Vitamins like B1 (thiamine), B2 (riboflavin) and B6 are some of the best things for keeping your lips soft and smooth. Dry lips can be due to a lack of these vitamins, so you could try squeezing more of them into your diet. Beef, milk, nuts and oats are good sources of B1, while green vegetables, meat, fish and dairy contain B2. You’ll find B6 in pork, chicken, fish and wholegrain cereals.