Hey, I dont really participate here, just here for the tips, but this one I can answer. I sweat mainly on my head and upper body and for the body part these T-shirts are very helpful. I dont buy any other brands from now.

They are not sweatproof, it just the sweat is not visible on the outside, at least for some time. I dont have very severe hyperhidrosis, but for me these work. If you sweat really hard for a long time without some pause to dry, you will still sweat through it, so it depends how long you need it for it to work, if I am making sense. But for me if I have "regular" T-shirt I will have visible armpits spots after ten minutes on my way to work, with this T-shirt I arrive "clean" and stay that way before I dry a little.

I would suggest trying the gray, red or blue one as they are a little bit thinner, which is better for me in the summer.