I would see if you can find out how much grapefruit juice is actually in the seltzer and then cross reference with studies on grapefruit juice.
This one talks about the effect of even a single glass of grapefruit juice. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3589309/
It doesn’t have any juice, but I don’t know what goes into the flavors they use and whether that’s also going to affect medication.
La Croix’s website says they use grapefruit oil. Poking around, it appears to interfere a lot less than juice components, and with how small of a quantities is in seltzer’s I would be very surprised if there was any appreciable interaction.
Are most seltzers flavoured by vaguely waving a fruit in the direction of the water?
I do know a lot of natural flavors don’t contain anything from the substance they’re imitating lol.
Today I learned that Dan Aykroyd has both Aspergers and Tourettes. He is also a Spirtualist and UFOlogist and his great grandfather was pen pals with Sir Arthur Conan Doyle. So…the more you know.
Well if Dan A believes in aliens, that’s it. They’re real.
He should know.
Do people really not believe in aliens? That never made sense to me. The universe is too big.
There’s believing in aliens, and then there’s… Believing In Aliensss 
Oh to clarify, I definitely do, I’m on my third personal rewatch of X-Files lol. But I think the answer lies in your question—universe is big enough to have aliens and people who don’t believe in them!
In the old Dune movie, the sand worms were miniatures. But then regular sand looked huge, so they had to use special fine ground glass that necessitated the use of hazmat suits.
SERATONIN IS THE PRECURSOR TO MELATONIN. WTaF! That makes so much sense and now I’m mad I didn’t realize this 
Yasssssss and I am honestly totally mystified you don’t already have this in your physiology memory bank!!! It’s one of the big reasons I quit caffeine every winter 
Husband didn’t either and he has a Biochem degree! It’s even in the naming convention and I’m kicking myself for not logging that away I HAD to have learned that some time.
So we make seratonin and it turns into melatonin and then we sleep?
I have no human biology except what I’ve picked up over the years this is a real question plz
Very short version, yes, you need serotonin in the right place to make melatonin. Long answer is super complicated- https://www.healthline.com/health/dopamine-vs-serotonin is a good overview of all the stuff serotonin and dopamine are up to in the body.
It took me a minute to realize this was talking about melatonin and not melanin. Could not figure out what serotonin would have to do with being about to tan.
Falling asleep by the pool?
What does winter and caffeine have to do with serotonin? Is it because it’s dark so your brain is not producing as much serotonin?
