What Is "Non-Comedogenic" & Why Is It Important in Skincare?

Every day we see more and more brands using the label “non-comedogenic” on their products, beauty bloggers and estheticians use the term all too frequently to describe ingredients and give advice. But, what does this really mean, and more importantly, how reliable is it? 

The comedogenicity of ingredients is a topic really close to heart for long-time acne-sufferers. It’s because of problems like breaking out after using skincare and makeup products, that today we have scientists doing research and figuring out how to help us give meaning to the vast majority of ingredients in the skincare world. 

A comedogenic index scale has been developed and extensively shared and re-shared over the internet. It became a sort of a benchmark for people to determine if a product is right for them. 

Unfortunately, the matter is much, much more complicated than this, and even with a scale, we still can’t swear by or swear off skincare products or even ingredients. This doesn’t mean comedogenicity is not important.

Not to confuse you any further, let’s start with the basics and try to give you a full overview of the role of the “non-comedogenic” label in skincare. 

Defining Comedogenicity

The Basics - What Is a Comedo?

On its surface, our skin has tiny holes, or small openings of hair follicles that release oil and sweat. On certain areas of the skin where the pores are more densely distributed you can see them as tiny little dots. They play a vital role in the optimal functioning of the skin, which is why it’s important that they stay open. 

“Comedo”, or “comedones” in the plural form, is the fancy term that’s used to describe a blocked pore, which can’t function properly. 

Comedones are the mildest form of acne that develops when a pore is clogged. We can divide comedones into three categories: 

• Blackheads are clogged pores that are opened and you can see the plug on the surface of the skin. 
• Whiteheads are clogged pores that are closed and the plug is trapped below the surface of the skin. 
• Comedogenic acne is a term that refers to inflamed pimples and breakouts resulting from a complication of clogged pores and plug buildup. 

But what really clogs the pores? 

• Dead skin cells can clog the pores. For example, if you’re not washing and cleansing your face regularly, the dead skin cells on the surface might end up blocking the pores instead of being washed off. 
• Excess oil can clog the pores. Another major contributor to clogged pores is the excess sebum your sebaceous glands are producing. This is the fundamental problem for people with oily skin and one major reason that makes oily skin prone to acne. 
• Dirt and other pollutants from the external environment can clog the pores. It’s important to keep your hands, hair, and mobile phone away from your face since it’s the easiest way to bring dirt and bacteria, clog the pores, and cause infection.
• Skincare and makeup products can clog the pores. Anything that touches the skin’s surface has the potential to influence the functioning of the skin’s pores, which is also true for the products we’re using. It’s kind of ironic because the reason why we’re using skincare products and makeup is to reduce and conceal blocked pores.  

Now with that out of the way, let’s move on to “non-comedogenic” products and their popularity in the skincare world today.

What Is A “Non-comedogenic” Product?

“Non-comedogenic” is a fancy label that simply refers to the fact that the product is not likely to cause comedones (or pore blockages). This likelihood is determined by the concentration and combination of ingredients used in the product. 

When companies say that their product is non-comedogenic, they simply mean their product doesn’t contain any ingredients known to be comedogenic.

But, does this mean it will protect against acne and prevent breakouts?

No. It simply means that we’re ALMOST SURE it won’t contribute to more acne. Pretty disappointing right? But, it’s absolutely of vital importance, especially if you’ve been having trouble finding a product that won’t make you flare-up.

Today, a new term is emerging: “Non-Acnegenic” Products.

Acne is a condition that can be triggered by many factors, and not clogging the pores is simply not enough to indicate that the product is safe for acne-prone skin. Comedogenicity is the most important factor, but non-acnegenic products are also free from oils, fragrances, or harsh ingredients that irritate your skin. Anything that can make the product more suitable for acne-prone skin. Having in mind that this “comedogenicity” thing is extremely hard to be determined for simple ingredients, let alone complicated product formulations this topic is really complex

So, how is it done? How do we know that an ingredient is non-comedogenic, or the product is not likely to clog pores? 

When it comes to ingredients, we can turn to scientific research and findings that examine the composition of the ingredient. When it comes to products, we can rely on the comedogenicity tests the companies are conducting, like the Rabbit Ear Test and the Human Skin Test, both of which we’ll cover in the paragraph below. 

