-Mine is from the Pharmacy via my TRT doc's Perscription. I can't speculate about purity concerns and how to adjust dose to remedy that effect other than to say that side effects might be a way to know that one might be administering to much. I'm normally conservative with regard to my health.
-A conversation with the pharmacy verified that I'm paying (roughly) a 100% mark-up to my doc. ...I'm getting a new doc for the next script.