Timbo - I did a report on ephedrine for an upper division sports nutrition/supplementation course in university last year. If I remember correctly the stimulatory and side effects of ephedrine (anxiety etc.) experienced tachyphylaxis after about 4-6 weeks, but thermogenic effects lasted around 20 weeks. As a side note - my prof did not approve of my conclusion that "when used by a healthy population in proper dosages, ephedrine can be a safe and effective supplement for weight loss". She told me that I should keep my personal opinions out of my presentations and papers. I pulled out my research, backed up all of my points, then told her that she shouldn't allow herself to be influenced by the media when marking papers - and should stick to the science. Although annoyed by my impertenance (sp?), she still gave me and A.