Speaking broadly, any expiry date you see on a bottle of e-liquid is ultimately an estimation. This is because in the absence of FDA regulation there is no established use-by date for a bottle of juice, but that doesn’t mean that the listed dates are inaccurate.

The use-by date of any bottle of e-juice is likely to be listed as anywhere between one and two years. This is based largely on the established shelf life of nicotine, PG and VG of around two years (as long as they’re stored below 104 °F / 40 °C and away from UV light; VG keeps best at around 77 °F / 25 °C), but they aren’t the only contents of e-liquid.

The flavors are the real uncertainties when it comes to shelf life, but they’re unlikely to have too much of an impact. To take a couple of examples – 2-actetylpyrazine (a nutty, chocolatey flavoring) has a shelf life of five years, and vanillin (vanilla flavor, as you may expect) lasts for about two years. Of course, there are many flavors used, so this can differ depending on the specific bottle of e-juice, but two years is generally accepted as the life-span.

The expiry date for e-liquid isn't officially established, but based on the life of PG, VG and nicotine it can be expected to be 1-2 years (when stored correctly)

“If kept out of sunlight and at room temp or cooler, the e juice should keep for years.  If exposed to oxygen the nicotine may become darker but will still be fine. Sun light will break the nicotine down. In some cases the flavor additives may turn on you but that can vary depending in what your using - I had roast beef e juice become road kill e juice and it wasn't pleasant lol.  I keep all my e juice in the fridge and its never been an issue ”