If you’ve spent any time exploring the skincare scene on TikTok, you’ll know that dermatologists love to touting the benefits of vitamin C serums and creams.
They claim that vitamin C can firm and brighten skin, protect it from sun and environmental damage, diminish dark spots and even fade the signs of aging.
“All of its benefits make it one of the top recommendations offered by most dermatologists,” said Fatima Fahs, a dermatologist in Michigan.
But it is not the same if we delve deeper into the research on the real effects that vitamin C has on the skin.
For example, in a 2021 review published in The Journal of Cosmetic Dermatology, Fahs and colleagues evaluated the efficacy of various vitamin C formulations in improving skin health and concluded that while some formulations appeared to have skin benefits, overall results were mixed.
The problem is that while vitamin C may be good for your skin, it’s not easy to make a product that works the way it’s supposed to.
How Vitamin C Works… In Theory
Research suggests that when vitamin C penetrates the skin, it protects and improves it in a number of ways.
It’s an antioxidant, so it’s able to neutralize harmful molecules called free radicals, which “accelerate the signs of aging,” said Whitney Bowe, a dermatologist in New York City.
Vitamin C can also stimulate the skin’s production of collagen, which is a protein that increases the firmness and elasticity of the skin and helps keep it hydrated and plump. Because of this, “consistently using a stable, potent vitamin C serum over time can help soften the appearance of fine lines and wrinkles,” Bowe explained.
Finally, according to Bowe, vitamin C can lighten dark spots because it inhibits an enzyme called tyrosinase that causes skin discoloration. Although there has been little research on the effectiveness of vitamin C for this purpose, a small study published in 1996 found that vitamin C reduced the appearance of dark spots on the skin, or freckles that appear with age, in 19 of 34 people who used it.
Why some vitamin C products don’t work
Some vitamin C products aren’t made in ways that ensure the vitamin C penetrates the skin and does its job. “We have to know how to formulate them and how to package them properly,” and not all companies get it right, said Patricia Farris, a dermatologist in Metairie, Louisiana.
Vitamin C is an unstable molecule and can easily degrade into a molecule that doesn’t help skin, Bowe explained. For example, ascorbic acid, a form of vitamin C found in many skin care products, degrades when exposed to heat, high pH or sunlight, she said, which can happen during shipping or storage.
Even if the vitamin C in a product remains stable, it may not penetrate the skin deeply enough to provide benefits. The outer layer of the skin repels water-soluble molecules, such as ascorbic acid, and that means the molecules may not be absorbed sufficiently, Bowe explained.
Other vitamin C derivatives, such as tetrahexyldecyl ascorbate and ascorbyl tetraisopalmitate, have a different chemical makeup and can more easily penetrate the outer layer of skin, so some products contain these forms of the vitamin, Bowe said. Such formulations may also be gentler on the skin.
But these forms of vitamin C are relatively new and have not been the subject of much research to support their benefits, Fahs said. “The reality is that human studies demonstrating their efficacy are still very limited,” she said.
How to choose a product with vitamin C
Fahs recommends that if you’re considering a vitamin C product that contains ascorbic acid, look for a formulation that also contains vitamin E and ferulic acid, which can improve the stability of vitamin C and the way it penetrates the skin.
Bowe suggested that to maximize the chances of a vitamin C product working, choose one that is packaged in a dark container that uses a pump applicator, not a dropper. These features will help prevent the vitamin C from degrading.
Farris recommended using vitamin C products made by large, trusted skin care companies, such as SkinCeuticals, which are more likely to conduct clinical trials to test the products’ efficacy than smaller companies.
Because ascorbic acid sometimes causes irritation, people with sensitive skin or rosacea may prefer to use a product that contains one of the milder forms of vitamin C, such as tetrahexyldecyl ascorbate, Fahs said.
Still confused about what, if anything, to buy? Bowe suggested consulting with a dermatologist, though some doctors may be better informed about the research than others.
“We shouldn’t be afraid to ask questions to optimize our skin care. We have the right to find the products that work best for our skin’s needs,” Bowe said.