My GF of 3 years knows, shit I get her to pin me, women wants to be a doctor so I let her practice on me. We support each other in everythingy and I also agree honesty is key. Just sit her down and tell her everything you know, side effect and all that jazz. She has used it over my head whileist during pct but that was probably legit and I was being a little bitch. She now has started researching on her own for her first cycle.