So I've known my buddy for 5 years now and he can't put any body fat on himself. He is 5.5 and skinny as a stick. He eats like a pig. Can eat up to 4000 calories a day. He asked me how he can put weight on and I suggested mass gainer in addition to his calories. He's been on it 3 months and still hasn't gained weight. Does anyone have suggestions? Some sort of peptide or research chemical that would help him gain weight?