Shampoo for dandruff

It is a shampoo named Head & Shoulders Clinical Strength.

To my knowledge, it is not available domestically and can only be purchased through overseas direct shipping. I suppose it is due to the ingredients. It is quite a well-known product among those with dandruff or scalp inflammation.

I don't know why, but I get dandruff occasionally, regardless of whether it's summer or winter. Whenever that happens, using this shampoo improves noticeably. Aside from the scent being a bit unpleasant... it smells like medicine, I guess you could call it. I'm worried about the ingredients, so I tend to use it only for a short period when I get dandruff, rather than every day.