Cyproheptadine
"yes the hype is true with this med for appetite increase(also used for allergies which works wonders)
this will.. i repeat this medicine will make you sleepy, dizzy and a bit lazy the first few days...i would say give it a full week before the sleepiness becomes manageable 

i can recommend is taking 2mg then up the dose every few days **DO NOT take a full 4mg at first it will knock you on your butt
(dissolving the tablet in juice or taking it with a full meal might help with the drowsiness)
started this med at 100lbs 9 days later i'm at 108lbs

i rate it a 9 and not a full 10 because of the extreme drowsiness/sleepiness in the beginning 

one last thing i recommend is to eat healthy foods to gain weight"