how well does toppik hold up with sweat. i dont mean like playin sports but just if it was hot and you were sweatin or had to walk a lot in the heat. and also does wearin a hat mess toppik up at all?

For me, it holds up fairly well on my diffuse, thinning crown and mid-scalp. A little perspiration or hat wear does not seem to adversely affect its camouflaging properties.

As far as my really bald areas (high temples), I do not have the same luck using Toppix with what little native combover hair that I have left. The binding properties are short-lived.

In general (for me), Toppix is more resilient to hat & heat when used to hit the scalp directly, thus reducing the contrast between hair & scalp.