A fellow co worker sent this article to me. Vitamin C is a hot topic of interest to skincare professionals. At the bottom of the article is IMAGE Skincare Hydrating ACE Serum.
When it comes to guarding the skin, we have sunscreen, an important weapon that can protect us from dark spots, wrinkles and skin cancer. But even though sunscreen is essential, it's not enough. Most of us typically apply less than one-quarter of the amount required to attain the specified SPF. Moreover, sunscreen washes off, not only by swimming and sweating, but also by imperceptible perspiration.
Where can we find additional protection?
The answer may lie in topical antioxidants. The skin naturally uses nutritional antioxidants to protect itself from photodamage. But the beneficial effects of these nutritional antioxidants are limited. This is not the case, however, with effectively formulated topical antioxidants.
Topical antioxidants can produce far higher concentrations in the skin than nutritional supplements. And once topical antioxidants are absorbed into the skin, they cannot be washed or rubbed off. Therefore, they protect the skin for several days, enhancing the power of sunscreens. Furthermore, applying topical antioxidants regularly can reverse previous photodamage.
But not all topical antioxidants are created equal. The formulation must keep the active antioxidant stable in an effectively high concentration in the molecular form so it can be absorbed and metabolized by the skin. Unfortunately, most commercial products don't meet these stringent standards.
Following is an analysis of topical antioxidants that provide benefits to the skin.
Vitamin C
Vitamin C (L-ascorbic acid) is our body's major antioxidant and is absolutely vital for life. All animals make their own vitamin C, with the exception of humans, primates, the Indian fruit-eating bat and the guinea pig. A 59 kg goat, for instance, synthesizes 13 g of vitamin C per day, almost 200 times the American Food and Drug Administration (FDA) recommended daily value.1 Not only do animals make hundreds of times the vitamin C we ingest, but they also can synthesize more than 10 times their normal amount of vitamin C when under stress.
Exposure to sunlight, pollution and cigarette smoke depletes the level of vitamin C in our skin. Topical application is the most effective way to significantly increase levels of vitamin C in the skin. In fact, applying 10 percent vitamin C increases the concentration to a factor of 27 times that of oral ingestion.2 Applying vitamin C daily for three days achieves optimal levels in the skin. Even if application is stopped, significant amounts of vitamin C remain in the skin for up to four days.3
To attain and optimize its percutaneous absorption and full activity, vitamin C must maintain its precise molecular form.4 Although L-ascorbic acid is an excellent antioxidant, it's inherently unstable. Most products contain stable derivatives that cannot be absorbed or metabolized by the skin (such as ascorbyl-6-palmitate or magnesium ascorbyl phosphate). Therefore, they have no activity.3 Other common formulations don't have the correct acidity (pH).
Vitamin C is an antioxidant that deactivates the damaging free radicals generated by UV. It is not a sunscreen. However, applying vitamin C before (and even after) sun exposure can greatly lessen redness and sunburn. This protection can be confirmed scientifically by examining skin in the microscope; the number of abnormal sunburn cells is decreased by 40 percent to 60 percent,2 and the UV damage to DNA is reduced by 62 percent.2
Vitamin C on the skin directly stimulates collagen synthesis, which is one of its main benefits. It's an essential cofactor to hydroxylate lysine and proline, which is required for collagen synthesis. Without vitamin C, we develop scurvy, with bleeding gums and nonhealing wounds.
Exciting experiments compared newborn with elderly (80- to 95-years old) fibroblasts, which synthesize collagen. Elderly cells proliferate in vitro more slowly and synthesize less collagen than newborn cells. However, when vitamin C is added to the culture medium, the elderly cells proliferate better than normal newborn fibroblasts, synthesizing more collagen. When given extra vitamin C, the newborn cells proliferate
almost four times faster, doubling the amount of synthesized collagen.5
Topical vitamin C also increases the synthesis of several specific skin surface lipids.6 Not only does vitamin C help moisturize the skin naturally, but it also enhances the protective barrier function of the skin.7
In addition to stimulating collagen and skin surface lipids, topical vitamin C can reverse the appearance of photoaging. In fact, it can decrease wrinkles, fade brown spots (or solar lentigos), and correct elastic tissue damage. Ten percent vitamin C is even more effective than most prescription bleaches in correcting the mottled pigmentation of sun damage.
Vitamin E
Vitamin E is our body's most important membrane-bound antioxidant that's delivered to the outer layer of the skin by sebum.8 As the body's outermost defense, the skin is the first to absorb the oxidative stress of sunlight and pollution. Vitamin E is depleted as it protects, so topical application is particularly important.
Several forms of vitamin E exist in our natural diet. The form of highest concentration in mammalian tissues has the greatest biologic activity--pure, nonesterified d-a-tocopherol. The other natural forms are b, g and d, which give only 42 percent, 72 percent and 40 percent, respectively, of the protection against UV achieved by the a isomer.9
The synthetic form is "dl," a mixture of eight stereoisomers (seven of which cannot be used by the body). The synthetic isomers are "esterified" (to acetates and succinates) for commercial vitamins and most topical formulations because these esters are far more stable. The ester forms must be broken down to the natural "-ol" form before any biologic activity occurs, a reaction that readily takes place in the stomach. But the benefits are slow to reach the skin. The skin can only minimally metabolize the esterified forms of vitamin E to the active free tocopherol form, so the antioxidant activity is minimal.10
Furthermore, the all-rac form of vitamin E, when applied to the skin, can cause allergic contact dermatitis11 and the severe blistering disease erythema multiforme.12 No such adverse reactions have been reported with natural d-a-tocopherol.
