The K-Beauty Ingredients Glossary: What Every Active Actually Does
You are past the "what is K-beauty?" stage. You have layered a toner, you own at least one essence, and you have turned over a box, read "Galactomyces Ferment Filtrate" and wondered what exactly you were putting on your face. This glossary is a working reference for the ingredients that show up most in Korean skincare: what each one is, what it is used for, and where it sits in a routine.
Updated October 2026.
How Korean skincare approaches ingredients
Western skincare has historically been built around single high-strength actives, such as retinol, vitamin C and AHAs, used carefully, with warnings about irritation and sun sensitivity.
Korean skincare tends to work the other way. Several gentler ingredients sit together in one formula, usually on a hydrating, barrier-friendly base, and the visible change is built over weeks rather than forced in days. Korean skincare has plenty of actives. They just tend to arrive with company.
One useful thing to know before the list. Korea runs a regulated category called functional cosmetics, and for some claims it publishes the ingredients a brand may cite. Adenosine and niacinamide are both on those lists, which is part of why you see them in so many Korean formulas.
The glossary
Niacinamide (vitamin B3)
What it is: A water-soluble form of vitamin B3, and one of the most widely used ingredients in Korean skincare.
What it is used for: A more even-looking tone, the look of pores, and skin that feels more balanced. It also supports the skin's own barrier lipids, which is why it shows up in barrier-focused formulas too.
How to use it: In a toner or serum after cleansing. It layers with almost everything. Very high strengths can cause flushing in some people, so more is not automatically better.
Where you will find it in a ViaJiin routine: The Healara Radiance Shot Moisture Toner and Core Enhance Brightening Toner, both pairing it with tranexamic acid, and the Sograin So Oat Watery Cream.
Centella asiatica (cica)
What it is: A plant also known as tiger grass or gotu kola. On labels it appears as centella asiatica extract or leaf water, or as its compounds madecassoside and asiaticoside.
What it is used for: Calming skin that looks red or stressed, and supporting a comfortable barrier. It is one of the most common ingredients in Korean products made for sensitive skin.
How to use it: Anywhere in a routine. It is a good companion to a stronger active, and a staple for skin that is having a difficult week.
Where you will find it in a ViaJiin routine: All four Dr.RELIEF DAC2 products in the Barrier Repair Kit, and the VARDA PDRN Skin Booster Cica Serum, which uses centella leaf water as its base instead of plain water.
Panthenol (pro-vitamin B5)
What it is: A humectant that converts to vitamin B5 in the skin.
What it is used for: Holding water in the skin and keeping it comfortable. It is a quiet workhorse of barrier formulas.
Where you will find it in a ViaJiin routine: Second on the ingredient list of both the Dr.RELIEF DAC2 Intensive Repair Ampoule and Intensive Repair Cream.
Hyaluronic acid
What it is: A molecule that holds water. On labels it appears as hyaluronic acid, sodium hyaluronate or hydrolyzed hyaluronic acid, and Korean formulas often combine several sizes.
What it is used for: Hydration, and the plump, dewy look associated with glass skin.
How to use it: On damp skin, and always with something on top. Hyaluronic acid holds water. A cream is what slows that water down on its way out.
Where you will find it in a ViaJiin routine: The Healara toners, built on a ten-form hyaluronic complex, and the Dr.RELIEF DAC2 Zero-Pore Hyaluronic Acid Toner.
Ceramides
What they are: Lipids that make up a large share of the skin's outer barrier, the mortar between the bricks.
What they are used for: Keeping water in and irritants out. Essential for dry, over-exfoliated or reactive skin.
How to use them: In a moisturizer. They do more with company: ceramides alongside cholesterol and fatty acids, in roughly the proportions skin uses itself, rather than a single ceramide on its own.
Where you will find them in a ViaJiin routine: The Dr.RELIEF DAC2 Intensive Repair Cream (five ceramides with cholesterol and fatty acids), the Healara Core Revive Activating Cream (six ceramides with cholesterol and phytosphingosine), and the Aseriel Derma Luxe Cream (four ceramides).
Peptides
What they are: Short chains of amino acids. Formulas often combine several, listed together as a peptide complex.
What they are used for: Skin that looks less firm than it used to. Peptides are gentle, which is why they suit skin that does not tolerate retinoids well.
Where you will find them in a ViaJiin routine: The Healara Core Lift Firming Ampoule in the Restore & Nourish Kit, which carries about eleven, and the Aseriel Derma Luxe Cream, with a seven-peptide complex.
Adenosine
What it is: A molecule the body makes naturally.
