I’ve always been skeptical of hyaluronic acid. The water-loving molecule is touted amongst beauty pros as a miracle ingredient. When used in skincare, it’s deemed the ultimate hydrating skin plumper. But...the many times I’ve tried hyaluronic acid-infused serums, the results haven’t wowed me. Truthfully, I haven’t noticed much of a difference whether I add it into my routine or not.
That’s why I was so intrigued when I met Mimi Kim, a K-beauty entrepreneur who developed a disruptive way to offer hyaluronic acid: freeze-drying it. Yes, freeze-dried—as in what astronauts rely on in space. Kim is a walking advertisement for her product, thanks to her glass skin. She has spent over three decades launching beauty products and is also an esthetician and nutritionist. Her latest venture, Saro de Rúe, offers kits containing freeze-dried hyaluronic acid tablets, as well as an activating serum to dissolve them ($45 for eight capsules or $170 for 32, plus the serum). Since it is freeze-dried, it’s more concentrated than typical HA serums.
It sounded too good (and too cool!) to be true. To fact-check it, I consulted with board-certified NYC dermatologist Dr. Daniel Belkin. "Hyaluronic acid is a very good humectant, which means that it draws water in, so it can carry multiple times its weight in water," Dr. Belkin explains. "When you freeze-dry it, you’re basically turning it into its dry weight. You’re getting out all of the water so that you can pack a ton of it into a small space."
This was enough to convince me that I needed to give this revolutionary form of hyaluronic acid a try. As a new mom who is still nursing, I’m blocked in terms of what I can apply to my face to smooth wrinkles. While ingredients like retinol are out, hyaluronic acid is considered safe to use. Plus, I have plenty of skin concerns to tackle: lackluster complexion, lingering postpartum melasma, enlarged pores due to mask-wearing, and etched in fine lines. But before I started cocktailing my own hyaluronic acid serum at home, I learned all about how and why it works.
What Inspired Freeze-Dried Hyaluronic Acid?
Kim first discovered freeze-dried hyaluronic acid when she read about a team of Korean Pharmaceutical PhDs using sheets of 100-percent freeze-dried hyaluronic acid for medical purposes. "I was totally intrigued by that hyaluronic acid technology," Kim says. "They were using it as a wound-healing dressing for surgery. [It helps] speed up the healing process."
After learning more about the product and experimenting with these sheets at home, Kim realized they could also be used in skincare. She dreamed up the idea to put it into capsule form and marry it with a serum. To make it more consumer-friendly, Kim packaged the freeze-dried sheets into trendy tablets. "I’ve been in the beauty and health industry, and I take supplements daily," she shares. "I wanted to make it look like a supplements tablet." It took three years for Kim to bring the finished product to market.
What Is Freeze-Dried Hyaluronic Acid?
The freeze-dried hyaluronic acid sheets Kim originally discovered dissipate the instant they touch skin (doctors pick them up using sterilized pincer tongs). "If I made the tablet 100-percent hyaluronic acid, once you popped it out, it would just dissolve," she explains. This would obviously be a problem for us regular folks at home, so Kim tweaked the formula to contain 98.5% hyaluronic acid. She also added two other ingredients: squalene and vitamin E. These oils stabilize the HA and offer an extra dose of hydration.
While Saro de Rúe has less hyaluronic acid than the original freeze-dried sheets, it offers significantly more than most serums. Typical serums combine (and ultimately dilute) hyaluronic acid with water and other skin-hydrating ingredients, all in one bottle. The Saro de Rúe system separates them, ensuring you can get a more potent dose of HA per application. Kim claims one capsule is equal to the amount of hyaluronic acid found in six bottles of regular HA serum. (Similar products featuring vitamin C powders have already hit digital shelves.)
In the Saro de Rúe kit, the freeze-dried hyaluronic acid binds to the serum, dissolves, and can then be applied to your skin. The serum itself offers additional skincare benefits. "For wrinkle reduction, there's adenosine," explains Kim. "For brightening, there’s niacinamide. For skin-soothing and calming, there’s allantoin." It also features beneficial botanicals, including pomegranate, purslane, and white mulberry fruit extract. And yes, the serum does contain water, too. In fact, you could theoretically skip the serum and just combine the capsules with H2O, and it would still work.
