Have you tries these remedies ?
https://www.healthline.com/nutrition/ways-to-treat-dandruff

I’d go visit a trichologist and get it assessed properly. As others have mentioned it could be psoriasis. Basically the PH level in your skin is off balance and I dare say that a trichologist would ecommerce some natural supplements to help you fix it. Goodluck

Have you considered not using shampoo? A friend of mine did this after she couldn’t get rid of her dandruff. Took her a few weeks to let her hair sort itself out but all she did was rinse it in water each night and once a week rubbed a bit of baking soda through her hair to remove some of the oil. She reckons her hair is great now – not oily, not flaky and theres no dandruff because her oil ducts have regulated themselves to what they’re supposed to be doing. Maybe give it a google and see what other people have said and whether its something you want to try?

i hadn’t heard anything bad about head and shoulders but then again, i don’t use it.

Sometimes a severe case is not dandruff at all but is psoriasis. If it is really bad I would suggest seeing a doctor. I have to continually use dandruff shampoo. I can never get rid of it completely. It’s a giant pain in the bum. There’s a good product called selsun I think. Its a strong one that may help you.

Hope you had some success with your dandruff problem?

I would also check out other natural sites. try the Tri nature website for items that maybe useful they have so many to be used on people and around the house. I use their clothes washpowder. My kids use to have skin issues due to what their clothes were washed in. Now they have no issues at all. I hope you find some thing that works…

let us know what works, I hope you find a solution soon.

Hub is the only person in the household who has dandruff and if I accidently use a dandruff shampoo by mistake , I get dandruff from it. He always buy Head and Shoulders shampoo and many times he buys the big bottle on special and next minute there are 3-4 bottles in the cupboard. He has been using this brand for a long time so try it as it may work for you .

My hair became worse using head and shoulders. I recommend shampoos free from Sulfate. Im yet to find a good shampoo and conditioner to combat it.

I had that same problem many years ago and started using shampoo and conditioner that are Free of sulphate and prarabens. Two chemicals that cause dandruff so now I use Sukin products.Look it up

Lush’s Soak and Float bar works well and is natural (and not very expensive).

Often the key can also lie within your diet. I.started to take fish oil capsules. For me this has really supressed my irriated scalp and dandruff. Good luck

I use a baking soda and water rinse after shampoo and conditioner which I find helps to relieve the itchiness. I also don’t wash my hair until it REALLY needs it or I am going out somewhere special (2 times a week on most weeks) i find that the more I strip my hair of its natural oils the more dandruff I get…

I also had issues with Head & Shoulders which is extremely disappointing considering they are advertised as a specific Dandruff shampoo!
Some great answers here & I would love to hear how you go!
I’m still trying to find something myself.