In our first post of this series, we explored the differences between Retin-A and retinol serum, and concluded that both have value. In short, if you want to delay skin aging, it’s a good idea to choose one or the other and use it religiously. Why? Because retinoids really work, and the results are impressive. With consistent use, you'll see visible improvements to the skin in the form of reduced wrinkles, diminished hyperpigmentation and better skin texture.
Now, we'll visit the some of the mechanics behind how vitamin A, aka retinol, manages to do the impossible—namely reverse photoaging damage.
How Retinoids Work
Retinoid usage, when it is long term, goes deep. The skin changes are profound, and are unrelated to deep cleansing, rehydrating or even reducing oxidative stress—the more common age-reversing measures.
Retinoids work at the cellular level by activating retinoic acid receptors in the skin. The jobs 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 as well as at the epidermal level. 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 the process, thereby reversing signs of photoaging, so skin actually appears younger. Retinoids accomplish this happy turn of events by binding to and activating retinoic acid receptors.
The induced changes include:
- Epidermal hyperproliferation (Epidermis sheds dead skin cells more readily, and replaces them with new, healthy cells.)
- Compact stratum corneum (the epidermal barrier)
- Expansion of intercellular spaces
- Increased deposition of GAGs (glycosamineglycans like hyaluronic acid) in epidermis
- Increased deposition of collagen in dermis
- Proportional decrease in epidermal melanin (due to increase in total cell volume)
Retinol vs. Retinoic Acid
Both retinoic acid and retinol cause changes in the skin, but changes produced by retinol occur without the irritation associated with retinoic acid. 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 now 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)
The Other Age-Retardant
Continued use of retinoids is one way to keep your skin functioning at its best, pretty much permanently. The other topical genuine age-retardant? Well, everyone agrees on this one—wear sunscreen rain or shine, every day, and for good measure, make sure it contains excellent UVA protection, such as, for example, zinc oxide. UVA rays, the longer wavelength rays, are the aging rays (think "A= aging"). They are present sun up to sundown, and pass through clouds and glass. Thus, the reason we encourage everyone to wear sunscreen every day, even if it’s raining—even if you are inside and it’s raining.