Pore-Clogging Ingredients Checker: Your Comedogenic Guide
Your skincare label has 30 ingredients. You have about 45 seconds and zero lab equipment. A pore clogging ingredients checker gives you a starting point, but only if you understand what the ratings mean and what they don't.
This guide explains how the comedogenicity scale works, where it came from, why it's imperfect, and which common ingredients have shown up repeatedly as high-risk. The centerpiece is a reference table of 20+ ingredients with their ratings and category notes. Bookmark it, use it at the shelf, and share it with anyone who breaks out after switching moisturizers.
Key Takeaways
- Comedogenicity ratings come from a rabbit-ear test developed in the 1970s. The scale is useful as a first filter but imperfect: rabbit skin is far more reactive than human skin, and concentration and formulation matter.
- On the 0-5 scale used in that assay, 0-1 was treated as non-comedogenic and 3 or above as significantly comedogenic, per the 2025 JAAD Reviews summary of the literature.
- The term "non-comedogenic" on product packaging has no legal definition in the US. The FDA does not regulate the claim.
- Tallow does not appear on the most commonly cited high-comedogenic ingredient lists, but it was never formally rated in the primary comedogenicity studies either, so there is no published number for it in any direction. Acne-prone readers should patch-test.
- FATCO uses tallow as a base ingredient because it shares fatty acids with the skin's surface lipids, unlike several plant oils that carry high published rabbit-assay scores.
What "Comedogenic" Actually Means
Comedogenic means "capable of clogging pores." More precisely, a comedogenic ingredient promotes abnormal keratinization inside the follicular channel, leading to a plug of dead cells and sebum. When that plug is open to air, you get a blackhead. When the follicle is fully blocked, a whitehead forms. Eventually, inflammatory papules and pustules can follow.
Not every person's skin will react the same way to a comedogenic ingredient. Genetic factors, skin type, how often a product is applied, and how much of the ingredient is actually in the formula all influence whether a reaction happens. That context matters, and any honest checklist will say so.
The 0-5 Comedogenicity Scale: Where It Comes From
The scale traces back to 1972, when dermatologists Albert Kligman and Otto Mills coined the term "acne cosmetica" to describe breakouts caused or worsened by cosmetic products. To screen ingredients efficiently, researchers developed the rabbit ear assay. As the 2025 JAAD Reviews summary describes it, a test substance is applied to the inner pinna or external ear canal of albino rabbits once or several times weekly for two to four weeks, often under occlusion, and the tissue is then examined visually and histologically for comedone formation. Most studies graded results 0 to 5.
| Rating | What the grade meant in the assay |
|---|---|
| 0 | No follicular keratin plugging |
| 0-1 | Treated as non-comedogenic |
| 2 | Between the two thresholds, no formal label |
| 3 and above | Considered significantly comedogenic |
| 5 | Severe comedone formation |
The published thresholds are only the two ends and the 3-and-above cutoff. The in-between labels you see on consumer checkers ("very low risk", "moderate") are interpretation, not something the source studies assigned.
Fulton and colleagues published an ingredient screening list in the Journal of the American Academy of Dermatology in 1984 based on rabbit ear data, and in 1989 an American Academy of Dermatology expert panel endorsed the grading system, advising that ingredients scoring 0-1 could be treated as safe for acne-prone individuals. That 1984 list, and variations of it, is what most pore clogging ingredients checker tools still draw from today.
Why the Scale Is Imperfect (and Honest Sources Say So)
The rabbit ear model is extremely sensitive, so not everything that reacts in it reacts on human skin. When Kligman and Mills built a human model in 1982, they found that some substances that were potent comedogens in rabbits produced little or no comedone formation in people, and proposed that a substance would need to score consistently higher than 3 in the rabbit assay to indicate meaningful comedogenic risk in humans. That account comes from the 2025 clinical review of comedogenicity in JAAD Reviews, which also notes that the FDA has no legal definition for "non-comedogenic," so any brand can use the label without clinical testing.
Draelos and DiNardo reinforced the point in 2006. Their re-evaluation of the comedogenicity concept in the Journal of the American Academy of Dermatology tested finished cosmetic products in a human model and concluded that "finished products using comedogenic ingredients are not necessarily comedogenic."
What this means for reading a label: a single comedogenic ingredient in a product doesn't guarantee a breakout. Concentration matters. Formulation matters. Your specific skin type matters. The checker table below is your starting filter, not your final verdict.
How to Check a Label for Pore-Clogging Ingredients
Cosmetic ingredients in the US are declared under 21 CFR 701.3, which requires descending order of predominance. There is an important exception: brands may instead list everything above 1 percent in descending order and then everything at 1 percent or less in any order, with color additives allowed at the end. So position tells you a lot at the top of a list and much less at the bottom.
