supplements for weight gain?

Does anyone know of supplements that have helped to gain weight? I gain weight when I start working out. Last time I stopped, combined with stress, I lost about 15 lbs in about a week (even then my friends didn't think I had any weight to lose). I even tried a shake that was supposed to help me gain weight and all it did was make me lose more. My husband is a little over 6ft. and weighs 135, (I know that it's too little for his height). He lost about 20 lbs after doing a parasite/bowel/liver cleanse. It's not like he doesn't eat. Last night he had 3 hamburgers. Anyway, I know that when I need to gain weight, I go to the gym but I can't get him to the gym. Again, my question, Is there a supplement that helps? Tweet