Etiologically, upper lip lines come from several underlying factors that affect the area;
Sun exposure – the upper lip is often one of the areas that is significantly affected by the sun, or more specifically, UV radiation. Chronic sun exposure causes oxidative damage to the skin, leading to wrinkling as well as other skin concerns such as skin cancers and pigmentation problems.
Loss of volume – possibly one of the less obvious causes of upper lip wrinkling. Loss of subcutaneous fat in particular can cause the upper lips to shrivel, and as a result cause wrinkles.
Muscle contraction – the muscle surrounding the mouth, orbicularis oris, is responsible for closing the mouth and is activated during speech. Pursing the lips can crease vertical lines into the upper lip.
Smoking – although upper lip lines occur in both smokers and non-smokers, smokers purse their lips more frequently and this increase wrinkling around the mouth. Toxins from cigarettes can also accelerate the ageing process of the skin in general.
One of the causes of wrinkling of the upper lip is volume loss.