Maybe I'm just cynical but this seems suspiciously like snake oil. Seems impossible to exclude the placebo effect and the improvements are self reported (more or less).

CK2, what makes you think that FDA cleared only means it’s “extremely similar to other approved devices”?

I think you may be confused, or are repeating something you heard in a Netflix documentary.

First, “fda cleared” means your device is “substantially equivalent” to another cleared or granted device. You can’t be cleared based on another approved device, since approval means the other device received a PMA. Second, substantial equivalence is actually quite lenient. I know, because I’ve helped clear over 50 devices.

Finally, a cleared device still can require a lot of testing. Frequently FDA requires our clients to run multimillion dollar studies to validate their devices.

Is that true with the 501(k) approval?