Cyproheptadine
"Periactin (Cyproheptadine) is amazing for weight gain! I gained so much weight and I looked amazing, however there were three side effects 1) I slept like a bear, I was always tired 2) I had really bad mood swings, and I was like a zombie 3) dry nose bleeds. However I reduced the dosage from 2 tables (one in the morning, one at night) to one a day and I felt much better. I recommend you take multi-vitamins and do lots of exercise. The results were quick and amazing, I would recommend it to anyone who wants to gain weight."