How to mix Azelaic Acid with Kirkland foam

[Dannyfire]

Hi i have just started the big 3, i have read on here that Azelaic Acid is a good DHT inhibitor.

Does anyone know in the UK where is best to by Azelaic acid from, and what percentage?

Ive seen some 20% stuff on amazon.

And also how to add it to my regime, do i put the cream on before using minoxidil or afterwards?

Many thanks.