Here is a practical process:
- Pull up the ingredient list (or use a label-photo app to scan it).
- Run each ingredient against the checker table below.
- Flag anything rated 3 or higher, especially if it appears in the first half of the list.
- Note how many flagged ingredients appear. One low-concentration item at the bottom is different from three high-rated items in the top five.
- Patch test before committing to a full-face routine, particularly if you know your skin is acne-prone.
The Pore-Clogging Ingredients Checker Table
Two things to understand before you use this table. First, the numbers are not ours and are not facts about your skin: every rating below is reported as published, with the source named in its own column. Second, most of the ingredients people expect to find on a checker have no published rating at all. The 2025 JAAD Reviews authors are explicit that the consumer comedogenicity databases are "not governed by scientific or regulatory standards," so where the literature has no number, this table says so rather than inventing one. Rows where the number does exist are the ones where acne-prone skin has the strongest reason to patch-test.
| Ingredient | Category | Published rating (0-5) | Where the rating comes from | Notes for Acne-Prone Skin |
|---|---|---|---|---|
| Isopropyl myristate | Ester / emollient | 4-5 | JAAD Reviews 2025, Table I | The most-cited offender; used even in some tretinoin vehicles |
| Octyl palmitate | Ester / emollient | 4-5 | JAAD Reviews 2025, Table I | Early rabbit-assay data, limited human validation |
| Acetylated lanolin | Lanolin derivative | 4-5 | JAAD Reviews 2025, Table I | Comedogenic in the rabbit model; also noted in human occlusion studies. Common in dry-skin balms |
| Cocoa butter | Natural butter | 4-5 | JAAD Reviews 2025, Table I | Variable; some human reports of worsening acne |
| Coconut oil | Natural oil | 4-5 | JAAD Reviews 2025, Table I | Patchy evidence; may worsen acne in susceptible individuals |
| Wheat germ oil | Natural oil | 4-5 | JAAD Reviews 2025, Table I | Consistently comedogenic in the rabbit assay, minimal human validation |
| Sodium lauryl sulfate | Surfactant | 3-4 | JAAD Reviews 2025, Table I | Noted for irritation as well as potential comedogenicity |
| Tocopherol (vitamin E) | Antioxidant | 2-3 | JAAD Reviews 2025, Table I | Listed as comedogenic in some reports, variable in humans |
| Myristyl myristate | Ester / emollient | no published number located | Named, without a score, in Fulton 1984 among the isopropyl myristate analogs | Same structural family as isopropyl myristate |
| Ethylhexyl palmitate | Ester / emollient | no published number located | Named, without a score, in JAAD Reviews 2025 as a comedogenic ingredient found in products marketed as non-comedogenic | Often in "lightweight" formulas |
| Lanolin alcohol | Lanolin derivative | no published number located | Fulton 1984 flags lanolin derivatives generally, especially acetylated and ethoxylated | Watch lip balm and hand cream labels |
| Algae / seaweed extract | Marine extract | no published number located | Circulates in consumer checkers only | Individual response may vary |
| Linseed oil (flaxseed) | Natural oil | no published number located | Circulates in consumer checkers only | High polyunsaturated fats, prone to oxidation |
| Tallow (beef fat) | Animal fat | not formally rated | Absent from both the 1984 rabbit-assay list and the 2025 JAAD Reviews table | Never assayed, so there is no number in either direction. Shares fatty acids with the skin's surface lipids. Patch-test for acne-prone skin |
| Silicone (dimethicone) | Silicone | no published number located | Circulates in consumer checkers only | May trap other ingredients against the skin surface |
| Sweet almond oil | Natural oil | no published number located | Circulates in consumer checkers only | Generally well tolerated |
| Shea butter | Natural butter | no published number located | Circulates in consumer checkers only | Individual response varies |
| Jojoba oil | Liquid wax ester | no published number located | Circulates in consumer checkers only | Technically a wax ester rather than an oil |
| Rosehip seed oil | Natural oil | no published number located | Circulates in consumer checkers only | High linoleic acid, often suggested for acne-prone skin |
| Squalane | Hydrocarbon | no published number located | Circulates in consumer checkers only | The hydrogenated form of squalene, a lipid the skin already produces |
| Argan oil | Natural oil | no published number located | Circulates in consumer checkers only | Balanced fatty acid profile |
| Glycerin | Humectant | never assayed | Water-soluble humectants were not part of the lipid-focused rabbit screens | Draws moisture to skin; not a plausible follicular plug |
| Hyaluronic acid | Humectant | never assayed | Water-soluble humectants were not part of the lipid-focused rabbit screens | No mechanism for follicular plugging at standard concentrations |
| Niacinamide | Vitamin B3 | never assayed | Water-soluble actives were not part of the lipid-focused rabbit screens | Well tolerated in general use |
A note on concentration and formulation: an ingredient appearing at the bottom of a 30-ingredient list at trace levels behaves differently than the same ingredient at position 3, and a finished formula behaves differently again from the isolated raw material the assay tested. Use this table as a first screen, not an absolute blacklist.
