According to Michelle Calvarese PhD., a comedogenic ingredient clogs pores by increasing the keratin production in hair follicles. This process can occur quickly, or over a period of months, and is influenced by many factors, including the enzymes and genetics of each person. Human sebum is a comedogenic substance, and avoiding ingredients that are prone to “clogging” is not prevention. Many “comedogenic ingredient” lists online lack scientific testing protocols, however, a common list of tested comedogenic ingredients include:

Acetylated Lanolin Alcohol, Butyl Stearate, Cetyl Acetate, Coal Tar, Coconut Oil, Ehtylhexyl Palmitate, Glyceryl-3 diisostearate, Isocetyl Alcohol, Isopropyl isostearate, Isopropyl linolate, Isopropyl myristate, Isopropyl palmitate, Isostearic acid, Linoleic acid, Laureth - , Lauric acid, Linseed oil, Myreth-3 myristate, Myristyl lactate, Myrityl myristate, Octyl palmitate, Oleic acid, Oleth-3, Olive oil, PEG 16 lanolin, Polyglyceryl-3 diisostearate, Steareth-10, Squalene, Stearyl heptanoate, and Xylene.

The extraction process of an ingredient, and combining ingredients can have direct effects on the comedogenicity of a substance, and can turn a non-comedogenic substance into one that is comedogenic. As a result, regulatory guidelines from the FDA do not include of list of comedogenic substances, but merely a definition of a comedogenic ingredient as being one that clogs pores.

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