Antioxidative enzymes and molecules occur naturally in the body, where they defend cells against oxidation. But as we age, these enzymes become less active leading to an increased risk of cellular damage. It’s no surprise, therefore, that topical antioxidants have become key ingredients in antiaging skincare products, where they protect the skin from damaging UV exposure and environmental pollution. But the benefits of antioxidants stretch beyond preventing the signs of aging. More recent evidence shows that topical antioxidants can help reduce the redness of sunburn and even ease the inflammation of rosacea.
“Oxidation happens when oxygen atoms combine with other atoms, and sometimes the oxides that are produced in these reactions are toxic—they can interfere with the activity of cells,” explains John Kulesza, president of skincare company Young Pharmaceuticals. “Antioxidants, in general, are compounds that prevent oxidation reactions.”
Antioxidants and Aging
In her latest textbook Cosmeceuticals and Cosmetic Ingredients (McGraw Hill 2014), dermatologist Leslie Baumann, MD, identifies a number of antioxidative enzymes and molecules that are naturally produced by our bodies, including superoxide dismutase, catalase and ascorbic acid (vitamin C). The problem is that these defense mechanisms become less active as the body ages. “This leads to an imbalance and increased number of unchecked free radicals, which engender damage to DNA, cytoskeletal elements, cellular proteins, and cellular membranes,”she writes.
While minimizing free radicals is thought to prevent wrinkles (rather than treat those already present), Dr. Baumann notes that topical antioxidants have other antiaging benefits as well. “In addition to the effects associated with their antioxidative activity, many antioxidants exhibit anti-inflammatory properties or depigmenting activities,” she writes. “They protect cell membranes, proteins, DNA and mitochondria.”
In particular, antioxidants protect the skin cells against damaging UV exposure and environmental pollution. “They are the hero ingredients when it comes to defending the skin from environmental damage,” says Sarah Longton Pajaro, executive director of accounts and education for LIFTLAB Skin Regeneration. “UV radiation causes the formation of free radicals, which break down collagen and rearrange elastin. This leads to deterioration in skin’s structure and strength. When antioxidants are present, they are able to catch and neutralize these scavengers to prevent damage.”
More Effective Sun Protection
In recent years, antioxidants have become common ingredients in sun protection products. “Sunlight, especially ultraviolet light, has a lot of energy that is able to knock electrons off of atoms, creating reactive oxygen species—which can be damaging and lead to inflammation,” says Kulesza. “There are classic studies that show if you apply an antioxidant, like vitamin C, to the skin immediately after sun exposure, you can reduce the amount of redness that occurs.”
He adds that there is a window of time within which an antioxidant may be applied in order to have the desired effect—if you wait too long after sun exposure to apply the topical antioxidant, it won’t work.
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Adding antioxidants to sun protection products may address this issue, because it minimizes the amount of reactive oxygen species that are formed during exposure while preventing sunburn at the same time. “When you layer antioxidants with a broad-spectrum UVA/UVB sunscreen, they work as partners,” says Pajaro. “The antioxidants fight and prevent free radical damage inside the skin, while sunscreen absorbs or reflects harmful UV rays to help prevent burning and sun damage on the skin’s surface.”
Since no SPF is perfect, topical antioxidants in sun protection products will also help defend skin from any radiation that gets through the sunscreen, adds Dr. Baumann.
Research on the most effective combinations of antioxidants and sunscreen ingredients is still ongoing. “What we don’t understand is how the antioxidants work with different degrees of SPF,” says Jeannette Graf, MD, assistant clinical professor of dermatology at Mount Sinai Medical Center in New York City. “In other words, do you need a higher level of antioxidants if you’re making an SPF 15 versus 50? That’s an important question that’s being investigated even now.”
