These are great for posture. However! they squish your underarm & back fat up in an unflattering manner. Also, they squish your booty & lower abdomen down too. Basically they make you overflow the top and underflow (bulge) in the lower abdomen area. *gasp* It does flatten the upper abs so just wear something that doesn't show unflattering bulges
I thought it would be uncomfortable to work out in, but it was not. Definitely not comfortable for all day wear. I wear a light tank top underneath or it sticks to you and feels gross.  Definitely air dry after using or it's gets a really funky smell. I'd soak it in a light laundry detergent or warm water with vinegar (gets funky sweat and gym smells out) every few uses.