Let’s see what we know so far.

Comedogenicity And Fatty Acids

Simply put, fatty acids are the building blocks of the fat in our bodies and in the food we eat. The body breaks down fat from food to fatty acids, so it’s able to absorb it in the blood. I know, we’re used to being alarmed by the word fat when we hear it, but the truth is our body needs fat for energy and cell growth. 

Essential fatty acids are the fundamental building blocks of healthy cell membranes in your skin. You can obtain fatty acids internally or topically to help the skin produce the natural oil barrier, important for keeping the skin hydrated, plumper, and younger-looking.

Everything looks good, so where’s the problem? 

The problem is that fatty acids are making up the oil or sebum (which is also really important) on our skin. 

Sebum is an oily substance that makes up the natural oils on the skin, and that protects and keeps the skin hydrated. Sebum is made up of triglycerides (fatty acid chains), free fatty acids, wax esters, squalene, cholesterol esters, and cholesterol. 

Studies over the years have investigated the comedogenic activity of sebum, the skin’s natural oil, and free fatty acids. In 1974, a study published in the Archives Of Dermatology examined the relationship between acne vulgaris and free fatty acids. Results have shown that free fatty acids are comedogenic when applied in massive amounts to the skin’s surface. 

However, authors note that there’s also evidence showing reduced fatty acid levels in acne conditions. This implies that not all fatty acids have the same effect on the skin. The contradictory results still give scientists headaches and make the relationship between sebum, fatty acids, oil and other moisturizing ingredients even more complex. 

However, to keep things simple, we can sum up that today we know certain fatty acids can be irritating and cause comedogenic reactions, in certain amounts and for certain skin types. Groundbreaking, huh?

Some studies have shown that acne patients have a deficit in linoleic acid. This has lead to the development of many theories that argue that ingredients high in linoleic acid and low in oleic acid are more beneficial and less comedogenic than ingredients high in oleic and low in linoleic acids.

The Comedogenicity Of Oils And Butters

While we’re on the subject of the ratio of certain fatty acids, we have to talk about the comedogenic potential of oils, which are the essential ingredients in moisturizing products.

Most oils are composed of molecules known as triglycerides, which are esters composed of three fatty acid units linked to glycerol. Depending on the concentration and composition of triglycerides, the oils have different properties and comedogenic potential. 

The Comedogenic Rating of Oils

Many studies over the years, like the one from 1984 published in The Journal of the American Academy of Dermatology, have made an attempt to rate the comedogenicity of the most frequently used skincare products, oils, and other ingredients. 

Since then, The American Journal of American Academy of Dermatology has published a list of ratings for various oils and waxes. The so-called comedogenic index scale has been shared extensively over the internet. 

The Comedogenic Index Scale

0 – Not likely to clog pores

1 – Low risk of clogging pores

2 – Moderately low (may clog pores for some but be fine for most)

3 – Moderate risk of clogging pores (most depended on the skin type)

4 – Fairly high risk of clogging pores (fine for some, but clogging the pores for most people)

5 – High risk of clogging pores 

Source: The American Journal of American Academy of Dermatology database and case reports.

Does The Comedogenic Scale Really Work?

Well, it really depends on what are your expectations. The scale is developed using knowledge from scientific research and testing on animals and human subjects. This means that the values truly represent the chances of an ingredient to clog the pores in the general population.

But, how exactly is the ingredient going to work on your skin? No one can give you any guarantees. After all, clogged pores are not the only factor that contributes to the development of acne.

The scale is designed to give you a better understanding of how one ingredient is expected to work. If you consider the scale as a flexible guide on what to avoid, what to try next, or why your skincare products are not working, you’ll probably find it helpful.

But, if you expect to learn what ingredient or product will give you the best results, then you might end up disappointed. 

Scientists are working hard on developing better ways to predict the bioactivity of ingredients. Who knows, maybe in the near future we’ll have better measurements and ways to find the most fitting formula for our skin ailments.

Comedogenic Ingredients Vs. Comedogenic Products

Okay, up until now we were talking about non-comedogenic ingredients. But, what about the whole product? 

