When will the small fine hair growing from Minoxidil turn into real thick hair?

It may take several months if the fine hairs ever grow into thicker hair. In general, hair growth from topical minoxidil is fine.

Thanks for the question. It takes 6-9 months for you to see just how much minoxidil can help you. Some of these hairs you're seeing may thicken up but some might not. 

It may have different effect time but in general, after 3-4 months you will start to see the effects of Minoxidil.