How much clen are you taking and what other thermogenics...
I did clen for 2 weeks with the following plan and got no sides at all....no shakes nothing
Dose 1 - 15mg Yohimbine, 200mg Caffeine
Dose 2 - 40mcg Clen, 200mg Caff, 25mg Ephedrine (4 hours after dose 1)
Dose 3 - 40mcg Clen, 200mg Caff, 25mg Ephedrine (7 hours after dose 1)
Dose 4 - 40mcg Clen, 200mg Caff, 25mg Ephedrine (10 hours after dose 1)
I can't believe it. It's the first time I used clen and I thought it would kick my ass but it went fine. It was also pretty good at burning fat.