Would growth hormone treatments be benificial in a adult where most of their muscle mass was eaten by their body because their weight got so low?

It may be: Helpful but isn't standard of care. There are many options to get body weight up. Growth hormone can have a downside. Why have you lost the weight? Is it due to anxiety or is there another process? Mirtazapine 15 mg at night helps sleep, anxiety and appetite. Without knowing your condition, assuming stress, try this and wt bearing excercises, need 2 see doc, look up mirtazapine, bring info.

Unproven danger: This is something used, poorly, by athletes to improve muscle mass, but it is not approved or indicated for people whose muscle mass is low and we don't know the long-term effects. Better to slowly regain muscle with the aid of a good nutritionist, and a physical trainer. Avoid the hormones - because even if you had them you would still need a nutritionist and trainer.