I don't think that there really are any major sides with t3. It has been around for a long time and used by folks for decades. There was even a study that looked at folks who were incorrectly diagnosed and put on t3 for years. When they stopped taking it, they flipped back to normal in a few weeks. \
You should ramp up and then ramp down so your body adjusts and doesn't start packing on the weight when you stop taking it. I add a pill a week and then drop back a bit faster (they recommend the same steps going down.)
Clen can give you heart palpatations if youtake too much. The only side I have experienced is muscle cramps in weird muscles (my neck and forearm for example). Take potasium and magnesium and suck it up for a couple of weeks. The cramps never caused any probelms in my lifting. Don't take too muchg clen to start with or you can really fuck your self up. It is weighted in MCGs. I start with 25 mcgs and add 25mcgs every 3 days. After I get to 150 mcgs I stop since your body stops responding. YMMV, but you can tell if you are taking too much. Take it in the morning if you have any interest in sleeping at night.