The list

Pore-clogging ingredients

Reviewed by Elysiana, master esthetician

These are the 99 ingredients the checker flags. 77 are known pore-cloggers, the ones to skip if you break out easily. The other 22 clog pores for some people and not others, so they are worth watching rather than ruling out.

Where an ingredient sits on the label matters as much as whether it is here. Lists run from the most used to the least, so a pore-clogger in the first five names is doing far more than one trailing at the end. The checker reads a whole label at once with that in mind.

Highly comedogenic

Known to clog pores. Grouped by what they are, since the oils and the esters tend to travel together on a label.

Esters, emollients and emulsifiers

Fatty acids and fatty alcohols

Lanolin and animal fats

Algae and seaweed

AlgaeMarine algae / seaweed

Everything else

Use with caution

Clog pores for some people. Fine in many formulas, and the first suspects when a product with nothing worse in it still breaks you out.

Using the list

Nobody memorizes 99 names. The list is here for a second look at one ingredient; for a whole product, the acne ingredient checker does the reading, catches the spelling variants and the 111 names algae goes by, and tells you how much of the label it recognized.

Every ingredient we rate, flagged or not, is in the full index, and what comedogenic means covers why a flag is a reason to look closer, not a verdict on its own.