Does Retin-A Thin the Skin?

A common question that is asked is "Does retin-A thin the skin?" The answer is: no, it does not thin the skin. The source of the confusion has to do with what it does. Retinoids such as retin-A, differin, and tazorac are derivatives of vitamin A and have multiple effects on the skin. They stimulate cell turnover in the very outer layer of the skin , removing the dead skin cells on the surface which give an uneven texture and a dull appearance and clog pores. For this reason they work well for anti-aging and acne. This is the very outer layer of the skin called the stratum corneum (which is part of the epidermis) and is approximately one hundredth of a millimeter in thickness. The other action of retinoids is deeper in the skin, where they stimulate the production of collagen which provides the structural stability to the skin. This increases the thickness of the deeper layer of the skin called the dermis (which is approximately a full millimeter in thickness), leading to improvements in fine lines, wrinkles, and laxity as well as reduction in pore sizes. Since it thins the very outer layer of skin but thickens the deeper layer of the skin which is one hundred times thicker than the very outer layer, the overall result is a thickening of the skin. Retinoids can cause irritation and starting on a low dose and using them on alternate nights reduces this irritation. They also increase the sensitivity to the sun, so broad spectrum sunscreen with SPF of at least 30 must be used every day. Retinoids do not work overnight and it is important to be patient and use them for a few months to see results. Be sure to take high quality before and after pictures to be able to notice the difference. Women who are pregnant or breast feeding should not use retinoids.