Even though it sounds great in theory, Dr. Belkin did offer one piece of insight that's worth noting. "It’s probably a really great moisturizer," he says. "Because it’s concentrated in hyaluronic acid, you’re getting a lot of it on your skin. The questions I have are: How much hyaluronic acid can your epidermis [the top layer of skin] really take? Is it linear, in that the more you get, the more your skin plumps? Probably not. There is probably a limit in which you can’t absorb any more."
How Do You Apply It?
The capsules are packaged individually to ensure freshness. Once you pop one tablet out, you should use it right away. Each capsule feels like a soft, delicate dried sponge. To use it, place a tablet in your palm. Add the serum (I did about four big drops) and watch the tablet melt into the liquid. Mix it using your hands, and press it into the skin. I’ll admit I always felt a sense of urgency to use it quickly before it absorbed into my palm. So, be ready to "go" once you activate the tablets.
Kim recommends using your fingertips to apply it. "I’m an esthetician, so I like to use the fingertips for a more precise application," she notes. "I like to massage myself." I attempted to do this, but I often just smushed my palms together and slathered on the serum. Focus the serum anywhere you get fine wrinkles, such as around your eyes, forehead, lips, and neck.
Kim suggests using the kit before bed because hyaluronic acid works best when it is layered under products that can enhance it, like oil and night cream. "Layer, layer, layer to protect from water loss," Kim advises. "I would rather use it at night, seal it in, and sleep so that it plumps [my skin] all night. In the morning, you can see the brightness." Theoretically, you could apply it in the morning, but you might not want to wear heavy skincare under makeup.
After applying the freeze-dried HA serum mixture on bare skin, it is recommended to wait 10 to 15 seconds for it to dry. While it seeps into the skin almost instantly, it can feel a bit sticky at first. I waited a bit longer (about five minutes) to let it fully dry and avoid any pilling on top of it.
Since freeze-dried hyaluronic acid is so potent, you can likely use it less often than you would a typical HA serum. In the beginning, Kim recommends using Saro de Rúe every day to see optimal results, and then cut back to using it every other day or every three days. I found this to be pretty accurate.
What Results Can You Expect?
The claims are vast. Ask Kim, and she’ll rattle off benefits including increased skin density (re: bounciness), improved hydration, brightness (including the lightening of dark spots), tighter pores, fewer wrinkles, smoother texture, and a more lifted look (especially around the jaw and jowl lines).
When it came to smoothing the appearance of wrinkles on my expressive forehead, I definitely appreciated glossier skin in the morning. But it didn’t last more than a day (unless I used it again). "Especially with aging skin, moisturizer can help to smooth out very fine by plumping up the cells in the epidermis (the super top layers of skin)," Dr. Belkin explains. "But it’s not going to plump up the dermis, where the wrinkles are coming from. To plump up the dermis, you have to inject it."
The number one benefit I noticed was brighter skin. This happened after just a few nightly uses. While the serum contains skin-brightening niacinamide, I was curious if the HA played into this, as well. "Hyaluronic acid itself is not a brightener, but you are plumping the top layer of skin," Dr. Belkin explains. "Sometimes the dullness of skin is from roughness and flakiness, so light refracts instead of reflects. If you can plump up the epidermis, then you can get more light reflection, which can look glowy."
The most surprising benefit was that my pores did appear smaller. Dr. Belkin confirms the serum could be responsible for this. "By plumping up epidermis (like with any moisturizer), you can get the appearance of smaller pores," he says. "If you use something really hydrating or moisturizing, and you can get some plumpness of [cells] in the epidermis, it kind of squeezes the pores so that they can look smaller."
I knew it was working when my husband, who (scout’s honor) didn’t know I was writing this story and rarely comments on my face, casually said, "Your skin looks good." Did it look like I just had a bunch of professional cosmetic treatments? No. The results are not that dramatic. But it’s definitely smart skincare that performs.
While I was admittedly gifted this product, it’s actually one I’d buy. I genuinely enjoyed the ritual of dissolving the freeze-dried tablet and applying it to my skin. It felt fun and fancy to use versus just pumping out a regular ole serum. "It’s a process, which I think people like," adds Dr. Belkin (though he did also call it a bit gimmicky). "Take a capsule, wet it, create a new formula, and then apply it. You can feel like you’re a chemist."