Guide

Evidence reviewedNovember 13, 2026

Medical reviewDr. Abdurrahman Efem

Practical reviewMerve Akkaya

Comedogenic ratings explained: are they reliable?

Comedogenic ratings are a 0 to 5 score for how likely an ingredient is to clog pores, mostly based on rabbit-ear tests from the 1970s and 1980s. They are a rough warning sign at best: the same ingredient can behave differently depending on its concentration, grade and the rest of the formula, and a finished product is what reaches your skin.

0 to 5 scaleRabbit-ear originsFormula beats ingredient

Scale0 (none) to 5 (severe)

OriginRabbit-ear assay

Tested atOften 10% in a solvent

Better guideFinished-product testing

The short answer

Comedogenic ratings are only partly reliable. The familiar 0 to 5 scores come mainly from rabbit-ear studies, where ingredients were often tested at 10% in a solvent; rabbit ears react more strongly than human skin, and results change with the ingredient’s grade and the product it is in. A 2006 study in the Journal of the American Academy of Dermatology concluded that finished products containing comedogenic ingredients are not necessarily comedogenic. Use ratings as a rough flag for very high scorers, but judge products by the full formula, a non-comedogenic claim backed by testing, and how your own skin responds.

Key takeaways

The 0 to 5 scale grew out of rabbit-ear testing; 0 to 1 means not significant, 2 to 3 borderline, 4 to 5 likely pore-clogging.
Ratings depend on concentration, raw material grade and vehicle, so one ingredient can score very differently across studies.
Finished-product testing on human skin, plus your own patch test, tells you far more than an ingredient’s number.

The basics

What is a comedogenic rating?

“Comedogenic” means likely to cause comedones (clogged pores, such as blackheads and whiteheads). A comedogenic rating tries to put a number on that risk for a single ingredient. The best-known scale runs from 0 to 5 and was popularized by dermatologists Albert Kligman and James Fulton, who adapted the rabbit-ear assay for cosmetics in the 1970s.

In the rabbit-ear test, an ingredient is applied to the inner ear of a rabbit for a couple of weeks, and the follicles are then measured and examined under the microscope. In Fulton’s widely cited 1989 paper, most ingredients were mixed with propylene glycol at about 10%, applied five days a week for two weeks, and graded 0 to 5. He also graded irritation separately on its own 0 to 5 scale.

Score	What it meant in the test	How to read it today
0 to 1	No significant follicle change	Low concern for most people.
2 to 3	Borderline or moderate effect	Depends heavily on amount and formula; try it and watch.
4 to 5	Clear follicle plugging	Worth avoiding high up the ingredient list if you clog easily.

A “non-comedogenic” label is a related but different idea, covered in depth in what does non-comedogenic mean?. This page focuses on the ingredient numbers you see in online lists.

The catch

Why comedogenic ratings are not very reliable

Wrong skin

Rabbit ears overreact

A 2014 review in Skin Inc. notes rabbit ears are more sensitive than human skin and respond faster. Fulton himself wrote that not everything that irritates the model will irritate human skin.

Wrong dose

Tested at concentrations you rarely meet

Many ratings come from about 10% of the ingredient in a solvent. In real products an oil may be 1% or 30%, mixed with dozens of other ingredients.

Wrong grade

Source and refining change results

Fulton noted that jojoba and mineral oil scored differently depending on the raw material, and refined avocado oil did better than unrefined.

Wrong unit

Products, not ingredients, touch your skin

Draelos and DiNardo tested finished products on human backs and concluded products made with comedogenic ingredients are not necessarily comedogenic.

There is also no single official list. Different studies, and the websites that copy them, sometimes give the same ingredient different scores, and some modern ingredients were never tested at all. In the US, the FDA does not keep a list of ingredients banned from “non-comedogenic” products, according to the Skin Inc. review, so the claim relies on each brand’s own testing.

That does not make the numbers useless. Fulton observed that ingredients which did not clog pores in rabbits also tended not to in people; the uncertainty is mostly with high scorers. So treat a 4 or 5 as a flag to check, and a 0 or 1 as reassuring but not a guarantee.

Common questions

Is jojoba oil comedogenic? Is squalane? A quick reference

Ingredient	Rabbit-ear rating (Fulton 1989)	Practical note
Jojoba oil	0 to 2, depending on source	Generally low risk; quality and purity matter.
Squalane	Not verified in the original study	Widely regarded as low risk and stable; see should you use squalane?
Anhydrous lanolin	0 to 1	Low pore risk, but a known allergen for some people.
Acetylated lanolin alcohol	4	Fulton linked the high score to an additive, cetyl acetate.
Mineral oil	Variable by grade	Cosmetic-grade versions are usually well tolerated.
Cocoa butter	4	Often a problem on acne-prone faces.
Coconut butter	4	Fine on body skin for many; caution on the face.
Isopropyl palmitate	4	A common emollient worth noticing if you clog easily.
Isopropyl myristate	5 (used as the positive control)	The classic pore-clogger; check if it is high on the list.
Silicones (e.g., dimethicone)	Described as not a problem	Generally fine for acne-prone skin.

