulton’s 3s for seed oils were not reproduced elsewhere. Fulton graded corn oil 3, the same as soybean. Morris & Kwan (Revlon, 1983) tested corn oil undiluted and graded it only 0-1 [2]. They also report that Kligman and Mills, in 1972, found most vegetable oils only weakly comedogenic, and that “all were inactivated when diluted to a 25% concentration in mineral oil.”
• Morris & Kwan saw a trend, not a rule. Oils high in both oleic and linoleic acid tended to react more, but they found “no consistent trend” by chain length [2].
• The 1996 reassessment. Kligman, revisiting the rabbit assay, wrote that vegetable oils “are usually non-comedogenic.” He argued that oiliness and comedogenicity are unrelated [4].
• Nothing on people. No comedone study of soybean oil on human skin turned up in our sources.

Where it shows up, and how much

CIR’s 2017 assessment of plant-derived fatty acid oils (Int J Toxicol 36 Suppl 3) draws on 2010 FDA registration data and 2010 industry surveys [3]. For soybean oil it reports:

• Number of uses: 912, of which 718 were leave-on.
• Maximum concentrations:
  • leave-on and rinse-off products: up to 95% each
  • nail and non-coloring hair products: up to 95%
  • products that touch the skin: up to 93%
  • bath products: up to 78%
  • lip products: 0.6-4%
  • eye-area products: 0.04-2%
• Related ingredients: hydrogenated soybean oil was used at up to 42% (39% in a lipstick tested in a repeat patch test), and soybean oil unsaponifiables at up to 0.2%.

CIR also notes that protein residues have been found in some soybean oil samples but not others. One study found protein in refined soybean oil with no detectable IgE binding [3]. That is an allergy question, separate from pore clogging.

If you want to avoid it

Soybean oil is often a bulk base oil, at up to 95% in the CIR survey [3], so the first thing to check is whether a product is mostly soybean oil or merely contains some. If you want a different base, these graded lower in Fulton’s survey [1]:

• Maleated soybean oil: 0, the same plant oil after chemical modification. It appears on labels under that name, not as plain soybean oil.
• Sunflower oil: 0, a seed oil that Fulton calls naturally less comedogenic
• Babassu oil: 1, irritation 0

Watch for hydrogenated vegetable oil (3) as well, since the CIR notes that name can cover a blend that includes soybean oil [1][3].

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. Methods p. 322, Table I p. 325, discussion pp. 327-328. 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. Table III and discussion p. 222. https://library.scconline.org/v034n05/1
3. Burnett CL, et al. Safety Assessment of Plant-Derived Fatty Acid Oils. Int J Toxicol. 2017;36(Suppl 3):51S-129S. doi:10.1177/1091581817740569. Table 5 and impurities section. Cosmetic Ingredient Review. https://cir-reports.cir-safety.org/view-attachment?id=ad62ac6b-8e74-ec11-8943-0022482f06a6
4. Kligman AM. Petrolatum is not comedogenic in rabbits or humans: a critical reappraisal of the rabbit ear assay and the concept of “acne cosmetica.” J Soc Cosmet Chem. 1996;47(1):41-48. https://library.scconline.org/v047n01/44

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.