by Dr. Charles Mok
In dermatology, we tend to think of skin as something that needs to be fixed. We focus many of our discussions on removing skin cancers, treating discolorations and blemishes, and even dealing with the effects of sun damage over the years.
But, what about prevention?
We are going to talk about the topical treatments (creams or lotions) that have the most robust scientific evidence behind them:
Numerous studies compiled over decades have shown that naturally occurring ultraviolet light from the sun is responsible for many undesirable skin conditions, most notably cancer. But discoloration, melasma, wrinkles, and poor skin tone are also the result of ultraviolet light. We are also learning that the ultraviolet light emitted by artificial light, although not as damaging as the sun, also leads to skin damage over time.
The Cause of Sun Damage
In April 2017, The New England Journal of Medicine published a study evaluating the cause of ultraviolet light-induced sun damage. In this study, they sought to determine what led to collagen degradation from the sun. (Collagen is a building block to skin, we make it all the time, and sun exposure is known to lead to more wrinkles, less elasticity to the skin, and other features associated with diminished collagen).
In the study they evaluated ultraviolet exposure and its effect on matrix metalloproteinases (MMP). MMP’s are enzymes that degrade proteins, one of which would be collagen. In this study, they found that ultraviolet exposure led to an increase presence of three MMP’s. One is called collagenase, which is an enzyme that breaks down collagen. There are two other enzymes: gelatinase and stromelysin. These three MMP’s are responsible for breaking down tissue. For the purpose of this article, I’m going to refer to collagenase, when talking about these MMP’s. Collagen is the building block to healthy skin. Therefore collagenase (and it’s cousin MMP’s) is the enemy to healthy skin.
In a New England Journal of Medicine study in 2017, they found that a single exposure to ultraviolet light led to increased production of collagenase, which of course damages collagen. The collagenase was increased in the skin as well as the connective tissue. In other words, the ultraviolet light not only affected the skin, but also the tissues supporting the skin. We can see this in aging, with direct effects on the skin, wrinkles, and discoloration. Damage to the connective tissue would lead to more sagging of the skin.
If the ultraviolet light was exposed repeatedly, this increase in collagen-damaging enzymes continued even after the ultraviolet light was removed.
The mechanism of skin aging from the sun, or other forms of ultraviolet light, is caused by the enzymes it stimulates in our skin and connective tissue to break down our skin and connective tissue.
What can be done to prevent damage from sun exposure?
Use Sunblock (Daily!)
Of the obvious answer is sunblock. Sunblock using a reflective ingredient turns ultraviolet light away from the skin and does, in fact, reduce sun damage. Even when you’re not exposed to the sun, we are exposed ultraviolet light from artificial lighting. In a previous blog, I talked about how effective sunblock alone was improving the appearance of skin.
A study done in Australia found that thousands of skin cancers could be prevented with the daily use of sunblock. As a culture, we tend to think of using sunblock when we are deliberately exposed to the sun. The studies have shown that daily use is the most practical means to reduce not only skin cancer but also improve the appearance of your skin.
While using sunblock is pretty obvious, you may not have thought about is using it every day (yes, every day) even when you’re mostly going to be indoors.
Studies evaluating the development of collagenase and other MMP’s in response ultraviolet light, compared the use of Vitamin A to placebo to measure the response sun damage. Vitamin A reduced the development of skin damaging collagenase by 70 to 80% compared to placebo. Vitamin A may have multiple mechanisms of action but is found specifically to prevent the development of damaging enzymes to our skin in supporting connective tissue.
Another study published in the Journal of Investigative Dermatology by the University of Michigan evaluated the use of Vitamin A in the form of retinol on photodamaged skin at various ages, from 18 to over 80 years old.
They found that age-related changes in skin were due to the increase of MMP’s, such as collagenase and other collagen-damaging enzymes. They decreased new collagen and decreased the number of fibroblasts, (specialized cells that produce collagen and other fibers for the skin and connective tissue). As people aged, those three factors were seen consistently. More collagen-damaging enzymes, less collagen, and reduce the number of specialized cells that build collagen.
