Skin science article
9wishes Calm Ampule Serum Versus iUNIK Black Snail Restore Serum
9wishes Calm Ampule Serum Versus iUNIK Black Snail Restore Serum This calming serum is formulated around Centella Asiatica Leaf Water and Centella Asiatica Extract to calm redness and strengthen the skin barrier. This barrier-repair serum is formulated around
9wishes Calm Ampule Serum Versus iUNIK Black Snail Restore Serum
This calming serum is formulated around Centella Asiatica Leaf Water and Centella Asiatica Extract to calm redness and strengthen the skin barrier.
This barrier-repair serum is formulated around Centella Asiatica Leaf Water and Niacinamide to strengthen the skin barrier and calm redness.
What's inside
Key Ingredients
No key ingredients
Benefits
Concerns
No concerns
Ingredients Side-by-side
Centella Asiatica Leaf Water 55%
Centella Asiatica Extract 20%
Glycerin
Butylene Glycol
Dipropylene Glycol
Water
Aloe Barbadensis Leaf Extract
1,2-Hexanediol
Betaine
Polyglyceryl-4 Caprate
Caprylyl Glycol
Glycosyl Trehalose
Hydrogenated Starch Hydrolysate
Hydroxyethylcellulose
Allantoin
Lactobacillus/Soybean Ferment Extract
Salix Alba Bark Extract
Cinnamomum Cassia Bark Extract
Portulaca Oleracea Extract
Chamaecyparis Obtusa Leaf Extract
Scutellaria Baicalensis Root Extract
Sodium PCA
Carbomer
Arginine
Ethylhexylglycerin
Glyceryl Acrylate/Acrylic Acid Copolymer
Propylene Glycol
Dipotassium Glycyrrhizate
Pentylene Glycol
Aspalathus Linearis Extract
Glycyrrhiza Glabra Root Extract
Commiphora Myrrha Resin Extract
Perilla Frutescens Leaf Extract
Yucca Schidigera Root Extract
Centella Asiatica Leaf Water 55%, Centella Asiatica Extract 20%, Glycerin, Butylene Glycol, Dipropylene Glycol, Water, Aloe Barbadensis Leaf Extract, 1,2-Hexanediol, Betaine, Polyglyceryl-4 Caprate, Caprylyl Glycol, Glycosyl Trehalose, Hydrogenated Starch Hydrolysate, Hydroxyethylcellulose, Allantoin, Lactobacillus/Soybean Ferment Extract, Salix Alba Bark Extract, Cinnamomum Cassia Bark Extract, Portulaca Oleracea Extract, Chamaecyparis Obtusa Leaf Extract, Scutellaria Baicalensis Root Extract, Sodium PCA, Carbomer, Arginine, Ethylhexylglycerin, Glyceryl Acrylate/Acrylic Acid Copolymer, Propylene Glycol, Dipotassium Glycyrrhizate, Pentylene Glycol, Aspalathus Linearis Extract, Glycyrrhiza Glabra Root Extract, Commiphora Myrrha Resin Extract, Perilla Frutescens Leaf Extract, Yucca Schidigera Root Extract
Centella Asiatica Leaf Water
Niacinamide
Glycereth-26
Snail Extract
Polygonum Cuspidatum Root Extract
Oryza Sativa Extract
Coffea Arabica Seed Extract
Laminaria Japonica Extract
Sesamum Indicum Seed Extract
Solanum Melongena Fruit Extract
Camellia Sinensis Leaf Extract
Cynanchum Atratum Extract
Chamomilla Recutita Flower Extract
Rosmarinus Officinalis Leaf Extract
Centella Asiatica Extract
Adenosine
Sodium Polyacrylate
Xanthan Gum
Sodium Hyaluronate
Water, Centella Asiatica Leaf Water, Glycerin, 1,2-Hexanediol, Butylene Glycol, Niacinamide, Glycereth-26, Snail Extract, Scutellaria Baicalensis Root Extract, Polygonum Cuspidatum Root Extract, Oryza Sativa Extract, Coffea Arabica Seed Extract, Laminaria Japonica Extract, Sesamum Indicum Seed Extract, Solanum Melongena Fruit Extract, Dipotassium Glycyrrhizate, Camellia Sinensis Leaf Extract, Cynanchum Atratum Extract, Chamomilla Recutita Flower Extract, Rosmarinus Officinalis Leaf Extract, Centella Asiatica Extract, Arginine, Carbomer, Adenosine, Ethylhexylglycerin, Sodium Polyacrylate, Xanthan Gum, Sodium Hyaluronate, Pentylene Glycol, Caprylyl Glycol
Reviews
Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
1,2-Hexanediol is a synthetic liquid and another multi-functional powerhouse.
