Skin science article
Beauty of Joseon Dynasty Cream (Old Formulation) Versus iUNIK Black Snail Restore Serum
Beauty of Joseon Dynasty Cream (Old Formulation) Versus iUNIK Black Snail Restore Serum This barrier-repair moisturizer is formulated around Niacinamide and Adenosine to strengthen the skin barrier and hydrate skin. This barrier-repair serum is formulated arou
Beauty of Joseon Dynasty Cream (Old Formulation) Versus iUNIK Black Snail Restore Serum
This barrier-repair moisturizer is formulated around Niacinamide and Adenosine to strengthen the skin barrier and hydrate skin.
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
Benefits
Concerns
No concerns
Ingredients Side-by-side
Water
Glycerin
Butylene Glycol
Niacinamide
Dipentaerythrityl Hexa C5-9 Acid Esters
Sodium Hyaluronate
Xanthan Gum
Cyclopentasiloxane
Cyclohexasiloxane
Polyacrylate-13
Polyisobutene
Polysorbate 20
Hydrogenated Lecithin
C14-28 Alkyl Acid
Stearyl Alcohol
Behenyl Alcohol
Dimethicone/Vinyl Dimethicone Crosspolymer
Dimethicone
Adenosine
Glyceryl Stearate Se
Cetearyl Alcohol
Polyglyceryl-3 Methylglucose Distearate
Cetyl PEG/PPG-10/1 Dimethicone
Stearic Acid
Tocopheryl Acetate
Sodium Polyacrylate
Olea Europaea Fruit Oil
Helianthus Annuus Seed Oil
Centella Asiatica Extract
Hippophae Rhamnoides Oil
Argania Spinosa Kernel Oil
Butyrospermum Parkii Butter
Ceramide NP
Trehalose
Calendula Officinalis Flower Extract
Caprylhydroxamic Acid
1,2-Hexanediol
Raphanus Sativus Leaf Extract
Oryza Sativa Bran Extract
Cucurbitaceae Extract
Orchid Extract
Honey Extract
Panax Ginseng Root Extract
Carthamus Tinctorius Seed Oil
Phytosphingosine
Ceteareth-20
Glyceryl Citrate/Lactate/Linoleate/Oleate
Parfum
Water, Glycerin, Butylene Glycol, Niacinamide, Dipentaerythrityl Hexa C5-9 Acid Esters, Sodium Hyaluronate, Xanthan Gum, Cyclopentasiloxane, Cyclohexasiloxane, Polyacrylate-13, Polyisobutene, Polysorbate 20, Hydrogenated Lecithin, C14-28 Alkyl Acid, Stearyl Alcohol, Behenyl Alcohol, Dimethicone/Vinyl Dimethicone Crosspolymer, Dimethicone, Adenosine, Glyceryl Stearate Se, Cetearyl Alcohol, Polyglyceryl-3 Methylglucose Distearate, Cetyl PEG/PPG-10/1 Dimethicone, Stearic Acid, Tocopheryl Acetate, Sodium Polyacrylate, Olea Europaea Fruit Oil, Helianthus Annuus Seed Oil, Centella Asiatica Extract, Hippophae Rhamnoides Oil, Argania Spinosa Kernel Oil, Butyrospermum Parkii Butter, Ceramide NP, Trehalose, Calendula Officinalis Flower Extract, Caprylhydroxamic Acid, 1,2-Hexanediol, Raphanus Sativus Leaf Extract, Oryza Sativa Bran Extract, Cucurbitaceae Extract, Orchid Extract, Honey Extract, Panax Ginseng Root Extract, Carthamus Tinctorius Seed Oil, Phytosphingosine, Ceteareth-20, Glyceryl Citrate/Lactate/Linoleate/Oleate, Parfum
Centella Asiatica Leaf Water
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
Arginine
Carbomer
Ethylhexylglycerin
Pentylene Glycol
Caprylyl Glycol
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
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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
Adenosine is a purine nucleoside that your body already makes in every cell. In skincare, it acts mainly as a skin conditioning and anti-aging agent.
The way it works is fairly well mapped out:
Your skin has cells called fibroblasts that build collagen (the stuff that keeps skin firm and smooth). Adenosine basically flips a switch on these cells that tells them to get to work making more collagen and other proteins. These cells slow down on their own as skin ages, so Adenosine helps give them a little nudge to keep going.
The clinical backing is pretty solid too.
A blind, randomized, placebo-controlled trial of 126 women aged 45-65 tested a 0.1% cream twice daily and found real improvements in crow's feet and frown lines using a precise 3D skin-mapping technique; these changes showed up by week 3 and held at 2 months.
A later study using Adenosine-loaded dissolving microneedle patches reported gains in wrinkle depth, dermal density, elasticity, and hydration.
On concentrations, South Korea's Ministry of Food and Drug Safety has set 0.04% as the approved functional anti-wrinkle level. You'll typically see this ingredient used somewhere in the 0.04-0.1% range since it works at low doses.
This ingredient has been found safe for cosmetics with the data showing no irritation or sensitization.
Overall, this is a great ingredient for any anti-aging routine and has no photosensitizing effect, so it suits both AM and PM use.
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.
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.
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.
Niacinamide is a multitasking form of vitamin B3 that strengthens the skin barrier, reduces pores and dark spots, regulates oil, and improves signs of aging.
And the best part? It's gentle and well-tolerated by most skin types, including sensitive and reactive skin.
You might have heard of "niacin flush", or the reddening of skin that causes itchiness. Niacinamide has not been found to cause this.
In very rare cases, some individuals may not be able to tolerate niacinamide at all or experience an allergic reaction to it.
If you are experiencing flaking, irritation, and dryness with this ingredient, be sure to double check all your products as this ingredient can be found in all categories of skincare.
When incorporating niacinamide into your routine, look out for concentration amounts. Typically, 5% niacinamide provides benefits such as fading dark spots. However, if you have sensitive skin, it is better to begin with a smaller concentration.
When you apply niacinamide to your skin, your body converts it into nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme that is already found in your cells as "fuel" and powers countless biological processes.
In your skin, NAD helps repair cell damage, produce new healthy cells, support collagen production, strengthen the skin barrier, and fight environmental stressors (like UV and pollution).
Our natural NAD levels start to decline with age, leading to slower skin repair, visible aging, and a weaker skin barrier. By providing your skin niacinamide, you're recharging your skin's NAD levels. This leads to stronger, healthier, and younger looking skin.
Another name for vitamin B3 is nicotinamide. This vitamin is water-soluble and our bodies don't store it. We obtain Vitamin B3 from either food or skincare. Meat, fish, wheat, yeast, and leafy greens contain vitamin B3.
The type of niacinamide used in skincare is synthetically created.
Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
Interestingly, the size of the molecule affects its behavior:
Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.
Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.
You'll typically see concentrations between 0.1-2% for this ingredient.
Sodium Polyacrylate is the sodium salt of polyacrylic acid. It is used as an absorber, emollient, and stabilizer.
This ingredient is a super-absorbent polymer - meaning it can absorb 100 to 1000 times its mass in water. As an emollient, Sodium Polyacrylate helps soften and soothe skin. Emollients work by creating a barrier to trap moisture in. This helps keep your skin hydrated.
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!
Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.
On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.
Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.