Occaional use of Head and Shoulders or Selsen Blue.
Dread Products
Dandruff can be caused either by a dry and irritated scalp or a fungal infection of the scalp.
If it's dry and irritated scalp it's likely that "regular" shampoo won't actually help in the long run. It'll "look" like it helps because it often contains things that cause the loose flakes to stay glued to the scalp and won't let 'em fall off naturally.
Also, "regular" shampoo ('specially if you use it more than once a week) removes all the natural oils from the scalp and it "burns" the sebum glands so they produce less natural oils for a little bit which causes the scalp to become irritated because it's too dry.
The solution to this is to wait it out really.
That is to say. Stop all "regular shampoo" use and wash only every 3-4 days with something much milder than regular soaps.
It'll get a lot worse for a couple of weeks, but then all of the sudden you'll realize it's gotten a LOT better.
Now, if it's fungal, it won't actually get better unless you deal with the fungal infection and not just it's symptoms.
Most anti-dandruff shampoos only deal with the symptoms which is why it returns the moment you stop using them.
For actually treating the infection you need a proper medicated shampoo from the pharmacy "or" if it's merely a mild infection, adding certain oils to your BS wash "can" be enough.
Since it's apersistentproblem which you feel you "need" anti-dandruff shampoos to address it's likely it's fungal. This does NOT mean you have to comb out your locks, it only means you'll have to treat your scalp and then be patient while it heals (as after treating the fungus it'll take a while to recover from years of exposure to the harsh chemicals in shampoo along with the years of fungal infection).
I'd suggest getting a medicated shampoo, watering it down a little bit (so it can soak in good) and washing with it every 3-4 days until you're out of medicated shampoo, then switching back to the bs wash (again, 3-4 days apart) and giving it about 1-3 months and "then" seeing if you haven't cleared up good.
Also, rinse rinse rinse rinse rinse!
When you think you've rinsed everything out of your hair, rinse twice more.
Most of us don't actually rinse our hair well enough when we wash it.
So.. yeah...