It is a:
Humectant, drawing moisture into the skin
Emollient, helping to soften skin
Solvent, dispersing and stabilizing formulas
Preservative booster, enhancing the antimicrobial activity of other preservatives
Arginine is a semi-essential amino acid. This just means our bodies can product a bit on its own, but sometimes needs a little boost from food sources.
It is a part of your skin's natural moisturizing factor (NMF), or the water-loving molecules in your outermost layer of skin (stratum corneum) that keeps everything hydrated and happy.
Here's an interesting thing about Arginine: your skin converts it into urea through the Krebs-Henseleit urea cycle. Urea is one of the most effective humectants your skin naturally produces.
A clinical study showed applying 2.5% arginine hydrochloride to atopic dermatitis skin showed significant urea levels in the stratum corneum and improved moisture in just four weeks.
Arginine is also a precursor to nitric oxide; nitric oxide improves microcirculation and supports wound healing and collagen synthesis.
One study found that an amino acid complex containing Arginine reduced skin irritation, improved hydration, and accelerated skin repair in clinical / in-vivo studies.
Arginine itself is an amino acid and not a fatty acid, oil, or ester. On its own, it's not a direct food source for Malassezia, or the yeast that causes fungal acne.
Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:
Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.
Though this ingredient works well with most skin types, some people with sensitive skin may experience a reaction such as allergic rashes, closed comedones, or itchiness.
Caprylyl Glycol is a humectant, skin conditioner, emollient, and preservative booster derived from either caprylic acid or synthetically created.
Typical use levels vary from 0.3-1% as a preservative booster and go up to 2% to condition skin.
Because it is not a free-fatty acid, this ingredient is fungal acne safe (there's nothing for Malassezia to feed on).
Carbomer is a synthetic thickening and gelling agent. It's basically the ingredient that gives a lot of serums, gels, creams, and sunscreens their smooth, non-sticky texture.
Although legally permitted at very high levels, carbomers are normally used at concentrations below 1%.
It also needs to be neutralized to actually thicken, and because it is a large molecule, it doesn't really penetrate the skin barrier.
Allergy-wise, the risk is very low. Clinical studies show carbomers have low potential for skin irritation/sensitization even at concentrations up to 100%.
A 2024 UK study patch-tested 1,302 patients and found true allergy to the parent group of carbomer to be rare with no confirmed relevant reactions.
Centella Asiatica Extract (Centella) is one of the most researched botanical extracts in skincare with decades of studies backing its effects on inflammation, collagen, and the skin barrier.
That research keeps pointing back to the same four triterpenoid saponins: Asiaticoside, Madecassoside, Asiatic Acid, and Madecassic Acid.
These compounds allow centella to dial back inflammation, encourage the skin to build and hold onto collagen, support the barrier and hydration, and bring solid antioxidant activity to protect against signs of aging.
Centella also carries a nice supporting cast of Vitamin A, vitamin C, several B vitamins, and amino acids. Put it all together and you get an ingredient that soothes, hydrates, and protects, all at once.
Most of centella's magic comes from the four big compounds (Asiaticoside, Madecassoside, Asiatic Acid, and Madecassic Acid). These are the actives doing the heavy lifting in almost every centella study.
Here is the short version of what they do in the skin:
So it is not just soothing for the sake of soothing. Centella calms the skin AND helps it rebuild.
