Koreans have always put food on their faces. A cool slice of cucumber over tired eyes, a smear of honey, mashed potato on a sunburn — every grandmother kept a recipe. What is new is which foods, and how seriously we now mean it.
Lately the ingredients migrating from the kitchen to the bathroom shelf are the ones we have eaten for centuries. Ssuk, the mugwort that flavors rice cakes and spring soups; cica, the centella that used to be a folk poultice for scrapes; and, more and more, rice ferment — the same yeasty culture that turns rice into makgeolli. Follow K-beauty long enough and you start doing a small double take at the ingredient list. Wait, that is food. That is what my grandmother brewed.
There is even an origin story. Decades ago someone noticed that sake brewers, hands sunk all day in fermenting rice, had the smooth, unlined hands of far younger people — and a whole category of fermented skincare grew out of that single observation. I think about it most nights, patting a lotion full of rice-ferment extract into my cheeks, quietly amused that I am paying a premium to rub brewing byproduct on my face.
Walk into any Olive Young and you see the entire arc laid out. Shelves of fermented essences and serums to smooth on, and right beside them, "inner beauty" ferments in capsule form to swallow. That second shelf is the tell. Because in Korea, good skin never really started at the counter. It started in the gut.
Source: Ligaya Mishan, "At the Korean Restaurant in Our Top 5, It's All About Fermentation," The New York Times, May 19, 2026. nytimes.com
The Glow Starts in the Gut
No one has staked more on that idea than the chef Hooni Kim. According to the New York Times, when its critic sat down at his restaurant Meju in Queens — where he ferments and ages his own soybeans — she found a kitchen built on fermentation where, as she put it, "food is medicine first." The paper gave it three stars and ranked it fourth among the city's hundred best restaurants. On the night the critic visited, the Times reported, Kim turned down the music and told the room: "We hope your meal tonight is delicious. But that is not our mission."
Kim puts it more plainly himself. What drew him to Korean food, he says, was never only the flavor but the history — "food has always been associated with medicine in Korea." The mechanism, in his telling, is fermentation. "Our food is based on fermentation, natural, wild fermentation," he says. "Our food is based on healing the gut." And then the line that stays with me: "Modern science now is saying the gut system is responsible for our physical health, our mental health. Koreans have known this for a thousand years."
He makes a bigger claim than I would — that eating this way can head off the diseases modern life hands us — and I would let the scientists argue the edges of it. But the spine of what he says has gone mainstream. Researchers call it the gut-skin axis: the two-way traffic between the microbes in your intestine and what surfaces on your face, the redness, the breakouts, the dullness or the glow. A gut running on a diverse, well-fed microbiome tends toward lower inflammation, and lower inflammation tends to read on the skin. Fermented foods feed exactly that system, delivering live cultures and the useful byproducts they leave behind. In one 2021 Stanford trial, ten weeks of a fermented-food-rich diet measurably raised gut-microbiome diversity and lowered markers of inflammation.
This is the honest version of "eating your skincare." Not that a single bowl erases a blemish by morning — nothing does — but that the lit-from-within skin K-beauty now sells in a bottle has always had a quieter source at the table. And the oldest, deepest source Koreans have is not a capsule. It is a clay jar of jang.
Jang, Up Close
Three jars anchor every Korean kitchen. Doenjang is a fermented soybean paste; ganjang is the soy sauce drawn from the same crock; gochujang is the red chili paste that gets all the attention abroad. All three begin as meju — blocks of cooked soybeans left to grow their own microbes in open air, inside earthenware called onggi, across a full year. No lab starter, no shortcut. Just soybeans, salt, sun, and whatever good bacteria the air carries in.
For most of Korean history this was not a wellness choice; it was how you got through a winter. But survival undersells it. A spoon of doenjang stirred into a pot did two jobs at once — it made dinner taste of something, and it slipped a daily dose of living microbes into the body, centuries before anyone had the word probiotic. My grandmother would have laughed at the word. She just knew the household that kept a good crock kept its health.
Not all jang carries that, and it is worth knowing why before you trust any jar. Kim is blunt about the reason: "Traditional Korean jangs are made from meju, where the probiotics are born in nature," he says, and those wild-fermented versions hold far stronger microbes "beneficial to your gut." The doenjang stacked in most supermarkets is a different creature — inoculated with a single lab-grown strain and pushed to the shelf in weeks, flat in flavor and short on active cultures. The real thing takes a maker willing to give a crock its full year.
You can taste the difference, which I trust more than any label. A well-aged doenjang is dark and almost meaty, savory in a way that lands late and lingers, with a faint sweetness under the funk — the flavor Koreans mean when they say a jang has settled. The fast version tastes like a rough sketch of that, thin and one-note. Once you have had the real thing off a plain spoon, you never mistake one for the other again.
The Skincare You Eat
Make the stew once and the whole idea lands in your mouth. Doenjang, hot water, soft tofu, a handful of zucchini, ten unhurried minutes — and the kitchen fills with the smell a crock gives off the moment its lid lifts. Before the rice, before anything, you taste the broth off the tip of the spoon. Warm, deep, a little wild. That first plain sip is the point.
