What Is Oxidative Stress & What Does It Do To Skin? Our Deep Dive

Once upon a time, skin care was all about topical products like masks and toners. But as research digs deeper into the link between internal and external health, it's becoming clear that successful skin care is rooted in cellular beauty.*

Oxidative stress starts with molecules called free radicals1. They’re created as normal byproducts of cell metabolism or by exposure to external sources like X-rays, air pollution, cigarette smoking, and pesticides. Free radicals have an uneven number of electrons, which poses a problem—because electrons "like" to be in pairs. This means free radicals will steal electrons from healthy molecules to stabilize themselves. Oh, and guess what happens to that molecule? It turns into a free radical, and the chain reaction continues. 

Our bodies have natural ways of keeping free radicals in check, though. Plus, free radicals aren't necessarily malicious. In low to moderate amounts, they can lend a hand. For instance, white blood cells called phagocytes make and store free radicals2. If unwelcome invaders come around, the phagocytes can come to our defense by unleashing free radicals. 

A prolonged state of oxidative stress speeds up the skin aging process4. Specifically, it contributes to the loss of collagen and elastin fibers, resulting in fine wrinkles, sagging, and texture changes. It can also trigger dark spots and other discoloration. But it's not just about these "signs of aging"—oxidative stress affects skin's basic functions: Oxidative stress is also involved in reduced barrier function, increased sensitivity, and decreased moisture.

Antioxidants are molecules that stabilize free radicals by donating an electron. This is important because antioxidants don't turn into free radicals after giving away an electron. Or, they might make free radicals harmless by breaking them down. That's why it's crucial to consume an antioxidant-rich diet, says Michele Green, M.D., cosmetic dermatologist. "Antioxidants protect the inner and outer skin from free radicals," she explains. "They [also] provide protection from the sun and aid in cellular repair." 

Antioxidant-rich foods can be summed up in one word: plants. Lots of 'em. See, plants have antioxidants5 to protect themselves from oxidative stress, a perk you can also enjoy by eating a plant-based diet full of fruits, vegetables, herbs, nuts, and whole grains. (For what it's worth—your body also produces antioxidants on it's own, too. But consuming additional varieties helps your body function properly.)

Since cutaneous oxidative stress9 contributes to irritated, sensitive, dry and dull skin, it's also best to use antioxidants topically. Why not address it holistically, no? "Skin care products with antioxidants are essential to overall skin health," says Green. She recommends focusing on nutrients like niacinamide, glutathione, and vitamins A, C, and E. 

If you're a skin care fanatic, you probably saw this coming. External aging, after all, is primarily fueled by UV radiation4—and the oxidative stress that comes with it. Hilsabeck compares this effect on your skin to a bull in a china shop. "UV radiation comes in, knocking electrons around and creating negative chain reactions," he says. This depletes your antioxidant stores, adds Cheung, which can result in leathery, wrinkled skin. 

Psychological stress doesn't just harm your heart and mind—it also promotes oxidative stress in the skin. If this persists, it can overpower the skin's antioxidant defenses, leading to signs of aging. This is why mental health and mindful practices are an essential part of skin care.

There's a reason the term "beauty sleep" exists. According to Green, inadequate sleep prevents the skin from properly repairing itself. It also causes oxidative stress10, she says, leaving the skin looking sallow. Other side effects include wrinkles, pigmentation changes, and other signs of aging.