How Reliable Is The Comedogenic Rating For Skincare Products?

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With so many products available in the market these days, it’s difficult to know which one will work for your skin type.

You are someone who likes to do ample research before buying any product. You avidly go through each of the ingredients listed on the product carefully to understand what each ingredient does to your oily skin.

Each ingredient has a different effect on oily skin. If you are not a skin expert, you would not know which ingredient will cause your pores to get jammed, and which will help unclog them.

Since no ingredient is totally great or completely worthless, you would want to know which ingredient is relatively good or relatively bad when it comes to addressing your problem of clogged pores.

In order to address this issue, there exists an industry-wide scale called the “comedogenic scale”.

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What Is The Comedogenic Scale?

Comedogenic Scale ranks the ingredients on the basis of its ability to clog your pores.

Each substance is given a rating between 0 and 5.

Any substance with a rating of 5 would be highly comedogenic (that is, would cause clogged pores willy-nilly), and a substance with a rating of 0 would be least comedogenic (or you could say, non-comedogenic).

comedogenic rating

If you have oily skin, you would know that acne and breakouts have their genesis in clogged pores. So, if you have oily and/or acne-prone skin, comedogenicity scale of an ingredient is something that you should be aware of.

What you are supposed to do is check the ingredients in your product against the ratings on the comedogenic list. If your product has a large number of comedogenic ingredients, it can lead to clogged pores and acne, if not, it’s less likely to clog your pores.

The problem here is, I don’t trust this scale too much. Why? Keep reading.

In this article, I will be discussing comedogenic ratings, why some products that have non-comedogenic ratings have comedogenic ingredients in their list, and why the scale cannot be trusted blindly. Also, I will help you figure out how you should choose the right product for your skin that will not break you out.

How about a little formal introduction to comedogenicity to kick this off?

What Is Comedogenicity?

The term “comedogenic” comes from the word “comedone”, which is a clogged hair follicle (also known as a pore) inside the skin.

Comedogenicity or comedogenic rating of an ingredient refers to the tendency of that ingredient to clog your pores. Clogged pores, in turn, can result in acne and breakouts.

A comedogenic scale ranks the ingredients on a scale of 0-5, 0 meaning the ingredient is completely non-comedogenic, and 5 meaning a product is highly comedogenic.

These are what the numbers in the comedogenic scale mean –

0 – Will Not Clog Pores

1 – Low probability to clog pores

2 – Moderately low probability to clog pores

3 – Moderate probability to clog pores

4 – Fairly high probability to clog pores

5 – High probability it will clog pores lists down common skincare ingredients and their comedogenic ratings, if you are interested.

What Are Comedogenic Ingredients In Skin Care Products?

comedogenic ingredients

Rabbit ear test was the first standard for testing the comedogenicity of common skincare ingredients.

Most of the ingredients that are considered comedogenic are based on these first comedogenicity tests performed in the 1980s by James Fulton, an American dermatologist, on rabbit ears. The ingredients were given a rating between 0-5, 0 being non-comedogenic ingredients, and 5 being extremely comedogenic ingredients.

Later, it was found that the model was flawed, and later models for testing comedogenicity of ingredients were also found to yield incorrect results.

Is proper testing even possible? Continue reading to find out.

How Do You Know If A Product Is Comedogenic Or Non-Comedogenic?

Well, the truth is – we don’t know for sure. As stated above, there is no proper research to conclude that a product is comedogenic.

All we know for sure is that there are certain products that have been confirmed to clog pores by enough people using the products containing them. These products have a high risk of being “comedogenic”.

There is no such list of ingredients that a product must contain in order to be classified as non-comedogenic. While the FDA defines a comedogenic ingredient as something that will clog pores, it does not define the list of ingredients a product must contain to be considered “non-comedogenic”.

This means that any company can claim that their product is non-comedogenic, without any guarantee that it will not clog your pores.

Where Do Numbers On The Comedogenic Scale Come From?

The numbers on the comedogenic scale come from studies that are performed by scientific researches, that are published in public journals. The notable among these is American Academy of Dermatology.

So that means the comedogenicity scale is quite reliable, right?

Well, a lot of claims in the skincare industry are backed by “scientific research”, but you don’t know the real story until you dig a bit deeper.

So, What’s Wrong With This Scale?

The problem is that this scale does not accurately reflect what happens when we include these ingredients in our skincare products. Let’s see why –

1.  Tests Are Not Performed In Real-World Conditions

Ideally, the tests for each ingredient should be performed on each individual, and then a comprehensive list should be prepared to state what ingredients clog pores and cause acne on a particular skin type.

But in the real world, that’s, of course, not practicable.

So, instead, the tests are performed in “mock” conditions, i.e. a condition that mimics the real-world situation and is much simpler to carry out and understand. Some examples of these tests are ‘Rabbit Ear Model’, ‘Human Model’ etc.

What does that mean? We can’t rely on these results as they are not performed in real-world conditions and are bound to be inaccurate.

2.  The Rabbit Ear Model For Testing Is A Flawed Model

The “Rabbit Ear Model“, which has long served as a model for determining the comedogenicity of ingredients, is flawed. Moreover, the method is cruel to the hapless animal.

In the Rabbit Ear Model for determining the comedogenicity of an ingredient, the ingredient was applied on the external part of a rabbit’s ears for about two weeks. After two weeks, the comedogenic behavior of the ingredient was determined based on whether or not any clogged pores were found on the surface of the rabbit’s ear.

