I have various flavors like Hawaiian punch and root beer as the powder you put in your water to make it taste better and it says they were best by last year (2023). Is it safe to use them? I've never even opened the boxes they came in.
From the title my stupid brain thought you were looking for flavour powder that made the water taste like it was expired/old (maybe for Halloween or as a joke or something) xD
Edit: nvm, I should have just explained rather than asking and not waste your time, my apologies.
Reason I asked is that while nothing in those flavor packets spoils in a way that will harm you, nor break down into something that could, they may well taste unpleasant.
Artificial sweeteners in particular kinda get "stale", unless stored completely air free. They lose sweetness, and if the other chemicals are mixed with the sweetness in mind, it might not be enjoyable.
But there's no actual expiration date on any of the brands or their components that I've ever seen. Best by dates aren't the same thing as expiration dates (which you probably already knew, but figured I'd mention it anyway).
Worst case, it tastes like crap, unless the package has been damaged enough for moisture to get in. If the packet is intact, you're good to go. Otherwise trash it
Open it up without shaking it up or jostling it too much. Is it still powdery all the way through? If so, it's probably safe.
If you open it up and the mix has any clumps or inconsistent coloring, toss it in the trash because it's likely been exposed to moisture, which invites a ton of potential problems.
Disclaimer: I'm not a doctor, but I have made some questionable decisions with old tubs of G Fuel mix and came out alive, so I'm not just making things up but I'm also not somebody you should trust your health with. Be responsible.