Why do tea, coffee and diet cordial dry my lips?

I drink plenty of water too...Why do tea, coffee and diet cordial dry my lips?
Maybe because you are not eating as much when you drink these things? We need to consume enough oils to keep our skin from drying out. The less I eat, the dryer my skin gets, even when I drink plenty of water. Even when I am drinkin caffeine free beverages, but I am not as hungry when I drink tea and coffee. Also everyone processes salt and water differently, some people are dehydrated by caffenated beverages and others are not. If our bodies do not retain as much salt then they also don't retain as much water, and sometimes, people who don't eat much don't get enough salt in their diets. It also depends on how often you drink caffeine, someone that drinks it seldom is more likely to be dehydrated from it b/c your body isn't used to it yet.