Walk into any naturals store, and skin creams fortified with botanicals and vitamins abound. Known as cosmeceuticals, these products have a metabolic or chemical effect on the skin but are not classified as nutritional supplements by the U.S. Food and Drug Administration. They can make the cash register ring with high-margin sales, but retailers may wonder if there is any credible science to back up manufacturer claims of ?diminished crow?s-feet? and ?firmer skin? for these products. The answer, in many cases, is yes. Although many of the studies are preliminary, they do show promise for the burgeoning group of vitamins and botanicals being used in skin care products.
The bulk of cosmeceuticals are topically applied and are formulated with vitamins and botanicals that function as antioxidants, combating free radicals. Free radicals can weaken and destroy cells, making the skin more susceptible to wrinkles, age spots and cancer. Other botanical and vitamin ingredients work to promote collagen production and other key compounds essential to skin health. Still others work to reduce inflammation and irritation.
Following is a look at some popular cosmetic ingredients along with some of the science that supports their use in skin care.
First isolated in the 1950s, ALA?s role in protecting mitochondria and DNA material has been substantiated by many scientific studies. It is sometimes used to treat age-related diseases such as Alzheimer?s and Parkinson?s; however, research supporting long-term efficacy is not conclusive. Recognized as a powerful antioxidant in 1988, ALA also was found to potentiate the activity of other antioxidants, making them more available and effective. ALA distinguishes itself from other antioxidants, such as vitamins C and E, because it is both water and fat soluble, meaning it can function as an antioxidant in different environments. For example, it can penetrate fatty skin cell membranes and continue to work inside a cell?s watery environment.1
Although produced in small amounts by the body to perform basic functions, it must be supplemented for its potent antioxidant effects. As popular as the ingredient may be—due largely to Nicholas Perricone?s best-selling book The Wrinkle Cure (Warner Books, 2001)—more research is necessary to confirm its effectiveness for topical skin care.
In a randomized, placebo-controlled, double-blind study, researchers did find that topically applied ALA reduced signs of aging in skin. Thirty-three women, with a mean age of 54 years, applied a cream containing 5 percent ALA to one side of their faces for 12 weeks. Compared with placebo, the change was statistically significant but did not amount to a huge difference. At the end of 12 weeks, laser profilometry showed a decrease in skin roughness compared with the untreated skin. Photographic, clinical and self-evaluations also showed improvement in the ALA-treated skin.2
Results of an in vivo study showed ALA protected skin cells from sun damage and inflammation. Researchers discovered that low levels of ALA protected skin cells from acute ultraviolet radiation.3
Researchers have also studied ALA to measure its ability to penetrate the epidermis and protect susceptible cells from damage. In this study, ALA was applied to dead mouse skin to measure absorption rates. ALA quickly penetrated the skin, achieving maximum saturation in two hours.4 In addition, ALA has been shown to turn off an inflammatory messenger known as nuclear factor kappa B. In vivo, low levels of ALA were shown to inhibit NFkB activation, which can induce inflammation. These results indicate ALA may modulate cellular response to UV radiation. 5
Not all of the preliminary research has generated positive results. Topically applied ALA did not perform well in a study testing its antioxidant abilities for protection from sun exposure. When researchers at Duke University applied a formulation containing 5 percent ALA to pigskin for four days and then exposed the skin to ultraviolet rays, they observed no or very little photoprotection.6
Dimethylaminoethanol was also made popular by its mention in Perricone?s The Wrinkle Cure for its ability to improve skin health and appearance. Found in fish and made in small amounts in the brain, DMAE has been used as a supplement to enhance mental and physical performance for attention deficit hyperactivity disorder and Alzheimer?s disease. It is believed to increase the neurotransmitter acetylcholine, which is related to brain function. DMAE is also an established free radical scavenger.7
Although little research has been done to test DMAE?s ability to benefit the skin, the first randomized, controlled, double-blind human study did produce positive results. Shear wave propagation measured increased skin firmness after 30 subjects applied a 3 percent DMAE cream to facial skin.8
In another study, a 3 percent DMAE gel applied for 16 weeks to the faces of 156 adults with moderate sun damage resulted in firmer skin in the eye, lip and cheek areas.9 More research is clearly needed before DMAE can be considered a proven skin-firming agent.
Green tea (Camellia sinensis)
Green tea?s active constituent, epigallocatechin gallate, is a popular skin care ingredient for its proven anti-inflammatory, sunscreen and antioxidant capabilities.
