Given the current state of common food I don't think I would agree that it's currently over-regulated.
Then you have dietary supplements which is a complete wild west. There's a 3 billion dollar kratom industry, for example. You can buy this dangerously addictive drug at your nearest 7-11 or gas station.
R/quittingkratom has tens of thousands of members. So hundreds of thousands of people have had their lives seriously affected by it (every addict ruins multiple lives... Family and friends). That's to say nothing of the many dead from kratom.
There are many subreddits related to quitting various things. If that's your metric for “lives ruined" there are dozens of other things that have ruined dozens of times more lives.
2. Yeah its may be unhealthy but people do all kinds of unhealthy things to themselves.
3. 35k subs on a subreddit that seen around 12 years is TINY. There's a sub about quitting porn that has over a million.
4. Even though you claim there are "no studies", here's a study from the WHO. Where they concluded that no action beyond "monitoring" was warranted based on current evidence.
https://www.who.int/publications/m/item/kratom-mitragynine-7...
I wonder if they will legislate on that soon.