do I need a license?

as part of some of my training courses, I make up kits for the students.
At the moment I give them preblended essential oils which are diluted, and an ubtan (dry powder).

I am aware that they will want to buy products in bulk, but I don't want to give my recipes away.

Do I need to have a license to sell to students that have undertaken training and then are qualified to do the therapies? I don't want to sell to the public.