In one study, researchers found that green tea reduced inflammation and protected skin from ultraviolet ray?induced oxidative stress. When researchers had human subjects topically apply 3 mg of EGCG to skin before UVB radiation exposure, they discovered several things. Lower levels of prostaglandin metabolites were generated (these metabolites play a critical role in free radical generation and skin cancer development), sunburn was decreased and the treated skin contained fewer dead skin cells.10
In another green tea study, findings surprised even the researchers. When comparing the growth rate of skin cells exposed to EGCG with that of unexposed cells, scientists found that EGCG actually reactivated dying skin cells. For about 10 days skin cells usually sit on the upper layer of skin before they die, but the EGCG reactivated them, causing cell division. The researchers are not yet sure how this may benefit the skin, but they believe it could result in treatments for wrinkles and some skin conditions, including psoriasis.11
Green tea may also be beneficial for treating acne. When 54 subjects applied a 3 percent green tea extract cream twice daily for 12 weeks, dermatologists found an overall improvement in the appearance of the subjects? complexion compared with the group that applied a 4 percent benzoyl peroxide cream, the most popular acne treatment. The subjects who used the green tea extract cream also reported fewer negative side effects, such as flaky, dry skin.12
Proven to fight heart disease, build healthy bones and offer mild estrogenic effects to mitigate menopausal symptoms,13,14,15,16 the isoflavones found in soybeans also may benefit the skin. Researchers are studying the potent antioxidant effects of the isoflavones genistein and daidzein for their ability to protect and heal skin from sun damage and aging.
In one study, researchers applied genistein and daidzein to both human skin cells and mouse skin. The isoflavone application increased the density and intensity of hyaluronic acid both in vitro and in vivo.17 Hyaluronic acid is present in connective tissue and cushions and lubricates the skin.
In another study, the topically applied soy protein lunasin prevented skin cancer in mice. Varying doses of lunasin were applied to groups of mice for 19 weeks. After the mice were exposed to chemical carcinogens, the group that had received the highest lunasin dose—125 mcg twice weekly—had a 70 percent lower incidence of tumors than the control group. The researchers compared lunasin to a watchdog; it appears to attack when it sees a cell undergoing abnormal transformation.18
A well-known and respected antioxidant, ascorbic acid has also been shown to help the body produce collagen, a protein that binds cells together and is critical to the formation and ongoing health of the skin. Because the human body does not manufacture vitamin C, it must be obtained through diet or supplementation. In one study, researchers found that postmenopausal women with the lowest dietary intake of vitamin C had the highest collagen production when ascorbic acid was applied topically to their faces. This indicates individuals deficient in vitamin C may derive skin benefits from topical ascorbic acid applications.19
In a recent double-blind, randomized trial, researchers found that topically applied vitamin C may be an effective treatment for aging skin. Healthy female volunteers with photoaged skin (showing wrinkles and lines) applied a cream containing 5 percent vitamin C for six months. Researchers performed clinical assessments at three and six months. The subjects who applied the vitamin C cream had decreased skin density and deep brow furrows as seen via biopsy and structural evidence.20
St. John?s wort (Hypericum perforatum)
Known for its ability to treat mild to moderate depression,21 this botanical is also demonstrating potential as an effective skin care ingredient. It has been used traditionally to treat burns and other skin irritations, and recent research may confirm these applications. St. John?s wort has many active components, including hypericin and pseudohypericin, flavonoids and tannins. Researchers currently regard hyperforin as the compound of primary benefit to the skin.22
In a half-side comparison study, 21 patients suffering from mild dermatitis applied a cream containing an extract standardized to 1.5 percent St. John?s wort to half their faces twice daily for four weeks. During the study, patients had three separate clinical evaluations. At each visit, the hypericum cream was found to be significantly superior to a placebo cream in treating the dermatitis, results that demonstrate therapeutic potential for St. John?s wort.23
In the same study, St. John?s wort was shown in vivo and in vitro to protect against sun damage, including inflammation and skin infection.
Also known as ubiquinone, Co-Q10 is a naturally occurring vitaminlike compound that plays a role in cellular energy production. Although the body produces Co-Q10, after age 35 or 40 production rates drop resulting in insufficiencies that can impair optimal function. Often used to treat heart disease, Co-Q10?s antioxidant abilities are what prompted researchers to test its efficacy as a skin care ingredient.24,25
In one study, Co-Q10 decreased the effects of skin tissue damage by lessening the effects of free radical molecules. In this placebo-controlled study, researchers found that after applying Co-Q10 daily to crow?s feet for six weeks, wrinkle depth was reduced by 27 percent; after 10 weeks, wrinkle depth was reduced by 43 percent. In the same study, researchers discovered the skin?s resistance to UV damage can be increased when CO-Q10 is applied.26
Results of several studies also have shown that when topically applied to rat skin, Co-Q10 is readily absorbed.27,28 This is important, because although many compounds perform well in vitro, they must also be able to penetrate the skin to work.
Although much of the research is preliminary, numerous botanicals and vitamins appear to have potential to benefit the skin?s health and appearance. Many consumers, though, are confused when they see ingredients such as soy, green tea and vitamin C in skin care products. But if responsible retailers take the time to educate themselves about new ingredients, they can help customers better understand what they?re buying.
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