Cyproheptadine
"I am a retired physician who during the course of his practice treated many patients with severe anorexia secondary to HIV/AIDS as well as near end stage malignancies. For many years I prescribed Periactin starting with the 2mgm dose 1/2 to one hour before meal time. Many patients reported a robust weight gain. The hypersomnolence (excessive sleepiness) disappeared after one to three months. The Periactin can be reduced to one 2mgm every third day and the weight usually is maintained at good if not optimal levels. "