Actually, It is the other way around.. THCA (non psychoactive) into THC ( psychoactive ).

This website http://herb.co/2015/10/11/how-to-decarboxylate-cannabis-and-get-higher-from-edibles/ shows THCA stripped of a C0² by decarb to become THC

This website will also help you with conversion on how to read lab results.
http://hightimes.com/grow/thca-vs-thc-how-to-read-a-lab-result/

https://www.herbanoids.com/homepage/
http://stratosthc.com/
These last two links are some other types of marijuana pills that are getting popular.