Phenoxyethanol
In plain terms
A preservative that stops bacteria and mold from growing in a product. It is the most common stand-in for parabens in "paraben-free" formulas.
What the evidence shows
Phenoxyethanol is a preservative that keeps bacteria and mold out of a product, and it is the ingredient that most often fills the gap when a formula drops parabens. For adult skin it has broad backing: Europe's safety committee, the FDA, Japan, and Health Canada all judge it safe up to a 1% cap, and large patch-test surveys put the rate of skin allergy below a quarter of one percent, rare enough that reviewers called it barely an allergen at all. Where it turns conditional is the very young. In 2008 the FDA warned against a nipple cream containing it, because phenoxyethanol can reach a nursing infant and slow the nervous system, with vomiting, reduced feeding, and drowsiness; the agency said to keep it off the chest while breastfeeding. France's medicines agency went further and advised against it in diaper-area products, including wipes, for children under three, a stricter line than the EU committee took. So the split is by who is using it and where: a 1% preservative in an adult moisturizer is well supported, while products meant for infants, the diaper area, or nursing are where the caution sits.
On the label
Listed as phenoxyethanol or 2-phenoxyethanol. It is often what "paraben-free" means in practice, so that claim by itself does not make a product gentler or preservative-free.