Comedogenic ingredients: what the 0–5 ratings really mean
Comedogenicity charts rate oils and esters from 0 to 5 and are widely shared online. Where these numbers come from, why they often disagree and why a single rating says little about a finished product.
Updated: 31 October 2026 · Reviewed by: Kamil Pyziak
What “comedogenic” means
A comedo is a clogged hair follicle – a blackhead or a whitehead. An ingredient is called comedogenic if it has been observed to promote the formation of comedones under certain test conditions. “Non-comedogenic” on a product is a claim that the finished product was formulated, and ideally tested, so as not to clog pores.
People with oily or blemish-prone skin often check ingredient lists against comedogenicity charts. That is understandable, but these charts are much less precise than their neat numbers suggest.
Where the 0–5 scales come from
Most charts circulating online go back to studies from the 1970s and 1980s that used the rabbit ear model: a raw material was applied repeatedly to the inner ear of a rabbit and the resulting follicle changes were graded, often on a scale from 0 (none) to 5 (severe). Some later work used tests on human skin, for example on the upper back.
The rabbit ear is known to be more reactive than human facial skin, so it may flag materials that cause no problems in real use. Many ingredients were tested undiluted or at concentrations far higher than in a cream, and the test said nothing about how the material behaves in a complete formula.
Why charts contradict each other
If you compare several charts, you will find the same ingredient rated 1 on one and 4 on another. Reasons include different test methods and concentrations, different raw material grades and suppliers, and the copying of numbers between lists without sources. Some values for whole groups of ingredients were also extrapolated rather than measured.
Names add to the confusion. “Coconut oil” on a chart may refer to Cocos Nucifera Oil, but derived ingredients such as Caprylic/Capric Triglyceride or Coco-Caprylate/Caprate, which are made from coconut or palm fatty acids, are different substances with different properties. A rating for one cannot simply be transferred to the others.
Ingredients often rated high – and why context matters
Ingredients that frequently appear with higher ratings include Isopropyl Myristate, Isopropyl Palmitate, Myristyl Myristate, Laureth-4, Cocos Nucifera Oil and cocoa butter (Theobroma Cacao Seed Butter). Ingredients often rated low include Squalane, Caprylic/Capric Triglyceride and, in many charts, Paraffinum Liquidum – although opinions on mineral oil differ between sources too.
In a finished product, concentration, the other ingredients, how the product is used (rinsed off or left on) and the individual skin all play a role. An ingredient with a high rating at a low level in a cleanser that is rinsed off is a very different situation from the same ingredient as the main component of a face oil.
Using the INCI list sensibly
If you have noticed that certain products repeatedly lead to blemishes, compare their INCI lists and look for shared ingredients, especially among the first ten or so, where most of the formula is. This personal pattern is usually more informative than any general chart.
A “non-comedogenic” claim must be truthful and supported by evidence under EU rules, but the label does not say how it was tested or for how long. Treat it as one piece of information, not a guarantee.
What the label does not tell you
An INCI list cannot predict whether a product will cause breakouts on your skin. It does not show concentrations, the raw material grade or the results of any tests, and comedogenicity scores were never designed to rate finished products.
Blemishes have many causes, including hormones, genetics, medication and skin conditions such as acne. If breakouts are frequent, painful or leave marks, talk to a pharmacist or a dermatologist rather than relying on ingredient charts.