Smoking accelerates the normal aging process of skin, contributing to wrinkles and fine lines, droops, sag, dryness, coarseness, and uneven texture. Long term smoking will cause premature skin aging for only 10 years of smoking, although the early effect of smoking on the skin is not visible. The adverse effect of smoking on skin is not limited to facial appearance, skin on other parts of the body are also affected. Smoking not only speed up skin aging process, but is also associated with delayed wound healing and is the cause for other unfavorable skin conditions. These include: skin cancer, psoriasis, hidradenitis suppurativa (acne inversa), skin vascular disease, cutaneous lupus erythematosus, viral infections of the skin. There is some evidence indicate that female’s skin appears to be more affected by smoking than that of male.

One effect of smoking on the skin is through the action of nicotine on blood vessels in epidermis. Nicotine causes narrowing of the micro blood vessel in the outermost layer of skin (epidermis) – an effect known as vasoconstriction. It impairs and blocks blood vessel from bringing oxygen and nutrients to epidermis, resulting in deficiency in crucial nutrients (e.g. antioxidant vitamins) and energy metabolism for the health of skin. Carbon monoxide also displaces oxygen for binding to hemoglobin, causing deficiency in oxygen supply in the skin.

The damaging effect of chemicals (there are about 4000 chemicals in the smoke) on skin structural protein fibers (collagen and elastin) have been revealed from several studies. Collagen and elastin are important structural protein in the dermis of skin – they form complex network of fibers (part of the skin extracellular matrix) which give skin its strength and elasticity. Damage of collagen and elastin fiber system (elastosis) is the major reason of wrinkles and sag formation, especially when dehydration is also a problem.  Morphometric and Immunohistochemical analysis of the skin from smokers (http://www.ncbi.nlm.nih.gov/pubmed/17199572) suggest the occurrence of elastosis (increased degradation of elastic fibers) – a process also occur during photo skin aging (sun exposure). In vitro studies found that tobacco smoke extract impairs the synthesis of collagen and increases the production of tropoelastin and matrix metalloproteinases (MMP) by dermis fibroblast and also causes an abnormal production of elastosis material. MMP is the extracellular matrix proteinase which degrade matrix proteins (collagen and elastin). When not in excess, MMP removes degraded collagen and elastin fragment from the extracellular matrix, allowing the newly synthesized collagen and elastin to replace the degraded fragments. However, excess MMP damages collagen and elastin fiber systems. How elastosis contribute to the formation of wrinkle? – see post “The Elastic System of Skin” and  post “What exactly constitute a wrinkle?”. For the role of MMP in skin aging, see post “Matrix Metalloproteinase (MMPs) and MMP inhibitors in wrinkle creams”.

In addition, heat from burning cigarettes can cause the repeated facial muscle movement which in turn cause wrinkles (facial expression lines). These can be the repeated lip movement while inhaling and exhaling and the repeated eye squinting to keep out smoke. How facial muscle movement can cause expression lines? – see post “facial wrinkle lines and anatomy of facial muscles.