Trainers are a dime a dozen and some have fake certs. Some things I think to look for is a CSCS. That way you know they have at least a bachelor's, they've taken a test and passed a hands on practical test as well. In my humble opinion CSCS's are the best. Also ACSM is very good.
Then it comes down to "Do they listen" Do they care what you want? Do they inspire you to do more than you could every do on your own? Do they spend all of their time telling you how great they are or how great they think you are doing?
Just some thoughts. I know next to nothing about anabolics, but I've been a trainer for 9 years and I'm a cscs so maybe I'm biased, and I don't train right now due to cancer, but those are the things I would look for if I were in the market.