I recently started sweating really bad over the last couple years (just turned 30). I try to stay hydrated and wear compressions boxer briefs and underarmor style shirt underneath my dogi top. Hell, last seminar I completely sweated through my gi....like completely.
I take it there be pretty ladies at your gym? Because otherwise, I can't imagine a reason to feel self-conscious about sweating when you're working your ass off. Everyone expects it. Everyone accepts it. We're all (hopefully all) going home to take a shower afterwards, why the **** would I care if I was covered in your sweat? Plus in no gi, excessive sweating is your best friend. Slippery escapes ftw.
Stay hydrated, buy a gi that breathes better, do whatever you want to do. But the real answer to your "sweating problem" is that sweating isn't a problem.
Bring a towel, towel off a lot.
That's what I do
When your swet drips in their eyes use that moment to STRIKE!!!
I also sweat like crazy. When I used to train at ISD in Poway my instructor was kinda grossed out by it. I sweat that much more than a regular person. He directed me to bring extra shirts and take breaks to change throughout the night.
1. Change your diet under medical supervision. Usually works wonders in that respect.
2. Also, invest in quality cologne with a strong perfume, usually a bottle of 40++ $. Everybody sweats. Not everybody needs to smell.
Haven't looked into this myself in any depth, but what seems to work for me has been losing flab, cutting salt and cutting spicy food.
So basically, make your life suck more.