Jojoba and squalane are the two oils people ask about most, and they are compared directly in squalane vs jojoba oil. Some people also look at an oil’s fatty acid profile; oils richer in linoleic acid are often suggested for acne-prone skin, though the evidence is limited. If you are unsure whether you need an oil at all, read do you need face oil?

Practical guide

How to use comedogenic ratings sensibly

Start with your skin, not the list
If you rarely get clogged pores, ratings matter little. If you get blackheads, whiteheads or comedonal acne, they are worth a glance.
Look at position on the label
Ingredients are listed roughly from most to least. A high scorer near the end is usually present in small amounts; see how to read an ingredient list.
Prefer tested finished products
A non-comedogenic claim backed by human testing of the whole formula is more meaningful than any single ingredient score. The AAD recommends non-comedogenic products for acne-prone skin.
Introduce one product at a time
Use a new product for a few weeks before adding another, so you can tell what helps or hurts; see how to introduce a new skincare product.
Watch the right areas
New small bumps where you apply the product, within a few weeks, are the signal. Keep notes or photos.
Do not over-correct
Fearing every oil can push you toward harsh, drying routines, which bring their own problems. A simple moisturizer suits most acne-prone skin.

Not every bump is a clogged pore. Flat gray dots on the nose are usually normal sebaceous filaments, and itchy, uniform bumps may be fungal acne, which follows different rules. Persistent blockages are covered in clogged pores.

Safety and professional-help boundaries

When breakouts need more than an ingredient check.

If a product causes itching, burning, swelling or a rash, stop it; that is irritation or allergy, not comedogenicity, and may need a doctor if it persists.
Painful, deep or scarring breakouts need a dermatologist, not just a cleaner ingredient list.
Sudden widespread bumps after a new product or medicine should be checked by a clinician.
If you are pregnant or breastfeeding, check acne treatments as well as moisturizers; see skincare during pregnancy.
Patch testing helps with irritation and allergy; see how to patch test skincare, but it will not show slow pore-clogging, which takes weeks to appear.

Frequently asked questions

Short answers to common questions

What is a comedogenic rating?

It is a score, usually from 0 to 5, for how likely an ingredient is to clog pores. Most ratings come from rabbit-ear tests run decades ago, so they are only a rough guide.

Are comedogenic ratings reliable?

Only partly. Scores change with concentration, ingredient grade and the rest of the formula, and rabbit ears react more strongly than human skin.

Is jojoba oil comedogenic?

Jojoba oil is generally considered low risk. In Fulton’s 1989 rabbit-ear study it scored 0 to 2 depending on the raw material source.

Is squalane comedogenic?

Squalane is widely regarded as low risk for clogged pores and is usually well tolerated. As with any oil, watch for new bumps when you start using it.

Is coconut oil comedogenic?

Coconut-derived fats can clog pores in acne-prone people; coconut butter scored 4 in Fulton’s rabbit-ear testing. Many people tolerate it on the body but not on the face.

What does a comedogenic rating of 0 mean?

It means the ingredient did not cause significant pore plugging in testing. It is reassuring, but it does not guarantee a product containing it will suit you.

Can a product with a comedogenic ingredient still be non-comedogenic?

Yes. A 2006 study found that finished products made with comedogenic ingredients are not necessarily comedogenic, because dose and formula matter.

Are oleic acid-rich oils more comedogenic?

Some people with acne-prone skin find oils high in oleic acid heavier, while linoleic-rich oils feel lighter. Evidence is limited, so judge by your own skin’s response.

What is the most comedogenic ingredient?

Isopropyl myristate is the classic example; Fulton used it as the positive control with a score of 5. Cocoa butter, isopropyl palmitate and some lanolin derivatives also scored highly.

Should I avoid all oils if I have acne-prone skin?

No. Many oils and emollients are low risk, and over-drying your skin can backfire. Choose tested non-comedogenic products and introduce them one at a time.

Editorial Record

Editorial status: reviewed
Medical reviewer: Dr. Abdurrahman Efem
Practical reviewer: Merve Akkaya
Last reviewed: November 13, 2026

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Sources reviewed

Evidence behind this page

Sources support the general editorial guidance shown here. They do not replace personal medical advice from a qualified clinician.