RXBAR PEANUT BUTTER 52G. Carrying a jar of peanut butter around can be inconvenient. So RXBAR made these peanut butter protein bars. These peanut butter bars are made with creamy peanuts, sea salt and a few other simple ingredients - egg whites for protein, dates to bind and nuts for texture. Satisfy the scoop (or three) of sweet and salty peanut butter you crave.