Nasolabial Folds are the creases that form in the skin most often when smiling or laughing – which is why they are sometimes also known as ‘smile lines’. They appear at the sides of the nose and extend to the corners of the mouth. These lines appear naturally as part of the way we move our faces through expression. But a number of factors can lead to their accentuation and deepening that appear even when the face is at rest, such as, weight loss, genetic predisposition, ethnicity and the inevitability of the ageing process.