Opinion about brand name azelaic acid based so call DHT blokers

[rcom440]

Hi guys. I read that post about koroush DHT blocker which is basically azelaic acid based topical.
Do not waste your money on it just buy azelaic acid with Zinc Sulfate.
I bought big tube of azelaic acid with Zinc Sulfate cream for $11. It's 20% azelaic acid so its pretty high percentage.

I think it will last me a year or so.