Have you ever wondered what keeps your skincare products fresh and mold-free? The answer is preservatives, and sodium benzoate is one of them. "Sodium benzoate is used in many industries, typically the food, beverage and cosmetic industries," explains Neda Mehr, MD, a board-certified dermatologist. "It is best known as a preservative, essentially an artificial compound that helps extend shelf life." We asked Mehr and board-certified dermatologist Joshua Zeichner, MD, to tell us more about this ubiquitous ingredient.
Commonly found in commercially available skin care products, sodium benzoate can be spotted on the ingredient list for virtually everything in the category, including lotions, moisturizers and serums. Keep reading to learn more about sodium benzoate in skin care.
Sodium Benzoate for the skin
TYPE OF INGREDIENT : Curator
MAIN ADVANTAGES : Extends the shelf life of skin care products
WHO SHOULD USE IT: It is found in many skin care products, but those with sensitive skin should avoid it.
HOW OFTEN CAN YOU USE IT : Depends on the product formulated
WORKS WELL WITH : Most of the other ingredients
DO NOT USE WITH : Vitamin C/ascorbic acid
What is sodium benzoate?
"Sodium benzoate is a preservative used in skin care products to prevent the growth of microorganisms that contaminate the product itself," Zeichner explains. "Unfortunately, the farm-to-table model does not work in skin care. In order to give skin care products shelf life, they must contain preservatives to prevent the growth of microorganisms such as bacteria and fungi.
Benefits of sodium benzoate for the skin
Sodium benzoate has no known benefits for the skin, but its ability to extend the shelf life of your skincare products does impact your routine. "It's a preservative that means you don't have to get a new skin care product every month," Mehr explains. "It can extend the shelf life up to two years, so that's a benefit."
Side effects of sodium benzoate
"Sodium benzoate is generally well tolerated, although it can actually cause a skin rash known as allergic contact dermatitis," says Zeichner. "This can be more common in people with eczema or a history of skin allergies."
There are other preservative alternatives to sodium benzoate that are less likely to irritate the skin. "The FDA doesn't ban its use because it's pretty hard to maintain the shelf life of your products," Mehr says. "But there are other compounds and I think we need to make that shift as an industry to some of the other compounds."
When combined with vitamin C or ascorbic as a preservative. It can turn into benzene and become a potent carcinogen. "At the end of the day, it's definitely to be avoided," Mehr says. "And I think because it's not banned, it's rampant in consumables that are not clean and not developed by dermatologists." For this reason, it's important that people with sensitive skin and conditions like eczema and rosacea (how to treat rosacea) avoid sodium benzoate because they already have a compromised skin barrier and its absorption will be amplified in these patients.
If heated, it can become more unstable and reactive, so Mehr recommends storing your skin care in a cool, dry place.
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How to use it
Since sodium benzoate is not used alone, you may want to follow the instructions of the products it is formulated with. While there isn't enough research to determine the exact amount of use at which sodium benzoate becomes dangerous, Mehr warns that it basically comes down to the surface you apply it to. "It's OK to apply it only to your face, but I would be more concerned if it was a body wash that you wash your whole body with, or a body lotion that you moisturize with every day after a shower," she explains.
"Because it's not like a natural compound that occurs in the human body, it's concerning," Mehr says. "It's important that we consider that it's a precursor to benzene, even though it's a preservative that can increase shelf life. I think that's the take-home message for sodium benzoate."
It is most often used as a preservative. It is an antifungal agent and also fights bacteria.
Although it is not considered a threat in small doses, when mixed with vitamin C, it can turn into benzene, a carcinogen.
While it is tolerated by most, those with sensitive skin, conditions such as eczema or rosacea, or a history of skin allergies, should play it safe and avoid sodium benzoate.