Where Does Tallow Fit? An Honest Answer
The honest answer is that tallow (rendered beef fat) was never tested. It does not appear on the commonly cited high-comedogenic lists, but it is also absent from Fulton's 1984 rabbit-assay list and from the 2025 JAAD Reviews table, so there is no published number for it in either direction. Anyone who quotes you a comedogenic rating for tallow is quoting a consumer database, not a study.
What can be stated is composition. USDA FoodData Central lists beef tallow at about 36 g oleic acid, 25 g palmitic acid and 19 g stearic acid per 100 g of fat, which works out to roughly 38, 26 and 20 percent of its total fatty acids. Those three are among the fatty acids present in the skin's own surface lipids, which is the basis of FATCO's formulation approach: use fats that share components with what the skin already makes. That is a compositional overlap, not an equivalence. Human sebum's single most abundant fatty acid is sapienic acid, which the dermatology literature notes has not been identified in the sebum of any other animal, so no animal fat is a stand-in for sebum.
There is an honest caveat worth knowing. Sebum from acne-prone skin has been repeatedly found to contain decreased amounts of linoleic acid, and tallow is a low-linoleic fat (roughly 3 g per 100 g by the same USDA data). The research on tallow and acne-prone skin specifically is limited, and individual variation is real.
FATCO's position: there is no evidence that tallow is comedogenic, and no published rating claiming that it is. That is not the same as proof that it is safe for every acne-prone reader, so patch-test first, just as you would with any new product. Start on a small area, wait two to three weeks, and watch how your skin responds. To understand the oily skin angle before adding any new face product, FATCO's oily skin and tallow guide covers the full picture.
Got Questions?
Comedogenic Ingredients FAQ
Q Is coconut oil pore clogging?
The 2025 JAAD Reviews table reports coconut oil at 4-5 in the rabbit ear assay, among the highest natural oils listed. The same table calls the human evidence patchy, noting it may worsen acne in susceptible individuals rather than everyone. It's a frequent ingredient in "natural" moisturizers and lip products, so a label check is worthwhile.
Q Is tallow comedogenic?
There is no published rating, because tallow was never included in the rabbit-assay screens or the modern review tables. It shares fatty acids with the skin's surface lipids, which is the basis of its long use in ancestral skincare, but shared composition is not a test result. Acne-prone users should patch-test.
Q What does a comedogenic rating of 0-2 mean?
In the source literature only the ends are defined: 0 meant no follicular plugging, and 0-1 was the range a 1989 AAD expert panel endorsed as safe for acne-prone skin. A 2 sits below the 3-and-above cutoff for significant comedogenicity but carries no formal label. Save your attention for ingredients rated 3 or higher.
Q Can a product be "non-comedogenic" and still break me out?
Yes, because the term carries no legal definition, so brands can use it without independent testing. A finished formula can also behave differently than an isolated ingredient, especially at trace concentrations. Reading the actual ingredient list and patch-testing beats trusting the label alone.
Q Does the order of ingredients on a label matter for pore clogging?
Mostly yes. US rules require descending order of predominance, so a flagged ingredient listed second matters far more than the same one listed twenty-seventh. The caveat is that brands may list everything at 1 percent or less in any order, and color additives last, so the bottom of a long list tells you less than the top does.
Q What clean personal care ingredients are safe for acne-prone skin?
None of the usual suspects carry a published high rating: glycerin, hyaluronic acid and niacinamide were never in the rabbit-assay screens at all, and squalane, rosehip seed oil and jojoba appear in consumer checkers without a study behind the number. For a fat-based option, tallow was likewise never assayed, so nothing flags it. Start there if you're curious whether tallow suits your skin type.
The FATCO Alternative
Most moisturizers trying to dodge the "pore-clogging" label are built on synthetic esters and silicones, and several of those esters are the highest-rated entries in the table above. FATCO takes a different approach: grass-fed tallow, which shares fatty acids with the skin's surface lipids, in a short ingredient list you can read in one pass. Patch-test and see how your skin responds.
