Make sure to emphasize that men should not stop shampooing if they have long hair. I tried going cold turkey a couple of months ago and it got nasty pretty quick. Tons of dandruff, insanely greasy, split ends, damn. It was awful. Back on the shampoo now and will be for a while. I only use it after I exercise in a swimming pool with chlorine. If you have longer hair (3+ inches everywhere) do not stop shampooing, wait until you decide to have short hair again to cut shampoo.
Also for a lot of people, the dandruff gets really bad for a while. Much longer than 2 weeks. You will eventually have a healthy scalp and pretty hair, but be prepared to avoid dark colored shirts for a month or two.