They work in different ways.Why choose.I use them both in the same product.
Not so sure about humectancy and those two, since urea is generally used as a keratolytic. Place a 40% urea solution on your nail plate and overnight the nail will have dissolved and you'll be ready for toe surgery. Reason for using sodium lactate-lactic acid with high urea content is that is the best buffering system to stabilize urea at pH 5.0 - 5.5. Urea decomposes (reduces) into ammonia in aqueous solution - just ask any farmer who uses it for fertilizer.
It looks like you're new here. If you want to get involved, click one of these buttons!