Several days ago I purchased a sample of Wu-Yi (RARE) tea, only to discover after getting a 60-day sample that it is 'oolong' tea, which is not RARE.
First oolong is not rare. Secondly, you must be extremely careful of any tea that says it is a slimming tea.
I had my wife brew a cup of WU-YI for me this morning and the taste is quite robust. It is not a cheap tea but I would not pay $30 for a 90-day supply for tea that is not sealed and not organic.
Please avoid drinking any tea immediately after taking medication - wait 1-2 hour. You see most teas do absorb fats and if taken too soon after taking medication it will also absorb some of your medication which may cause problems.
There are slimming teas but they act like those usually work by being strong diuretics and laxatives, so you'll drop a lot of water weight quickly, but not only will you have to deal with problems related to dehydration, many of them can mess up your digestive system irrevocably. Cutting out fats and sweets and switching to non-soda drinks (which tea can help you do!), plus getting out for a walk every so often is a much healthier--and effective--method.