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What is an acid mantle and how does it protect our skin?

I’m going to be honest and admit that I only heard about the acid mantle recently. I know it’s my job to stay current with wellness trends, but frankly, I thought it was a drug thing. In case, like me, you’ve been out of the loop, an acid mantle is the protective oily film that coats the skin and supposedly protects not just the skin, but the whole immune system. Before you sprain a muscle with your side eye, here’s what dermatologists say about the function of this mystical, invisible barrier.

The acid mantle is not a myth, but it might be a misnomer

“The acid mantle is a thin layer on the skin composed of a mixture of free fatty acids secreted from the oil glands mixed with lactic acid and amino acids from sweat," says Peterson Pierre, a California-based dermatologist. That’s a lot of complicated science words, so for liberal arts grads, it’s the slight film you feel on the surface of your skin most of the time, says Rachel Liverman, an esthetician and co-founder of Glowbar, a skin treatment boutique in NYC.

Not all the pros I spoke to agreed that “acid mantle” is the right phrase to use when describing this layer. “It’s not a scientific term,” says San Francisco-based dermatologist Caren Campbell. She does, however, express the importance of the skin’s protective barrier — whatever you decide to call it — which is “made up of proteins that lock in moisture and keep the outside environment out.” This function could help protect the skin from premature wrinkling and the body from invasion by bacteria.

So why is the concept of the acid mantle bubbling up now? It could be people’s current obsession with a multi-product skincare routine in the name of “self-care.” But dermatologists feel that some of the products we use regularly, ie: soap, toners, and exfoliators are damaging to the acid mantle and depleting the precious pH balance of our skin. And they might be right.

The acid mantle is kind of sensitive

Skin cleansers and toner might make your skin feel taut, tingly, and squeaky clean, Liverman explains, but that feeling probably means that the skin’s protective barrier has been thinned out. Depleting this crucial protective barrier can lead to breakouts and irritation. “The skin surface is actually acidic in its natural state,” says Tsippora Shainhouse, a dermatologist in Beverly Hills. She explains that the acid mantle can be depleted by everything from hard water to skincare products that contain sulfates. “The skin is smart and it wants to keep your skin protected,” Liverman adds.

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Shainhouse also says that toners, in particular, are a mostly outdated product that will strip the acid mantle. “Toners are not a necessary step these days,” she explains. “In the olden days, soaps were made at home of animal fat, glycerine, and lye. Toners were needed to help re-establish the natural acidic skin pH.” Exfoliation can also deplete the acid mantle. “Patients that over exfoliate with mechanical exfoliators like scrubs can cause tiny tears in their skin and the barrier which can let bacteria in. Chemical exfoliators can also impair the skin's barrier if they are overused,” says Campbell.

Protecting the acid mantle may mean cutting back on overwashing — and not just your face. “Avoiding excessive hand washing is helpful,” says Campbell. “Hand sanitizers with moisturizer have been shown to be less drying than frequent hand washing so using these if you cleanse often can be helpful.”

Protecting your acid mantle is about more than young-looking skin

“The acid mantle is very beneficial. If the pH balance is off, the skin is more prone to certain conditions such as eczema, dermatitis, rosacea, acne to name a few,” says Pierre. So if the acid mantle is stripped, the body sends extra oil to do the job, and voila, breakout. But this isn’t just about looking youthful. Shainhouse says that the acid mantle protects the skin from germs, damaging UV rays and environmental pollutants.

It’s pretty easy to take care of your acid mantle

Several of the experts I spoke with recommended CeraVe and Cetaphil products for skin care — these are relatively gentle cleansers that won’t mess with the good oils on your skin. Liverman recommends avoiding foaming products or anything that creates a stinging sensation. “The foam initially feels really good because the skin feels squeaky clean. But too much of this can cause your acid mantle to become stripped,” she says.

I was surprised that a lot of experts do not recommend coconut oil. Campbell says that coconut oil is comedogenic — meaning that it can clog your pores — and a potential contact allergen. Sunflower oil, she says, is a good alternative.

To sum it all up, whatever you call it, there is a protective layer of film on your skin. All you have to do to take care of it is not overdo anything. Don’t over wash, don’t use anything that stings, and don’t use heavy oils and your acid mantle will probably be safe.