In this study, they added Vitamin A (retinol) to the skin as a lotion daily. In as little as seven days, the treated areas had increased fibroblast cell growth (more cells that may contain collagen, the building block of our skin), there was more collagen production, and a decrease in collagen-destroying enzymes.
Vitamin A application can be a little irritating to some people. We recommend you start using it every other night a small amount and increase it to nightly use over a few weeks. Retinol is better tolerated better than other forms of vitamin A.
Vitamin C is a potent antioxidant. It is shown that ultraviolet light exposure to the skin leads to a depletion of Vitamin C levels on the skin. We think of taking Vitamin C orally (as a supplement), and then it goes everywhere in our body. This is true. However, ultraviolet light exposure leads to a local reduction of Vitamin C that remains in the skin. We’re going to talk about using topical Vitamin C as a lotion or cream.
Vitamin C regulates collagen production, so is an essential vitamin for the building blocks and maintenance of our skin. Vitamin C is also shown to reduce the redness associated with ultraviolet light exposure. In other words, it can reduce sunburns. When vitamin C is placed on the skin, it is absorbed by the deeper tissues as well, which would be beneficial to the skin support structure.
In a controlled study, Vitamin C was compared to placebo over six months for the treatment of sun damaged skin. In this study, Vitamin C was used daily as cream and compared to individuals who use a placebo cream. They found not only improvements in the skin’s appearance, wrinkles, color, but also found an improvement in the structure of the skin. This is important when considering managing sagging wrinkles. We have skin which can show sun damage. But the elasticity in the structure below the skin is what leads to deeper wrinkles and sagginess.
Glycolic acid is also known as an Alpha Hydroxy Acid (AHA). It is available in two forms. One form is a higher strength glycolic acid and is used as a chemical peel. Another form is a weaker strength of glycolic acid which can be used daily to reduce skin aging. Alpha hydroxy acids are naturally occurring acids that are found in foods, particularly in fruits. Glycolic acid works to increase the precursors to collagen in hyaluronic acid, both which are building blocks to the skin and connective tissue.
A study evaluated the use of glycolic daily moisturizer compared to placebo lotion. They were used twice daily for three months. They found that the use of glycolic acid moisturizer increased the skin’s genetic expression of cells to produce collagen in hyaluronic acid.
Another study measured the specific cells they were being activated by the use of glycolic acid. It is the dermal fibroblasts which are stimulated by the use of glycolic acid. The fiberglass makes collagen and other proteins that are necessary for healthy skin.
A study was conducted to address the use of glycolic acid after a sun burn. They found that the use of glycolic acid reduces the irritation that occurred after exposure to ultraviolet light. They then went on to treat skin with glycolic acid for three weeks before ultraviolet exposure. They found that the treated skin was less sensitive to sunburn, and it was equivalent of an SPF of 24. This is not a substitute for sun block. But, daily use of glycolic moisturizer, not only stimulants collagen formation, improves wrinkles texture and color of the skin, but it also protects against sunburn to some degree.
There was a study done to assess the clinical effects of glycolic acid on the skin. With aging and light exposure, the dermis of the skin tends to thin out, resulting in wrinkles, unevenness, and fine lines.
In this study, middle-aged women were placed on one of three lotions: glycolic acid, estrogen or placebo.
Both estrogen and glycolic acid increased skin thickness, restoring it to more youthful feel and appearance. But the glycolic was superior, resulting in a 27% increase in skin thickness over six months.
We recommend at the very minimum for skin cancer prevention and protection against photodamage and premature skin aging the use of a daily topical skincare regimen.
Glycolic acid moisturizer can be used once to twice a day, in the morning and at night. Vitamin C should be used every morning, as it is very protective. Sunblock should be used every morning whether or not you plan to be exposed to the sun. Vitamin A should be used every evening. It is better to use vitamin A at night because it is light-sensitive.
Dr. Charles Mok