Exploring Comedogenicity in Skin Care Products
Read Time: 3-5 Minutes
Whether browsing products in stores or researching beauty trends online, skin care enthusiasts likely come across the terms “non-comedogenic” and “comedogenic” fairly often. But what exactly does comedogenicity refer to, and how can understanding it help us make better skin care choices? In this post, we’ll delve into the details of comedogenicity and what it means for your skin.
What does “comedogenic” even mean?
People prone to acne are probably familiar with those pesky little bumps, or papules, that often appear on the forehead or chin; these are called comedones, which form as a result of excess sebum production. This blocks the sebaceous duct and hair follicle, thereby causing acne. Open comedones are referred to as blackheads, while closed comedones (blocked follicles) are referred to as whiteheads.
How is comedogenicity measured?
The comedogenic rating system measures the likelihood of a product clogging pores. Skin care products can be rated on a scale of 0 to 5 to help consumers make informed decisions about their purchases. The rating system is as follows:
0 — Will not clog pores
1 — Low likelihood of clogging pores
2 — Moderately low likelihood of clogging pores
3 — Moderate likelihood of clogging pores
4 — Fairly high likelihood of clogging pores
5 — High likelihood of clogging pores
Despite the seemingly straightforward nature of this system, the efficacy of various types of comedogenicity testing remains contested in the dermatology and skin care community, and the FDA does not publish any list of ingredients which must be excluded from products in order for them to be labeled “non-comedogenic.” In fact, there is no independent agency in the United States responsible for verifying non-comedogenic claims on skin care and makeup products, and no official testing is conducted.
Then how are ratings determined for different products?
When skin care and makeup companies claim that their products are “non-comedogenic,” it simply means that they contain no ingredients known to clog pores. Many companies use this term loosely to guide consumers toward products specially formulated for acne-prone or oily skin, so it can be hard to determine which products will be non-comedogenic for your skin.
The American Journal of American Academy of Dermatology has published a list of ratings for various oils and waxes, but determining the comedogenicity of products containing multiple ingredients can be more challenging. Companies label products as non-comedogenic based on studies published in academic journals, but in an industry with so many varying opinions and methodologies, it’s difficult to determine the validity of companies’ claims.
Why aren’t all comedogenic studies reliable?
Although skin care and makeup companies generally base non-comedogenic claims on peer-reviewed studies, there is no single, universally accepted way to test for comedogenicity, just as there is no definitive, FDA-published list of non-comedogenic ingredients. There are various guidelines available online outlining the comedogenicity of various ingredients, but these can be unreliable as well; ratings often vary from list to list and company to company.
Plus, formulas can’t be judged solely based on the sum of their parts; a single ingredient in a skin care product may be comedogenic, but that doesn't mean the entire formula is comedogenic. Some extraction and processing methods can even change the comedogenicity of certain ingredients.
For years, the skin care and beauty industries have depended on the rabbit ear test, but the reliability of this method has also been called into question for various reasons over the past several years.
What is the rabbit ear comedogenicity test?
First used in the 1950s to test industrial chemicals, the rabbit ear test quickly became the go-to testing method for cosmetics after Dr. Albert Kligman and Dr. James Fulton pioneered it for this specific use. Through this method, scientists apply ingredients to rabbits’ inner ears—which are more sensitive than human skin and respond faster to comedogenic ingredients—in order to observe the effects and determine whether or not follicular keratosis (excessive production of the keratin protein in hair follicles) was occurring, which, in turn, can lead to acne.
These original tests focused on 12 ingredient categories: lanolins, fatty acids, alcohols and sugars, waxes, thickeners, oils, pigments, silicones, sterols, vitamins and herbs, preservatives, and miscellaneous. Ranking was done based on the 0-5 scale discussed earlier, with ingredients causing large comedones ranked in the 4-5 range. During this time, the term “acne cosmetica” was coined, referring to breakouts caused by the use of cosmetics.
Why do some people consider this method unreliable?
In more recent years, some experts are calling into question the legitimacy of the rabbit ear test, saying instead that it should be used only as a guideline for clinical treatment programs. Others state that comedogenic acne cannot always be blamed solely on cosmetics, as hormones, birth control, and pregnancy can also cause these types of breakouts.
Criticism is generally centered on the assumption that rabbit ear and human skin reactivity are close enough to warrant definitive comedogenicity claims, since the effects of ingredients on rabbit ears cannot be conclusively, scientifically tied to the effects seen in humans. In fact, later studies by Fulton produced results in which some previously tested ingredients’ comedogenic ratings drastically shifted.
Are other methods available for testing comedogenicity?
With many consumers now placing more on emphasis on animal-friendly products, human testing methods have become more and more popular in recent years. Although site application varies by lab, many studies test ingredients on subjects’ backs; some experts state that this is unreliable, as skin on the back will not necessarily respond in the same way as facial skin.
How can consumers be sure of what they’re buying, then?
The comedogenicity of an ingredient is largely determined by your unique skin chemistry; ingredients that cause your skin to break out may be wildly effective in clearing up someone else’s skin. Various factors, such as exposure to different environmental conditions and the unique composition of your skin microbiomes, or microorganisms, can affect how your skin responds to certain ingredients. The original source of the ingredient can also make a difference, as varying types and quantities of chemicals may be present depending on how and where the ingredients were extracted.
It would be nice if there were more clear-cut guidelines, but the best way to keep your skin balanced and healthy is to opt for natural ingredients whenever possible, and keep things simple. Even Kligman, the pioneer of the comedogenicity scale himself, said, “One cannot determine from a reading of the ingredients whether a given product will be acnegenic [comedogenic] or not. What matters solely is the behavior of the product itself.”
It’s important to remember that just because an ingredient is comedogenic doesn't mean it’s bad for your specific skin type or will definitely cause acne; drier skin types may benefit from some formulas that cause breakouts in acne-prone skin types. And, as touched upon earlier, many ingredients’ comedogenicity shifts when processed or extracted in certain ways, and combining certain ingredients can even turn a comedogenic ingredient non-comedogenic, and vice versa.
To keep pores clear while warding off free radical damage, try our Anarose Hydrating Rose Toner. Containing hydrating Hyaluronic Acid, naturally exfoliating Willow Bark Extract, and anti-aging Goji Berry Extract, this pH-balancing, gentle toner is designed to refresh, hydrate, and prep the skin for subsequent products.