Functioning Formulations
The main formulation challenge when it comes to antioxidants involves the very air we breathe—once antioxidants are exposed to the atmosphere, they start reacting to oxygen. “For example, we can dissolve vitamin C in a solution, but these solutions eventually oxidize—they react with oxygen in the air, turn brown and lose their potency,” says Kulesza. “It’s the same challenge with green tea, which is a popular, very powerful antioxidant. Ferulic acid, a fascinating antioxidant material, also reacts with oxygen in the air.”
Additionally, antioxidants will react with the oxygen in a water-based solution. “Keep in mind that water is H2O, and antioxidants dissolved in aqueous media will react to it even without exposure to air,” he says.
Formulators have found a way around these challenges through the use of airless pumps and packaging that protect the ingredients from oxidizing, and by substituting other solvents—such as glycerin, propylene glycol and other polyhydric alcohols like ethoxydiglycol—in place of water to improve the antioxidants’ stability. Pajaro even suggests opaque packaging to keep actives from deteriorating due to light exposure.
Another way to overcome these formulation challenges is with “the use of stabilizers—antioxidants that protect antioxidants,” says Kulesza. “One reason it’s beneficial to combine ferulic acid with vitamin C is that the ferulic acid protects the vitamin C from oxidation. So it has a stabilizing effect on the formula.”
Combining multiple antioxidants in one formulation can also increase their efficacy. “In ß-keratin studies, when they looked at ß-keratin separately from lycopene and lutein, lycopene had the highest protection. When they combined all three, the combination offered much higher protection than lycopene alone. So I’ve always felt that more is better,” says Dr. Graf.
Once the antioxidants have been stabilized, the next challenge is to improve skin penetration. “It’s really about the encapsulation of antioxidants now, because that’s one of the ways that we can improve stability and delivery,” says Dr. Graf.
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On the Horizon
With research on topical antioxidants ongoing, we can expect to see some new ingredients in addition to old favorites. Kulesza predicts that there will be more work with ferulic acid esters. “An ester is simply where we attach a fat to the ferulic acid, and that can actually improve the stability of ferulic acid,” he says.
Formulators are also turning toward resveratrol over green tea because it poses less of a challenge in terms of penetration. “Resveratrol and green tea are phenolic compounds, which means they have a ring of six carbon atoms—phenolic compounds in general are powerful antioxidants,” says Kulesza. “But green tea is a very large molecule, and there are challenges in terms of its size, stability and its ability to penetrate in the skin. Resveratrol actually is a much smaller molecule and it may also have some skin lightening or brightening capabilities. So we may be seeing more products using resveratrol as an antioxidant.”
LIFTLAB’s focus is on its proprietary Cell Protection Proteins (CPP), which stimulate the formation and production of antioxidant proteins as well as collagen and elastin. “CPP paired with topical antioxidants is a dynamic combination for treating the skin against the aggressors of aging,” says Pajaro. “They work as a team to offer immediate and long-term free radical control.”
Another antioxidant ingredient currently in development is ephemer, though it has not yet been listed with the International Nomenclature of Cosmetic Ingredients (INCI). Ephemer is extracted from microalgae grown in a laboratory environment in seaweed. “There is a particular growth stage in which the microalgae cells accumulate an abundance of antioxidant molecules, so researchers are trying to extract this particular group of cells,” says Dr. Graf. “What they’ve found in early experiments is that the extract protects the skin for up to 24 hours after application by acting on the mitochondria.”
Oral and topical argan oil sourced from Morocco works well with dry and sensitive skin, says Dr. Baumann. “It has hydrating, anti-inflammatory and antioxidant properties, plus it’s high in linoleic acid, which helps your body make ceramides to hydrate and decrease inflammation,” she says. She notes in her book that argan oil has a heavy texture and is expensive, but there is anecdotal evidence that it may also help soothe rosacea.
“Of course ascorbic acid, green tea and resveratrol are also great—not new—but have great data,” Dr. Baumann adds. “My rule of thumb is to eat, drink and put on topically as many different kinds of antioxidants as you can.”
Laura Beliz is the associate editor of MedEsthetics.
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