Unfortunately, this resulted in a lot of false positives.

A lot of ingredients that are non-comedogenic on human skin are comedogenic on the rabbit’s ears, as rabbit’s ears are much more sensitive than human skin. Also, the rabbits have naturally enlarged pores. Some of the earlier results counted these large pores as acne, which resulted in more false positives.

rabbit model for comedogenic ratings

So basically, for a long time, there were ingredients people thought were comedogenic but which are actually not. A lot of these errors were corrected in the coming years.

One such example is petroleum jelly, which was earlier termed as comedogenic. This was corrected later on.

3.  The Human Model For Assessing Comedogenic Substances Is Also Flawed

After realizing the problems with the Rabbit Ear Model, tests were performed on human skin as well. However, it resulted in more problems.

Firstly, in the human model, the test substances were applied under seclusion for one month to the upper part of the backs of young adult, black men who have large follicles.

You get the problem here right?

Our face skin is different from our back skin. Our face is exposed to a lot more sunlight, dirt, dust and has a lot more hair follicles than our back. So, whether your face and your back will react the same to those ingredients is uncertain.

Also, since the tests were performed on people having large pores, it’s highly uncertain that people with smaller pores will have a similar response to those ingredients.

human model for comedogenic ratings

One other major problem with this test was that the area of application was covered with a bandage. Covering the area with bandage would result in more penetration, which means the substance is more likely to cause acne.

These tests are also normally performed on small sample sizes, so we are likely to get different results if the test is performed on another 100 people or another 1000 people.

4.  Comedogenic Ingredients Don’t Make A Comedogenic Product

If an ingredient is comedogenic on its own, it does not mean that a product having that ingredient will be comedogenic as well. How much quantity of the ingredient, in what concentration, is present in the product also matters.

If a product has an average comedogenic ingredient in large quantities, along with some other comedogenic ingredients, that’s when the product becomes harmful for your skin.

The same ingredient, when present in a more diluted form as the only comedogenic ingredient in the formulation, is less likely to cause any problems for most skin types.

5.  Everyone’s Skin Is Different

One major issue with accepting the comedogenic rating is the fact that everyone’s skin is different. Everyone has unique skin chemistry, different skin bacteria, and different activity levels. We all live under different environmental conditions and have different genes.

The same ingredient will not have the same comedogenicity potential for every person. All we can say is that people with oily skin are more prone to having acne, and if those people have sensitive skin as well, they are much more likely to develop acne.

So Again, Is the Comedogenic Scale Really Useful?

Everyone likes to take the easy way out. That is the reason why this scale has become such a popular way to determine whether a product is safe for acnegenic skin or not.

Just look at the ingredients on the product and if their comedogenic ratings are below 1, you are good to go. Or what’s even less hassle is to check the product for a mention of the word “non-comedogenic” to consider it good for oily and acne prone skin.

But we all know that the easiest way is not always the best way. Comedogenicity is a complex and an inadequately researched problem.

When is comedogenic scale useful?

If you are breaking out even after following a proper diet and exercise routine, it’s usually good to check the comedogenic scale for high rated ingredients in order to narrow down on what ingredients might be causing your acne.

If your skin is acne-prone and the product you want to buy has a large number of comedogenic ingredients, that too listed near the top, it’s a good idea to avoid that product or patch test it very carefully before using it.

Ingredients listed at the top are present in the highest concentrations in that product. However, if you see a highly comedogenic ingredient, but listed in the bottom rungs of the ingredient list, do not let it bother you much.

These ingredients are present only in diluted form, and sometimes it is necessary for the expert to include them in order for the whole formulation to be effective. lists a helpful table of ingredients that one must avoid while buying a product, and a table that one should consider avoiding while buying a product for acne-prone skin. You could perhaps keep a screenshot of this table handy for next time when you go out to buy a product.

Some ingredients like oils and butter are usually used in undiluted forms. The comedogenic scale can help you navigate these ingredients, if your skin is prone to acne and breakouts.

Perform Your Own Tests Instead

The best way to test skincare products is to use them on your own skin. A patch test is a very reliable way to check how your skin reacts to a product, before you start slathering it all over your face. If the product seems to be irritating your skin, no need to continue.

My advice for you is to stick to natural ingredients as far as possible, and avoid products filled with a lot of chemicals. This is why, I am always gung-ho about trying out DIY techniques at home to address my skincare needs.

If you have to buy readymade products, go for products made by companies that claim to use “safe” ingredients in their products and are trusted by people with skin type similar to yours. You can even go one step further and check their product pages for exact ingredients and the source of those ingredients.

Knowledge is power. A lot of websites have a great detail about various skincare ingredients. If you have sensitive skin, it’s worth spending the time understanding what ingredients are used in a product.

If a product is working for you and you find out that it has comedogenic ingredients, don’t just stop using it. It just means that the ingredients are not harming your skin.


So, this is all I had to share about the comedogenic rating. The only person who can make a decision about your skin is you! The amount of research you put into finding the best skincare products for your skin type is up to you. No one knows your skin better than you, not even the wise scientists who designed the comedogenicity scale.

I hope this article helped you understand a little about comedogenicity and you will now be able to make informed decisions about your skin.

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2 thoughts on “How Reliable Is The Comedogenic Rating For Skincare Products?”

  1. Thank you for the detailed breakdown! Even though there are some flaws with the comedogenic rating model, it’s still a great place to start before trying new skincare ingredients.


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