Does it help to work out in a sauna suit?

You’ll lose more weight, but it will be in the form of sweat. Boxers do this to get down to a certain weight before a fight.

It’s not very healthy as it takes more water from your body than you’d lose without it. To keep from becoming dehydrated (and believe me, people regularly die from dehydration), you would need to drink lots and lots of water, which would negate any weight loss you might experience from donning the suit.

I’d steer clear.