How do we know which skincare products are non-comedogenic? Is it a matter of simple multiplication of the comedogenic ratings of the ingredients in the formula? 

No, nothing is that simple. When products get labeled as non-comedogenic sometimes that means that the manufacturer didn’t use any ingredients known to be comedogenic in the formula. But, usually that means that the product was tested on rabbit's ears, or on human skin, and the results showed it’s unlikely to cause comedones. 

The Comedogenicity Of Makeup And Skincare Products

Comedogenic ingredients don’t necessarily create comedogenic products. If things could be more confusing, the product might contain coconut or olive oil, for example, and still be recommended for acne-prone skin. How is that possible?

It all comes down to the concentration and combination of the ingredients in the formula. 

The Concentration And Combination Of Ingredients In The Formula

When it comes to skincare products, there’s always the possibility of combining the ingredients in such a way that the comedogenic ingredients won’t be able to manifest its comedogenic potential on the skin. 

What do we really mean by this?

Well, let’s go with the most widely used - coconut oil. It’s everywhere. If you’re using pure coconut oil then you’re dealing with a comedogenic rating of 4, which means it’s very likely that the oil is going to clog your pores. But, when it’s used in a moisturizer at only a 1-2% concentration, mixed with other beneficial ingredients, the outcome changes. The oil is diluted and it’s very likely that it won’t be strong enough to actually produce such an influence on the skin as to block the pores.

The X Factor

When it comes to comedogenicity there’s also the “X factor” - like an individual’s genetic predisposition, specific intolerance and allergies that also influence the skin’s reaction to a certain product. 

The comedogenic rating of the ingredient or product determines the likelihood of comedones breaking out, but at the end, whether your skin would really breakout from using that product or ingredient is also determined by that individual “X factor”. 

In other words, we’re all different, and we might not fit the comedogenic scale as it’s intended. 

So, our advice is to use it as a flexible guide rather than a rigid set of rules, experiment, do patch tests before applying new products (preferably on the inner fold of the elbow), and you’ll be on your way to finding the best product for your skin. 

Comedogenic Tests For Makeup And Skincare Products

We went over the studies and scientific reviews that look into the composition of one ingredient to determine its comedogenic rating. But, what about products formulated of many ingredients, more or less comedogenic, as well as other substances?

In this case, we mostly rely on the tests conducted by the companies themselves or third parties. There’s no standardized or regulated testing method by any governmental organization, so results can vary greatly from ingredient to ingredient and even from brand to brand.

If you’re interested to learn more about makeup products and what specific ingredients to avoid, you should check out our two articles on the subject: “Does makeup cause acne?” and “Makeup ingredients to avoid”. 

The two most famous and frequently used methods for testing products are: 

Rabbit Ear Test

Originating from the 1970s the rabbit ear test has long been the standard for testing new products before releasing them commercially. Because a rabbit's ears are extremely sensitive, ingredients are swabbed into the inside part of the ear, and the results are assessed after two weeks. 

Although similar and much more sensitive, the rabbit's ear is not the same as human skin, which brings into question the reliability of the test. Plus, there’s always the unethical aspect of the procedure, due to animal cruelty. 



Human Skin Tests

The human skin test is usually performed on the backs of human volunteers. After 4-8 weeks their skin is analyzed so the testing team can reach a conclusion on the efficacy of the product.

The problem is that the skin on our back is thicker and less reactive than the skin on our face, which can produce inconsistencies with the results and real-life applications. Plus, studies on human volunteers are usually really small and there’s always the concern that most skin types are not well represented. 

Final Thoughts

If you were looking for an easy answer to this massive and overwhelming subject, we’re sorry to disappoint you. We know it can be a lot to take in, but oversimplifying something so complex can lead to the wrong conclusion about the nature of the natural ingredients and products that we’re using on our skin daily.  

So, in this context, a “non-comedogenic” label is probably safer for sensitive and acne-prone skin, but it won’t be a guarantee that you’ll get the results you want. Your skin can still react adversely.

The best advice we can give you is to take a look at the comedogenic index scale. Always look at the ingredients in the products you’re buying. Never forget to do a patch test before introducing a new product to your skin, and observe how your skin reacts after applying a certain product. Sooner than later, you’ll find something that works best on you.