I'm fed uo with my scalpy flake. None of the special shampoos work.
I find sunshine works well, especially if combined with salt water. A week on a beach, & the worst attack goes away completely. In winter, getting up high in the mountains for maximum UV is good.
Steroid shampoo prescribed by my GP is also effective, but not to be used all the time.
The old coal tar stuff used to work well enough, but was taken off the market. The chemists-only stuff you can get now isn't as good. Probably not as carcinogenic, either, but when my scalp's sore & red & weepy (luckily rare: itchy & flaky is usually as bad as it gets) I don't care: gimme the carcinogens!