My question is that I heard that methadone stays in your system for years. Does it? I don't believe it does. I have detoxed cold turkey off of Heroin before, 3 days tops, total hell, but I was through with the withdrawals. Methadone, on the other hand, last longer than a non-synthetic opiate; I'd say, 7-8 times longer per dose. So, I expect that my withdrawals could possibly last no loner than 3 weeks. However, I am feeling better after 13 days, not the greatest.