After poring my nose over the different resources available online, I came upon a study by James E. Fulton etal., which has probably become the main reference of manufacturing skincare products. This study tested several ingredients commonly found in skincare products on a rabbit's ear to see if they can result to the formation of comedones. This is based on the premise that the presence of a comedogenic ingredient makes a product comedogenic overall.
For the ingredients that were used in the study, a rating of 0-5 was used to indicate the level of comedogenicity, where 0 means noncomedogenic, and 5 as highly comedogenic. You will also see another scale pointing to level of irritancy of the ingredients, where 0 means non-irritating, and 5 as highly irritating. Note that a rabbit's inner ear is thinner and more sensitive than human skin, thus, some mildly rated ingredients might not be comedogenic to human skin at all.
List of highly comedogenic ingredients (4-5/5):
Acetylated Lanolin Alcohol
Cetearyl alcohol + ceteareth 20
Cetyl Acetate
Cocoa butter
Coconut butter
Ethylhexyl pelargonate
Glyceryl-30-diisostearate
Isocetyl Alcohol
Isopropyl isotearate
Isopropyl linolate
Isopropyl myristate
Isopropyl palmitate
Isopropyl isostearate
Laureth-4
Lauric Acid
Myristyl lactate
Myristyl myristate
Oleth-3
Oleyl alcohol
PEG 16 Lanolin (Solusan 16)
Polyglyceryl-3-diisostearate
PPG 5 Ceteth 10 phosphate
Steareth-10
Stearyl heptanoate
Xylene
List of moderately comedogenic ingredients (3/5):
Avocado oil (2)**
Butyl stearate
Corn oil
Cotton seed oil
D&C red #3
D&C red #17
D&C red #30
D&C red #36
Decyl oleate
Dioctyl malate
Dioctyl succinate
Evening primrose oil
Glyceryl stearate SE
Hydrogenated vegetable oil
Isodecyl oleate*
Isotearyl neopentanoate
Laureth-23
Mink oil (2)**
Myristic acid
Oleth-5
PEG 8 stearate
PEG 200 dilaurate
PG monostearate (0-3)
PPG 2 myristyl propionate
PPG 10 cetyl ether
Sesame oil (1)**
Shark liver oil
Sorbitan oleate
Soybean oil
Stearic acid*
Stearic acid: TEA
Sulfated jojoba oil
Tocopherol*
Wheat germ glyceride
Vitamin A palmitate*
Water-soluble sulfur
(Note: * depends on source of raw material; **number in parethesis indicates results for "refined" oil)
List of irritating ingredients (3-5/5):
Caprylic acid
Ceteareth-20
Ethylhexyl pelargonate
Isocetyl alcohol
Isopropyl myristate
Isostearyl neopentanoate
Laureth-4
Myristyl alcohol
PEG 16 lanolin (Solusan 16)
PG laurate
Steareth-10
Tocopherol*
Tridectyl neopentanoate
Vitamin A palmitate
Xylene
(Note: * depends on source of raw material)
Now after reviewing the list, I've realized I have been using many skincare products containing many highly comedogenic ingredients. I had made sure all my products contain the "noncomedogenic" label, but as I've found out, having such label doesn't mean they are completely free of these ingredients. It is important to note though that it might be premature to conclude that having comedogenic ingredients result to comedogenic products. It is probable that certain combinations of compounds reduce the likelihood of clogging pores. Certain major offenders though, such as isopropyl myristate, acetylated lanolin alcohol, lauric acid derivatives such as laureth-4, should be used with caution. The researchers did not believe that using a lower concentration of the aforementioned offenders would make the overall product less likely to clog pores. For the overall comedogenicity of skincare products, it was suggested by the researchers that more tests should be done in the future.
Perhaps companies have already been conducting their own tests, only that they don't publish the results for the public eye. Watching out for each and every ingredient is indeed a tedious task. So I've decided, as long as the product didn't break me out, I would continue to use it, despite the inclusion of comedogenic ingredients. On the other hand, if you do know other publications regarding comedogenicity, feel free to share it here.
If you're interested to read the entire research, here's the link:
