Introduction
In this blog we will be discussing what comedogenic means, the background of the term, and why it's relevant in cosmetics. We will also be looking into the 1989 report by James Fulton who conducted testing of ingredients to determine the comdogenicity and irritancy of a range of ingredients this report is commonly used in the industry to develop non comedogenic cosmetics. We will also be showing you the comedogenic scale and how we used it to determine the comdogenicity of ingredients. Lastly we will be discussing the regulation of the term.
What does the term comedogenic mean?
Comedogenic means that a product is likely to clog skin pores, which can then lead to acne lesions. Non-comedogenic means that a product is not likely to clog pores. The root word of each term is comedone, which is the medical term for a clogged pore. Natural processes in our skin can leader to clog pores but ingredients in cosmetics can sometime be the culprit as well. (Kern, 2023).
The background
Comedogenicity is an important consideration in the development of topical medications, cosmetics, and skin care products. The concept of "acne cosmetica" was developed to link the use of certain ingredients to comedo formation. Animal models were originally used to determine the comedogenic potential of raw materials with the assumption that finished formulations containing these ingredients would also be comedogenic. Based on this assumption, dermatologists were presented with lists of substances to avoid in patients with the ability to develop comedones. (DiNardo & Draelos, 2006).
How comedogenic a cosmetic product is especially relevant if you suffer from acne prone skin, as these comedogenic ingredients can aggravate acne on the skin. Acne vulgaris is one of the most common conditions for which patients seek dermatological care and is estimated to affect between 40 and 50 million individuals in the United States. (Callender & Davis, 2010). With acne affecting so many people it’s important as formulators and consumers we are aware of what ingredients clog our pores so we can avoid them.
Comedogenic scale
This concept of comedogenicity led to the development of a comedogenic scale:
0: Non-comedogenic - substances with a very low likelihood of clogging pores.
1: Low-comedogenic - substances with a low likelihood of clogging pores.
2: Moderately comedogenic - substances with a moderate likelihood of clogging pores.
3: Comedogenic - substances with a higher likelihood of clogging pores.
4-5: Highly comedogenic - substances with a very high likelihood of clogging pores.
When formulating cosmetics for those with acne prone skin or oily skin types, we use the comedogenic scale as a point of reference to determine which sort of ingredients we can formulate with. It is also important to note that using multiple non comedogenic ingredients can still result in the finished product being comedogenic. For this reason it is recommend to keep the ingredients you are using to a minimum, it’s very difficult to know how to finished product will react on the skin whether it will in fact be skin clogging. We will only be able to determine this by testing the products on human skin.
How do we determine the comedogenicity of ingredients?
In 1989 James E. Fulton published a report where he tested the comedogenicity and irritancy of several groups of cosmetic ingredients on rabbit ears. This is commonly used in the industry to determine how comedogenic ingredients are. The report is limited in that quite rightly the testing of cosmetics on animals is illegal in most parts of the world, therefore there are several ingredients we do not know what the comedogenic rating is and we would have to test on human to determine this. Secondly the rabbit ear is a lot more sensitive than the human skin so it does not accurately reflect how these ingredients will act on the skin. Certain generalisations can be deduced by examining the results. Medium chain length fatty acids are more potent than short long chain fatty acids in producing follicular keratosis. The comedogenicty and irritancy of an organic material can be reduced by combining the molecule with a polar sugar or a heavy metal, increasing the degree of exthoxylation in a molecule tends to reduce the comedogenicity and irritancy of the chemical and the longer chain lipids ie. waxes appear too large to produce a reaction. By following the guidelines developed in this study, it is possible to formulate non irritating, noncomedogenic moisturisers, sunscreens, hair pomades, cosmetics, and conditioners. (Fulton, 1989). You can access the full report by clicking the link in the reference list below, the report lists the comedogenic rating of several cosmetic ingredients.
Regulation
Many cosmetic products on the market are marketed as non comedogenic currently this term isn’t being regulated by the FDA or the EU so unless testing has been done on humans to determine the comedogenicity of the product unfortunately there’s no way to know for sure until you use the product. And even with human testing there are drawbacks because the skin on the back where testing is done isn’t representative of the skin on the face. Before you buy a product ask the brand what clinical studies have been conducted to support any non comedogenic claims they do make. Try buying samples before committing to larger quantities to ensure this product is right for you. As formulators try and collate the results from a sample of participants willing to test the comedogenicity of your product.
Conclusion
In this blog post we have defined the term comedogenic and non comedogenic, showed the comedogenic scale and how its used to determine how comedogenic certain ingredients are. We have also shown you the comedowns report that is commonly used in the cosmetic industry to help develop non comedogenic cosmetics and linked the reference to where you can read this in detail. Lastly we have briefly discussed the regulation of the term, I hope you have found this blog helpful!
References
Callender, Valerie D. & Davis, Erica C. (2010). A Review of Acne in Ethnic Skin. Accessed [19/01/2024]. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921746/
DiNardo, Joseph C. & Draelos Zoe D. (2006). A re-evaluation of the comedogenicity concept. Accessed [19/01/2024]. Available at: https://pubmed.ncbi.nlm.nih.gov/16488305/
Fulton, James E. (1989). Comedogenic and irritancy of commonly used ingredients in skin care products. Accessed [19/01/2024]. Available at: https://insolitbeauty.com/documentacion/Comedogenicidad%20e%20irritacion%20de%20los%20ingredientes%20de%20uso%20comun%20en%20productos%20para%20el%20cuidado%20de%20la%20piel.pdf
Kern, Dan. (2023). What Do “Comedogenic” and “Non-comedogenic” Mean. Accessed [19/01/2024]. Available at: https://www.acne.org/what-do-comedogenic-and-non-comedogenic-mean#ComedogenicExplained