You are correct..it is a small amount, it is very powerful stuff. When I start 20mcg has me shaking like a leaf, but after 10 days I am up to 200mcg. Start small and work your way up.
As was said before, due to the small dosing an insulin syringe is perfect for this.
Probably want to get some taurine too, clen scavenges taurine. Clen cramps suck ass.