Short answer: no. The FDA treats e-liquids as tobacco products, but it doesn't set a required ratio of vegetable glycerin to propylene glycol. That's a formulation choice made by the manufacturer, often balanced for throat hit versus vapor production. What the FDA does regulate is labeling, ingredient disclosure, and child-resistant packaging. So when you pick up a bottle, you should see the nicotine strength clearly stated, along with a warning label. The VG/PG ratio may be on there too, but it's not a legal requirement unless the brand makes a claim about it.

For you as a consumer, that means the ratio is more about your personal preference than compliance. If you're sensitive to throat hit or want bigger clouds, you'll likely lean toward higher VG. But don't assume a higher VG means 'safer' or 'more compliant'—it's just a different mix.