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Hyaluronic acid, glycerin, squalane—these are all common hydrating ingredients that you've likely heard of (and are probably already using.) But there's another unsung hydrating hero that you may not yet be familiar with, though according to experts is definitely one worth knowing about. We're talking about sodium PCA, a humectant that works similarly to many of its more popular counterparts, though it also boasts a few unique distinctions.
Here, board-certified dermatologist and founder of skintour.com, Brandith Irwin, board-certified dermatologist Ife J. Rodney, founder of Eternal Dermatology in Fulton, Maryland, and StimuNail, and cosmetic biochemist Stacey Steinmetz, explain what you need to know about sodium PCA.
Meet the Expert
Type of ingredient: Humectant
Main benefits: Hydrates by attracting water to and trapping it in the skin while also helping to restore the protective skin barrier. It also has anti-inflammatory properties.
Who should use it: Pretty much anyone and everyone, given that it's both extremely well-tolerated and also has those anti-inflammatory benefits that make it suitable even for those with compromised and/or sensitive skin.
How often can you use it: Daily or even multiple times per day.
Works well with: According to Steinmetz, it works well with most ingredients. It's oftentimes paired with other humectants, especially hyaluronic acid.
Don't use with: When combined with nitrosamines such as DEA or TEA, both ingredients may be less effective and can potentially harm the skin, cautions Irwin. Look for these ingredients on the label and avoid them if possible, she says.
What Is Sodium PCA?
Bear with us here because it's a little complicated. Sodium PCA is the salt form of PCA, AKA pyrrolidone carboxylic acid, AKA pyroglutamic acid, AKA proline. Call it what you will, but it's an amino acid. Sodium PCA specifically is a natural component of the skin, making up approximately 12 percent of the skin's natural moisturizing factor or NMF, says Steinmetz. As a quick reminder, the NMF is an amalgam of different components that help keep the skin's surface supple and intact. Sodium PCA is often synthetically produced, though it can also be extracted from soybean, coconut oil, fruits, and some grasses, says Rodney. You'll most often find it in a variety of different skincare and haircare products.
Benefits of Sodium PCA for Skin
Hydration is the main name of the game, though there are a few other added benefits.
- Acts as a humectant to trap water in the skin: Like hyaluronic acid and glycerin, "it increases the water content in the top of layers of the skin by drawing moisture from the surrounding air," says Steinmetz. The big difference between it and the other two? How well it does that. Steinmetz points out that it may be up to twice as effective as glycerin at retaining moisture levels in the skin, but HA still reigns supreme among the three. "Sodium PCA can hold up to 250 times its weight in water, while hyaluronic acid holds about 1,000 times," notes Irwin. She adds that sodium PCA is also more expensive, so HA is more often used and commonly known. That being said, sodium PCA can do some things that hyaluronic acid can't.
- Restores the skin barrier: This goes back to its natural presence as part of the skin's NMF. Not only is it hydrating the skin by attracting water to it, but it's also then helping the skin better hold onto that water by bolstering the protective barrier. This makes it an especially great choice for people dealing with conditions where the barrier is compromised, such as eczema, says Rodney. To that point...
- Has anti-inflammatory properties: Not only is sodium PCA in and of itself non-irritating (more on that in a moment), but it actually can help reduce inflammation, again making it a great choice for eczema sufferers, points out Steinmetz.
Side Effects of Sodium PCA
Rodney says there are no known side effects. The only people who should avoid using it or those who have a known allergy to it and those who are allergic to coconut oil or soybean should do a patch test first, she says. Otherwise, Irwin points out that it's extremely non-irritating, while Steinmetz adds that there's no evidence of it causing sensitivity even in super high concentrations of 40%-50%.
How to Use It
It bears mentioning that it sometimes goes by other monikers on ingredient labels, including sodium pidolate, 5-Oxo-DL-proline, sodium pyroglutamate, or monosodium salt—but they're all the same thing, so don't be thrown off, says Rodney. And while it's safe to use in high concentrations, even a small amount goes a long way; as little as two percent can help re-hydrate the skin, she says. In addition, it is often paired with other humectants, and the best way to ensure you're getting the maximum benefits from all of them is to apply the product on the skin that's just slightly damp. This gives it some more water and moisture to grab onto and bind to the skin.
The Best Products With Sodium PCA
Rodney says this mist is a perfect way to "keep skin hydrated throughout the day," and indeed, one Byrdie editor loved it exactly for that reason. Along with the hydration benefits, it's packed with protective antioxidants, too, always a good thing.
"I love this cream for people with very dry skin," says Irwin. Sodium PCA, coupled with the fact that it's fragrance-free, coupled with the fact that it contains skin-soothing bisabolol (a chamomile extract), make it ideal for the sensitive set, too.
"This contains antioxidants and humectants, including sodium PCA to not only cleanse but also help hydrate and repair your skin," says Rodney of another one of her favorites. Rather than relying on potentially drying sulfates for cleansing purposes, this uses coconut-based surfactants in a gel formula that still lathers nicely.
Forget everything you thought you knew about toners drying out your skin. This 98.8% natural formula is first and foremost alcohol-free, relying on astringent witch hazel and rosewater to help balance your skin, while sodium PCA imparts the perfect amount of hydration. Rodney notes that it's an excellent choice for anyone with oily skin.
The inclusion of several different humectants—including hyaluronic acid, glycerin, and sodium PCA—makes for long-lasting yet lightweight hydration, says Rodney. Non-comedogenic and fragrance-free, it's great for all skin types, and let's not forget to mention the very wallet-friendly price, too.