The Skinny on Topical Retinoids
Topical retinoids (Retin A, Renova, generic tretinoin)are the only prescription medications proven to reverse sun damage.
Tretinoin causes increased collagen production in the dermis, and it inhibits the enzymes that normally break down existing collagen in your skin. Those enzymes that break down your collagen are activated by UV radiation from the sun or other sources. Tretinoin also causes increased synthesis of elastin (the protein that makes up the elastic fibers in your skin) and it stimulates angiogenesis, the formation of new tiny blood vessels to bring more oxygen and nutrients to your skin cells every moment of your life. It decreases skin cell adhesion, making the upper layers of dead skin cells slough off more quickly, revealing smoother, fresher skin. Finally, it is responsible for thickening of the epidermis. Yes, that's correct. There is a pervasive myth that topical retinoids thin your skin, and they do thin the upper layer of dead skin cells (the stratum corneum), but they actually make all the other layers thicker. Because our skin becomes increasingly thinner with age, a medication that thickens the epidermis is a Very Good Thing.
More is better, up to the point at which your skin can tolerate the medication without too much redness or peeling. The original studies were done with low percentages (0.02%-0.05%), but there has been a study since then proving that 0.05% is better than 0.01%. So 0.1% (the highest available strength) is probably even better, although there has been no actual study to confirm this. Importantly though, the medication only works if you apply it regularly. So if you experience too much irritation with the higher strengths of tretinoin, it is better to use a lower prescription strength retinoid or even an over-the-counter professional strength retinol Every Single Night for years than to use the more irritating, higher strength creams sporadically.
You have to keep using it. Studies show that people who stop using the medication revert to the expected level of sun damage for their age within 1 year of stopping. Good stuff, these retinoids. What? You're not using one?? Do come talk to me and we will see which one is right for your skin.
Posted on Tue, October 30, 2012
by Heidi Gilchrist, MD