It is my HG shampoo! I've been using it for almost 6 months now and I absolutely love it. However, to be honest....for treating my dandruff, the only thing that relieves that is either living in Japan or in any Asian country for that matter (I live in Australia, but for some reason whenever I spend anytime in Japan, my dandruff goes away completely - perhaps it's the diet or the water....?), rubbing freshly squeezed lemon juice on my scalp(stings like hell but it absolutely works! Stops the flaking and itching for a couple of weeks, just make sure you don't leave it on for more than 30 mins and don't go out in the sun!) or shaving ALL of my hair off.
I actually bought the shampoo to treat hair breakage, and in that respect it's pretty great. That and changing how I apply shampoo and wash my hair reduced hair breakage in the shower by almost 80%. It's very gentle on hair, yet still effective at removing the oils, which some kinds of dandruff thrives on. So gentle that you don't need conditioner afterwards, it doesn't feel at all like it's stripped your hair and you don't get that squeaky hair feel like with a lot of shampoos. I use Damoae on alternative days to cleaning my hair with a silicone free conditioner.
It has a very herbal smell, so for people used to western shampoos it can be a bit weird, but I love it, it smells fresh and clean to me instead of cloyingly overly fragranced.
Basically, figure out what the cause of your dandruff is, mine I suspect is an over abundance of yeast in my scalp. I was blissfully dandruff free for about 4 years after I shaved my head, but then it came back with a vengeance after staying at my parents place, forgetting to bring my own products, using my parents Dove Conditioner to co wash instead and falling asleep with wet hair. The things that causes my dandruff absolutely love moist, non acidic conditions, coupled that with a scalp that over produces oil...and they're in heaven. I try to make sure my scalp is pretty much dry before I tie it up, and do a monthly lemon juice treatment.
When I have time, I'm going to see if I can test the pH of the shampoo, like the skin on your face, scalp needs a pH of 5.5 or less to be healthy.