Skin Chemistry: Comedogenicity

  • Apr, 09 , 18
  • Bridgett Gordon

Comedogenicity sounds like a word that might be related to comedy but when it comes to taking care of your skin this word isn’t funny! Comedogenicity refers to an ingredient that can cause blackheads (comedones) in a short time period. When the outer layers of our skin don’t sheat properly causing blockage of the hair follicle, blackheads form. Oxidized fatty acids on the surface of the skin creates the blackhead. The exact cause of this phenomenon, desquamation) isn’t exactly clear.


There is a healthy debate about whether comedogenic scores are useful because a rabbit model was used to give scores concerning ingredient comedogenicity. The argument is that the rabbit ear model can’t relate to comedogenicity for human skin. Also, comedogenic levels of ingredients may possibly change once substances are combined. It has proven that some ingredients can lower the comedogenicity levels of other ingredients.


Fortunately, the rabbit model for testing comedogenicity is being phased out or forbidden and has been replace by human volunteers. While Comedogenic charts can be useful, it is important to understand that different people may react in different ways to ingredients and comedogenic levels. Shea butter is universally touted as an awesome moisturizer and it has a comedogenic level of a zero. Sounds great but it still may give your skin problems. And vice versa, an ingredient that is high on the comedogenic chart like coconut butter may not cause skin issues at all.


Consider the fact that comedogenicity isn’t just about oils. The type and quality of surfactant, humectant and oils in your products can all cause skin issues.

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