In contrast, creams or lotions with concentrations of 2 percent or more (5 percent is optimal) of natural vitamin E markedly decrease sunburn when applied regularly or just before sun exposure. They're less effective, but still helpful, when applied after exposure. In experiments with mice, natural vitamin E creams decreased the number of skin cancers caused by UV light.13
Like vitamin , vitamin E creams can reverse the appearance of photoaging by reducing mottled dark spots and decreasing wrinkles. Microscopic and electron microscopic examination of the skin corroborates these corrections. Vitamins in Combination
Water-soluble vitamin C is intracellular in r-elatively high concentrations, while vitamin E is membrane-bound. Thus, the plentiful vitamin C can regenerate the neighboring oxidized membrane vitamin E. 14
Although either vitamin alone is not effective, oral vitamin C with E in high doses protects against UV-induced sunburn in humans. 15 Topical L-ascorbic acid (15 percent) with a-tocoperol (1 percent) gives fourfold protection against UV-induced sunburn and DNA damage. 16 Each alone gives only one-half of that protection. Fortunately, mixing these hydrophilic and lipophilic antioxidants in a topical formulation stabilizes each and is cosmetically attractive.
Ferulic acid is a potent antioxidant that exists in cell walls of grains, fruits and -vegetables. Ferulic acid alone absorbs some UV and, therefore, is a weak sunscreen. When mixed with vitamin C and vitamin E, however, it stabilizes the formulation and acts synergistically to double the photoprotection from fourfold to eightfold. 17 This triple antioxidant combination has been made into the SkinCeuticals product C E Ferulic (with 15 percent vitamin C, 1 percent vitamin E, and 0.5 percent ferulic acid).
This combination is better than any of the vitamins alone in reversing photoaging.
Selenium
Selenium is an essential trace mineral in humans and animals. It's required by two important intracellular antioxidant enzymes-- glutathionine peroxidase and thioredoxin reductase. 18 Selenium also offers other benefits by directly protecting against DNA damage; inhibiting neoplastic transformation; and suppressing mutations, possibly by regulating the tumor suppressor protein p53. 19
As a mineral, selenium is unevenly distributed throughout the world. Many epidemiologic studies indicate that the incidence and number of deaths from cancer are higher in areas where selenium sources are low. 18
Some studies found that a higher blood concentration of selenium was associated with a reduced risk for several kinds of cancer. 18 A study of 240 nonmelanoma skin cancer patients in good general health demonstrated a significantly lower mean plasma selenium concentration than control subjects without skin cancer. 20 In fact, those patients whose blood concentrations were in the lower decile had 4.4 times the incidence of skin cancer as those in the highest decile. 20
In a 10-year prospective study of 1,312 patients with a history of basal cell or squamous cell carcinomas of the skin, selenium reduced the incidence of lung, colorectal and prostate cancer, as well as lung cancer mortality. However, selenium did not protect against further development of new skin cancers. 21
Selenium has been used for years in topical preparations as an antifungal agent. Shampoos (2 percent as over-the-counter preparations) and lotions containing selenium sulfide (2.5 percent by prescription) effectively treat Tinea versicolor, a common superficial fungal infection of the skin. Topical selenium sulfide is also effective in treating seborrheic dermatitis and dandruff. However, the selenium from these preparations is not absorbed by the skin, so the therapeutic effect is only on the outer layer.
Selenium can be absorbed transdermally when applied as selenomethionine (SeMet), which shows increased skin and liver levels of selenium after topical application. 22 In one study, a .02 percent formulation decreased sunburn in humans. 23 Further experiments with Skh:2 mice treated with SeMet cream showed decreased UV-induced damage to the surface skin, as well as deeper collagen and elastic tissue. It also decreased sunburn, post-UV tanning and skin cancers. 22
Topical L-selenomethionine also can effectively reverse and prevent photoaging. 24 Histologic and electron microscopic analysis confirmed that L-selenomethionine repaired surface skin thickening and irregularity. It also repaired deeper damage to collagen and elastic tissue. 24
Scientific research confirms that topical antioxidants can, indeed, offer exciting new possibilities. They can protect the skin from UV damage to retard photoaging. Moreover, they can reverse photodamage.
Think of topical antioxidant protection as "beauty in the bank." These topicals can reverse the appearance of aging, representing a kind of "interest" patients can happily accrue throughout life.
For a list of references, click on the references toolbar.
Karen E. Burke, MD, PhD, is on the faculty of the department of dermatology, Mt. Sinai Medical Center in New York. She has a private practice specializing in medical and cosmetic dermatology. She is a research scientist currently studying topical antioxidants. She is the author of four books, including Thin Thighs for Life, Great Skin for Life and Thin Thighs Diet and Workout. She frequently writes articles for medical journals and chapters for medical textbooks.
Disclosure: Dr. Burke formulates a topical d-a-tocopherol lotion and cream for her patients. She indicates that she has no affiliations with any commercial entities, directly or indirectly referenced in this article.
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