Retinoids are an ingredient we will always recommend for the simple fact that they really work, and the results are impressive. With consistent and long-term use, retinoids go deep, yielding visible improvements to the skin in the form of reduced wrinkles, diminished hyperpigmentation and better skin texture. The skin changes are profound, and are unrelated to deep cleansing, rehydrating or even reducing oxidative stress—other common age-reversing measures.
In youthful skin, the epidermis is thin, and the dermis is thick. As we age, we start to see this reverse itself; dead skin cell buildup leads to a thicker epidermis, while at the same time the dermis is thinning. Retinoids invert this process, reversing signs of photoaging, so skin actually appears younger. They accomplish this on the cellular level binding to and activating retinoic acid receptors in the skin. The jobs that those receptors do vary: some initiate collagen production, others normalize cell turnover rate. They also inhibit the activity of other transcription factors like AP-1, which plays a role in inflammation. Basically, retinoids improve the way skin sheds and renews itself at the dermal and epidermal levels.
The induced changes include:
Both retinoic acid and retinol cause changes in the skin, but changes produced by retinol occur without the irritation associated with retinoic acid. (More on that, here.) Retinol, in fact, is generally considered a prohormone of retinoic acid. The mechanisms that induce the profound changes in skin listed above are “mediated by tightly regulated conversion [of retinol] to retinoic acid.” (Kang, et al., 1995). For this reason, some researchers suggest that topical applications of retinol, rather than retinoic acid, may be a more efficient and natural way to deliver retinol to “the correct subcellular location within skin cells…” (Fisher, et al., 1996)
Continued use of retinoids is one way to keep your skin functioning at its best. The other topical age-retardant that actually works? Sunscreen—worn every day, rain or shine. For good measure, make sure it contains excellent UVA protection, such as, for example, zinc oxide. Think of UVA rays, the longer wavelength rays, as the aging rays ("A= aging"). They are present sun up to sun down and penetrate through clouds and glass, so it’s essential to wear sunscreen daily, regardless of conditions.