Just FYI, not all centella on an ingredient list is the same. What you are getting actually depends on the extract:
Fun fact on the ratios: the leaves tend to be richest in Madecassoside and Asiaticoside, and lower in the two acids. The exact amounts shift with where the plant is grown and how it is processed. This means purity really does vary brand to brand.
Centella is one of the most easygoing actives out there.
It layers well with basically everything: niacinamide, hyaluronic acid, peptides, and vitamin C, and also pairs nicely with stronger actives like retinoids and exfoliating acids where it can help take the edge off irritation.
On the safety side, centella and its triterpenes are classified as weak sensitizers, meaning allergic reactions are possible but uncommon.
Patch tests at 1% and 5% came back negative in test panels, and creams at typical use levels did not cause allergic reactions across large groups of people.
But as with any new active, a patch test is still a smart move for very reactive skin.
Centella is widely used because it is effective at low percentages. For context, human safety testing found no meaningful irritation from creams containing centella extract at everyday use levels (the tested amounts were well under 1%).
The irritancy threshold in animal testing was also above 30% (so real-world formulas sit far below anything concerning).
In collagen lab studies, higher concentrations drove more collagen synthesis, so serums built around centella tend to feature it more prominently.
Bottom line: you will find centella working nicely anywhere from a fraction of a percent up to hero-ingredient levels depending on whether it is a supporting soother or the main event.
Fun fact: Centella has been used as a medicine and in food for many centuries. As a medicine, it is used to treat burns, scratches, and wounds.
Centella Asiatica Leaf Water is created by distilling centella asiatica leaves. Centella Asiatica is a herb native to Southeast Asia.
Many active components found in Centella Asiatica Extract, such as Madecassic Acid and Asiaticoside, encourage the skin to naturally produce hyaluronic acid. This helps keep our skin hydrated. Many of these components also show antioxidant activity and may help reduce the signs of aging.
Other components of Centella Asiatic Extract include Vitamin A, vitamin C, several B vitamins, and Asiatic Acid.
Dipotassium Glycyrrhizate comes from licorice root.
Extracts of licorice have demonstrated to have antibacterial, anti‐inflammatory, antiviral, antioxidant properties.
One component, glabridin, has extra potent antioxidant and soothing properties. It has also been found to block pigmentation from UVB rays in guinea pigs.
Licorice Root also contains a flavonoid. Flavonoids are a natural substance from in plants. Flavonoids also have antioxidant properties.
Another component, glycyrrhizin, has been found to have anti-inflammatory and antimicrobial benefits. This may make licorice root extract effective at treating acne. However, more research is needed to support this.
Liquiritin is one of the flavone compounds found in licorice. It has been found to help lighten skin by preventing tyrosinase from reacting with tyrosine. When the two react, protein is converted to melanin. Melanin is the substance in your body that gives your features pigmentation.
Licorice root is native to Southern Europe and Asia. It has been used in traditional Chinese medicine to help with respiratory issues.
Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.
Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Topically, glycerin does several things at once:
Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.
Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.
This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.
Just know very high concentrations (>40%) can feel tacky in low humidity.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Pentylene Glycol (1,2-pentanediol) is a multitasking little diol with three main roles in a formula:
Research on alkanediols (the family pentylene glycol belongs to) show they work by disrupting microbial cell membranes. This disruption helps the primary preservative system in a product work more effectively at lower doses.
On the safety side, the Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe as used in current cosmetic practices + concentrations.
Typical use levels in a formula run about 1-5%.
Scutellaria Baicalensis Root Extract comes from the Baikal skullcap or Chinese skullcap plant. This plant is native to Northeast Asia and can be found in China, Mongolia, Korea, and Siberia.
In cosmetics, Scutellaria Baicalensis Root Extract provides antioxidant and anti-inflammatory benefits. This is due to the flavonoid composition of Scutellaria Baicalensis Root Extract.
In Chinese traditional folk medicine, Scutellaria Baicalensis Root Extract is used to help treat lung issues and hypertension.
Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!