In our Trial Run series, TZR editors and writers test the hottest new beauty products and share their honest reviews. This week, our editor tested Medicube Soy Protein Leave-In Treatment straight from Seoul, South Korea.
Because I was born with naturally curly dark chocolate hair, I believed for a long time that I could never bleach or dye it. Although I always dreamed of having hair as shiny as my makeup and tattoos, I was convinced that coloring it would just send my spirals into a downward spiral. They would surely wither into withered sticks of straw, wouldn’t they?
I discovered how wrong I was in July 2021. In a moment of spontaneity, I made an appointment with beloved colorist Aura Friedman. For reference, Zoë Kravitz, Selma Blair, Soo Joo Park, and Natasha Lyonne entrust her with their highly esteemed hair. My intuition told me that Aura would not lead my curls to their demise. (This I was right.)
About three hours later, I walked out of the Sally Hershberger salon in New York with gorgeous face-framing highlights of teal, lilac, and goo green, along with the recommendation to implement a protein treatment into my haircare routine.
My hair before and after visiting Aura Friedman.
Luckily, the Medicube Soy Protein Leave-In Treatment appeared in a candy box my friend in Seoul sent to me shortly after the big day. I’ve long been a fan of the Korean beauty brand’s anti-acne formulas, but I never thought hair care would be K-beauty’s next frontier to explore. Thanks to the Soy Protein Leave-in Treatment, my worries about curl damage have been wiped away and I have a newfound appreciation for Korean hair care products.
An Overview of Medicube Soy Protein Leave-in Treatment
OK, let me back up a bit and dive into how this hair treatment works. Much like Olaplex and K18, Medciube’s Soy Protein Leave-In Treatment relies on bond builders in the form of proteins and peptides to strengthen and repair damaged hair. Medicube’s option does this with a silky clean laundry-scented liquid housed in an ergonomic spray bottle instead of a creamy leave-in mask. (I prefer this barely there consistency as my hair is quite fine despite being curly.)
In Korea, protein-rich hair treatments are in high demand right now as young people are increasingly concerned about hair loss, says Seoul-based K-beauty industry expert Odile Monod. In fact, sales of scalp and hair loss treatments are currently up 223% year-on-year, according to Korean online retail giant Gmarket. There’s even a name for this trend: Gapless. 갭리스, in Korean, “describes a phenomenon in which young Korean consumers in their 20s and 30s are actively seeking targeted anti-aging and anti-hair loss treatments, products that were previously associated with an older population,” says Monod. .
This product prevents hair loss by strengthening hair with a truly lightweight formula that won’t weigh hair down, says cosmetic chemist Javon Ford. Isododecane is first listed as an ingredient on the treatment label. For those unfamiliar, “It evaporates very quickly from the hair, leaving behind the protein and emollient ingredients,” Ford told TZR.
The protein it refers to is made up of 11 different plant proteins from corn, soybeans, rice, potatoes, barley, almonds, and oats, to name a few- one. All pack high levels of amino acids. “Protein, in general, is good for high porosity and damaged hair,” says Ford. “They temporarily fill in cracks caused by heat or chemical damage.”
As for emollients, Ford mentions soy and sunflower oils added to the elixir. These lipids “fill in the cracks in the cuticle to help hair feel smoother,” says Ford. Coconut oil is also on the list of ingredients, which “may actually penetrate the cortex for additional conditioning,” he adds.
However, chemical compounds that aren’t exactly household names — namely isoamyl laurate and alkyl benzoate — are what do the most work in the moisturizing department, Ford says. The former especially helps hair absorb every drop of moisture.
My curls after using the soy protein leave-in treatment
Science aside, I swear Medicube Soy Protein Leave-In Treatment is all my hair needs to retain its softness, shine, and definition after all I’ve put it through. Because it’s been several months since Friedman touched my hair, I now maintain the teal color every six weeks with Shrine’s Aqua Drop It Kit.
As a general rule, I wash my hair every third day with Sky Organics Wash Day Detangling Shampoo and Conditioner. Every other time, I spray the Soy Protein Leave-In Treatment on my hair – from roots to ends – after I get out of the shower and towel dry. Then running my fingers through my hair helps distribute the product evenly. Then I’m ready. My curls look better when I let them air dry before I go to bed.
In the morning, I wake up with beautiful elastic curls. The treatment makes them so much easier to manage than they usually are even without staining. During the dry winter months, in particular, my coils get incredibly crispy and tangled. Now they are smooth, nourished and perfectly separated. I barely need to brush them with a moisturizing hair mask to revive them.
The key is not to resort to the treatment as often in order to avoid loading your hair with protein. You really only need it once a week at most to reap the rewards. “The buildup of unnecessary proteins prevents moisture from penetrating deeper into the internal structure of the hair fiber,” certified trichologist Bridgette Hill previously told TZR. As a result, the hair could become brittle and even more damaged than it was initially.
With once-a-week use of the Medicube Soy Protein Leave-in Treatment, my curls don’t look any the worse for wear. If I could naturally grow teal hair, this is what it would look like. With that in mind, I’m convinced that I should add more highlights to my hair. They can definitely handle it now with the powers of Medicube Soy Protein Leave-in Treatment in my hair care arsenal.
Do you need Medicube Soy Protein Leave-In Treatment?
Protein treatments often cost between $30 and $75 for a tiny bottle. The Medicube Soy Protein Leave-In Treatment, meanwhile, is just $29 for a 6.76 fluid ounce bottle. Because you only need a few sprays once or twice a week, the bottle lasts a few months.
Plus, you don’t necessarily need to have colored or curly hair to experience the benefits of the treatment. It also acts as a heat protectant if straightening or curling your hair is your thing. It keeps your hair nourished, smooth and shiny, whatever its condition.
Oh yes, and you don’t have to worry about asking someone to send it to you via Korea Post. Fortunately, Medicube Soy Protein Leave-In Treatment is readily available in the United States at medicube.us. And you have bragging rights that you’re ahead of the K-beauty hair care wave that’s sure to hit America soon.
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