(Concern) Herbal Medicine Diet

I'm curious about traditional Korean medicine dieting.

My friend said she lost 8 kilograms after taking herbal medicine, so I was curious.

Does herbal medicine formulation improve constitution and boost metabolism effectively?

Or is it to suppress appetite?

I wonder if it could paralyze the cervical spinal nerves.

I used to experience insomnia and nightmares after taking diet pills in the past. Are herbal medicines okay? I'm also curious about the yoyo effect, and I want to take them, but I'm worried about insomnia and depression.