When you're comparing bottles, start with the basics. The FDA requires a nicotine warning statement on all e-liquid packaging. That's the yellow or black box that says 'WARNING: This product contains nicotine.' You should also see a list of ingredients, and the packaging needs to be child-resistant—that means a push-and-turn cap or a similar mechanism.

If the label lists the VG/PG ratio, make sure it's clear, like '70% VG / 30% PG.' Some brands print it on the front, others on the back. If you don't see it, that's not necessarily a red flag, but you can always check the brand's website. For a deeper dive into what to look for before you buy, our guide on VG vs PG on the Shelf: What to Check Before You Buy covers this in more detail.