Notice what your body does with it. There is none of the tight, just-exfoliated squeak of a serum, no sting, no fifteen-minute wait to see whether your skin agreed. There is just a bowl going down warm, the way it has for a thousand years, doing its slow work somewhere you cannot photograph. You will not glow by morning. Nobody does.
But eat this way through a season — a bowl of doenjang jjigae here, a smear of ssamjang on a lettuce wrap there, ganjang where you would have reached for plain salt — and the change, when it comes, arrives the way real change does. Quietly, from the inside, in the mirror on an ordinary Tuesday when your skin simply looks calmer and you can't quite say why. That is the gut keeping its side of a very old bargain.
It is worth saying plainly, because the beauty aisle rarely will. This is not instead of your essence. Wear the fermented serum if you love it — I do. Just know that the word doing the selling on that label, fermented, points straight back to a jar your great-grandmother tended, and that the most powerful version of it was never meant for your face. It was meant for your bowl.
Bring It Home
The gentlest way in is a pot of doenjang jjigae, the everyday stew the paste was practically built for. From there doenjang thins into a dressing for blanched greens, deepens a marinade for grilled meat or mushrooms, and, mixed with a little gochujang, becomes ssamjang, the dab you tuck into a lettuce wrap. Start with the stew, then let it wander.
It flatters plain short-grain rice and anything green and slightly bitter; to drink, keep it easy with roasted-barley tea or a dry, cloudy makgeolli that rhymes with the ferment. One ratio worth memorizing: about a tablespoon of doenjang per cup of water or stock, brought only to a gentle simmer rather than a hard boil, which flattens the aromatics you waited a year for. If you are buying rather than making, seek a naturally fermented, long-aged jang over a fast lab-inoculated tub — it is the single choice that changes everything downstream, in flavor and in the cultures still alive in it.
Stored well, it more than earns its keep. Keep an opened tub refrigerated and it holds for many months, often past a year, mellowing rather than spoiling as it goes; a flat, pale film on top is usually harmless yeast you can scrape away before you dig in — though fuzzy or colored mold, blue, green, or pink, is a different story and means the jar should go. When in doubt, trust your nose: doenjang should smell deep and savory, never sour-sharp in a way that reads as wrong.
The Oldest Skincare Was Dinner
Strip away the trend language and the "inner beauty" story is not new at all. Long before serums and supplements, Korea treated the gut and the table as the first place health is built — not through a miracle food, but through a daily way of eating that kept flavor and nourishment in the same spoon. That is the quiet joke underneath the whole K-beauty boom: the ferment was always meant to be eaten first, and giving it to your skin is the modern afterthought, not the origin. So keep the essence if it makes you happy. Then go open a jar of the real thing, taste it plain off the spoon, and feed the part of you that was doing the work all along.
FAQ
What does doenjang taste like, and how do I use it first?
Doenjang is a deeply savory, salty fermented soybean paste with a nutty, almost meaty backbone and a faint sweetness at the end. It is intense on its own, so it is almost always cooked into something rather than eaten straight. The easiest entry point is doenjang jjigae, a quick stew of the paste, soft tofu, and vegetables simmered in water for about ten minutes. From there it works as a marinade base, a dressing for blanched greens, or, blended with gochujang, as ssamjang for wraps.
What is the difference between traditional doenjang and the supermarket version?
Traditional doenjang is fermented slowly from meju using wild microbes from the open air, then aged in onggi crocks for a year or more, building both deep flavor and a rich, active microbial mix. The supermarket kind is usually inoculated with a single lab strain and finished in weeks, giving a milder, more uniform, thinner-tasting paste. Chef Hooni Kim describes the naturally fermented type as carrying far stronger probiotics beneficial to the gut. You can taste it: real aged jang has a settled, lingering depth the fast version never develops. Traditional jang like this — long-aged and naturally fermented — is what Kim'C Market stocks, if you would rather buy the real thing than track it down yourself.
Is eating fermented food really "skincare," or is that just marketing?
Eating fermented food is nourishment with a plausible skin benefit, not a topical treatment you happen to swallow. The established part is that fermented foods add microbial diversity to the gut and may lower inflammation, and the gut-skin axis links that internal state to clearer skin; the overstated part is any promise of a visible glow by a set date. No honest source claims a spoon of jang clears your complexion on its own. Treat it as a steady daily input, one of many, rather than a cure.
Is doenjang the same as gochujang?
Doenjang and gochujang are both fermented Korean pastes, but they are not interchangeable. Doenjang is a savory, salty soybean paste that forms the backbone of soups and stews, while gochujang is a sweet-and-spicy red chili paste used more as a seasoning or condiment. Plenty of Korean dishes use both, and mixing the two makes ssamjang, the dab for lettuce wraps. If you are stocking just one to start, doenjang is the everyday workhorse.
How do I store doenjang, and how long does it keep?
Doenjang keeps for many months, often well over a year, refrigerated in a sealed container after opening, mellowing rather than spoiling as it ages. A pale surface film is usually harmless yeast that can be scraped off, though you should trust your nose and discard anything that smells sharply sour or off. Buy an amount you will use within a season or two so it stays at its best, and keep it cold and tightly sealed between uses.