What a 1/5 rating means
On the comedogenic scale, a 1 sits at the safe end of the scale — clogging is unlikely for most people. That places PEG-400 in the range most people, including many with acne-prone skin, tolerate well.
One thing the number cannot tell you is concentration. Ingredients are listed in descending order, so PEG-400 near the end of a label is present in tiny amounts and matters far less than the same ingredient near the top.
About PEG-400
It is a solvent used to dissolve other ingredients or aid drying. A low-molecular-weight polyethylene glycol used as a water-soluble solvent and humectant. Rated 1 on the Fulton-derived table; PEGs in this size range are generally well tolerated on acne-prone skin.
On a label it can read as Peg 400, Peg-400, Polyethylene Glycol 400, Polyethylene Glycol — worth knowing when you scan an ingredient deck.
PEG-400 in makeup and skincare
It is used in liquid liners, nail products, and some cleansers. Its irritancy is rated separately at 0/5, which is low.
PEG-400 comedogenic FAQ
Is PEG-400 comedogenic?
Not usually. PEG-400 is rated 1/5, which is low risk on the 0–5 comedogenic scale, so it is unlikely to clog pores for most people, including many with acne-prone skin.
What is the comedogenic rating of PEG-400?
PEG-400 has a comedogenic rating of 1/5 (low risk). Of the 190 ingredients in our dataset with a published rating, 132 rate higher than PEG-400, 28 rate lower, and 29 others share its 1/5. Among the 3 rated solvents, none rate higher and 2 lower. The figure is drawn from 1 cited source, listed on this page.
Is PEG-400 pore-clogging?
It is unlikely to be. At 1/5, PEG-400 sits in the range generally treated as non-comedogenic. Concentration still matters: an ingredient near the top of a label makes up far more of the product than one near the end. Comedogenic ratings come mostly from rabbit-ear assays and small human patch tests of the pure ingredient at high concentration, so they are a screening guide, not a prediction for your skin or a medical claim.