I'm the person that commented the one starting with "I'm a health proffesional" comment It turms oit I'm wrong some steroid drug names end eith -zone that is why But for the correct answer if we are talking about the opoid drug methadone here it is from the web Does Methadone makes you gain weight? Reality: Not everyone gains weight when they go on methadone, but some do. This is usually because methadone improves your health and appetite, and so you eat more. If you've been using drugs for a long time, you may be underweight and need to gain a few pounds.