What it is used for: Smoother, firmer-looking skin. It is one of the ingredients Korea's regulator lists for wrinkle-care claims, which is why it appears in so many Korean serums and creams, usually near the end of the list.
Where you will find it in a ViaJiin routine: The Vegetology Viniferine Brightening Ampoule and the Healara Core Lift Firming Ampoule.
Tranexamic acid
What it is: A synthetic amino acid derivative that has moved from clinics into everyday skincare.
What it is used for: A more even-looking tone. It is usually paired with niacinamide, and it is gentler than many traditional brightening actives.
Where you will find it in a ViaJiin routine: Both Healara toners.
Viniferine
What it is: A compound from grapevine, used in Korean formulas as a steadier alternative to vitamin C.
What it is used for: A more even, luminous-looking complexion, without the oxidation that turns many vitamin C serums brown. I wrote more about it in viniferine vs vitamin C.
Where you will find it in a ViaJiin routine: The Vegetology Viniferine Brightening Ampoule and the Viniferine Brightening Mask.
PDRN
What it is: Polydeoxyribonucleotide, fragments of DNA. Clinical PDRN has historically come from salmon and trout. Some skincare versions use other sources, and the source is rarely on the front of the box.
What it is used for: Skin that looks tired or less bouncy. A serum is not an injection, and the honest gap between the two is covered in is salmon DNA skincare actually salmon DNA.
Where you will find it in a ViaJiin routine: The VARDA PDRN Skin Booster Cica Serum, with rice-derived PDRN, confirmed by the formulator.
Snail secretion filtrate
What it is: Filtered mucin from snails, popularised in Korean skincare in the early 2010s.
What it is used for: Hydration and a smoother-looking surface. It is gentle and widely tolerated, though anyone avoiding animal-derived ingredients will want to skip it.
Galactomyces ferment filtrate
What it is: A filtrate made by fermenting yeast, used as a first essence in many Korean routines.
What it is used for: A brighter-looking, smoother-feeling surface over time. You will see it named on labels as galactomyces ferment filtrate.
Beta-glucan
What it is: A polysaccharide found in oats, mushrooms and yeast.
What it is used for: Hydration with a soothing feel. A good option for reactive skin that finds some hydrating formulas sticky or stingy.
Propolis
What it is: A resin bees use to seal their hives.
What it is used for: Calming and a healthy-looking glow, especially in skin prone to breakouts. Skip it if you are allergic to bee products.
How to read a Korean ingredient list
- Order matters. Ingredients are listed in descending order of concentration, so the top five or so make up most of the formula.
- The 1 percent line. Below 1 percent, ingredients can appear in any order. That is why many actives cluster near the end of the list.
- Complex is a marketing word. A "ceramide complex" or "peptide complex" bundles several ingredients under one name. The full list tells you what is actually in it.
- Read the Korean panel if you can. Since 2020, Korean labels have had to name 25 common fragrance allergens. An English export label is not always as complete.
What works together, and what needs space
Pairs well:
- Niacinamide with hyaluronic acid, for hydration and a more even-looking tone
- Centella with ceramides, for a calm, comfortable barrier
- Peptides with ceramides, for skin that is changing and wants firmness without irritation
Give them space:
- Exfoliating acids and retinoids. Alternate nights rather than stacking them.
- Several exfoliating acids across a cleanser, toner and essence. Count them before adding another.
- High-strength vitamin C and high-strength niacinamide. The old warning is overstated at normal strengths, but morning and evening is an easy way to avoid flushing.
Frequently asked questions
What is the difference between an essence and a serum?
Texture and purpose. An essence is lighter and mostly about hydration. A serum, or ampoule, is thicker and more targeted. Essence first, then serum.
Is niacinamide or vitamin C better for a brighter-looking complexion?
They work differently and can be used together, one in the morning and one in the evening. If vitamin C has irritated you or turned brown in the bottle, niacinamide, tranexamic acid and viniferine are gentler routes to a more even-looking tone.
Why does every Korean brand talk about the skin barrier?
Because nothing else works well without it. The barrier is the outer layer of skin, cells held together by ceramides, cholesterol and fatty acids. When it is compromised by over-exfoliation, harsh cleansing or weather, skin turns dry and reactive, and actives tend to sting rather than help. I wrote more about it in why skin that was fine last year stops being fine.
How do I know which ingredients are right for my skin?
It depends on your skin type, what it is doing right now, your climate and what you already use. A glossary can tell you what each ingredient is. It cannot tell you which four belong together on your face.
That is what the skin quiz is for. It takes three minutes and matches you to a routine, with every ingredient list on the page before you buy.
