Does anyone know if something like this is required to be approved by the FDA? Like if someone were to make one for the hobbyist/weight loss market, would that even be legal?

It depends on intended use. If it is to diagnose, cure, treat, or prevent a medical condition then it is a medical device that may need approval. If it's not intended for anything medical, it doesn't need FDA approval. For example, clinical thermometers are class II medical devices, lab thermometers aren't medical devices at all. If the device were genuinely only marketed for general wellness, it would be exempt.

Basically yes, take a look at the not for human consumption drug, sorry medicine market.

Was analogs in the 2010s, Obama had to pass the analog act low… now it’s back with peptides and glp 1 which aren’t scheduled but..

Yeah I guess make enough money and then lobby for the benefit of your audience base or for future proscuation