Deca converts to dihydronandrolone which is a very weak androgen and will block DHT from it's receptors in the scalp by competing with it. Honestly though, DHT makes me and most of the people I know feel great. I would accept the hair loss, build up the neck muscles, and shave your head and keep your DHT levels high to feel good.
Nizoral shampoo and rogaine are good topicals too for delaying hair loss.