Skincare ingredients A to Z: what each one does for your skin

Aloe vera

Aloe vera is a hydrating, soothing plant gel: from the plant your gran kept on the windowsill for sunburn.

What it does: its sugars (polysaccharides) hold water and ease that tight feeling after sun or shaving.

At Siwon: it’s in Handsomefyer, Splash Foam Party, Melonizer and Giggleberries.

Caffeine

Caffeine is a de-puffing, antioxidant active that reduces swelling and that purplish tinge, especially around the eyes. Same molecule as your 8 am espresso, just applied from the outside.

What it does: it constricts small blood vessels and helps drain fluid ^[8]. That’s why it’s the king of eye creams.

Heads-up: it helps with vascular dark circles and fluid-retention puffiness. Genetic dark circles or hollows… that’s a different film.

At Siwon: it’s in Banzeye and Coffee Crush. The types of dark circles explained in eye cream for men.

Centella asiatica

Centella asiatica is a soothing plant extract that helps repair the skin barrier. Traditional Asian medicine has used it on wounds for centuries (in Korea they call it “cica” and put it in everything).

What it does: its compounds (asiaticoside, madecassoside) calm irritated skin and support collagen production ^[5]. Perfect for the face that comes out of a shave as red as a lobster.

At Siwon: it’s in Wow Young, Splash Foam Party, Melonizer, Mintastic and Giggleberries.

Ceramides

Ceramides are the lipids your skin makes to protect itself: they’re about half of the fats in the outermost layer. If your skin were a wall, they’d be the mortar between the bricks.

What they do: applying them helps repair the barrier and lose less water. Very useful for skin that’s dry, tight or worn down by daily shaving.

At Siwon: we don’t use them as an ingredient in our formulas. Good to know: niacinamide helps your skin make more of its own ceramides ^[15].

Clays (kaolin, green clay) and activated charcoal

Clays and activated charcoal are purifying powders that soak up oil and take dirt with them when you rinse. They have a huge surface area that everything sticks to.

What they do: skin stays more matte and pores look smaller for a while.

Heads-up: “detox” is marketing. They clean the surface; they don’t pull toxins out of your body.

At Siwon: kaolin in Coffee Crush, green clay in Chill & Tea and activated charcoal in Mintastic.

Collagen

Collagen is the protein that gives skin its firmness and structure, and your body makes it more and more slowly as the years go by.

What it does in a cream: the molecule is too big to get through the outer layer, so it stays on the surface and forms a film that holds water and makes skin feel softer. It hydrates… and that’s it. “Collagen creams” don’t give you your own collagen back.

Heads-up: if you really want more collagen, the actives with evidence behind them are the ones that ask your skin to make it: retinol, vitamin C and peptides.

At Siwon: we don’t use it in creams. We’d rather your skin makes its own, with retinol and peptides, like in Wow Young.

Dragon's blood

Dragon’s blood is the red resin of an Amazonian tree, rich in antioxidant polyphenols and used for its soothing, repairing effect. Sounds very Game of Thrones, but local communities have used it on wounds for centuries.

Heads-up: most of the evidence comes from the lab, so we present it for what it is: a great supporting actor.

At Siwon: it’s in Dragon Shot (the name’s no coincidence), with hyaluronic acid, ginseng and vitamin E.

Ferulic acid

Ferulic acid is a plant-based antioxidant (from rice bran, oats, coffee) that stabilises vitamins C and E and boosts their protection. It hardly ever works alone: team play is its thing.

What it does: on their own, vitamins C and E oxidise easily. In a lab study on UV-exposed skin, adding 0.5% ferulic acid to a vitamin C and E formula doubled its protection against sun damage ^[4]. Fair warning: that was a lab formula, and sunscreen is still non-negotiable.

At Siwon: it’s in TAN-TAN-GO, together with vitamins C and E. More on this trio in antioxidants for your skin.

Glycerin

Glycerin is a humectant that draws water into the outer layer of the skin and probably the most widely used ingredient in all of cosmetics.

What it does: it hydrates, softens and supports the barrier, with decades of studies behind it ^[16]. Being cheap and everywhere doesn’t make it filler: few things hydrate this well for this little.

At Siwon: we don’t make a fuss about it. Look for Glycerin near the top of almost any label.

Glycolic acid

Glycolic acid is the smallest alpha hydroxy acid (AHA) there is: it comes from sugar cane and exfoliates the skin’s surface by dissolving the “glue” that holds dead cells together.

What it does: smoother texture, more even tone and less visible pores. Because it’s the smallest molecule, it gets in deeper… and stings more than lactic acid, too.

Heads-up: it makes your skin more sensitive to the sun (sunscreen the next day, no arguments), and you’re better off not using it on the same night as retinol.

At Siwon: we don’t use it in our formulas. To exfoliate without scrubbing, we prefer the gentler lactic acid in Cheeky Bum-Bum.

Green tea

Green tea (leaf extract) is an antioxidant and soothing active packed with polyphenols, the best known of which is EGCG.

What it does: it helps calm redness and is a good ally for spot-prone skin. So other people’s opinions just slide off you.

At Siwon: it’s in Melonizer and Chill & Tea.

Hyaluronic acid

Hyaluronic acid is a hydrating molecule your skin makes on its own, and it works like a sponge: it grabs water and holds it in the upper layers.

What it does: more hydration, plumper skin and less visible dehydration lines. In a study with 0.1% creams over 60 days, hydration and elasticity improved, and the low-molecular-weight versions also reduced wrinkle depth ^[6].

Heads-up: in a cream it doesn’t fill lines like the hyaluronic acid injected at a clinic. And the famous “holds 1,000 times its weight in water” sounds more impressive than what it means in practice. What matters: it hydrates, and almost everyone tolerates it, oily skin included.

At Siwon: it’s in Dragon Shot, Handsomefyer (plus the XTRA and Sun versions), Wow Young and Banzeye.

Kojic acid

Kojic acid is an active made by fermenting fungi (the same ones used for sake rice) that helps improve the look of dark spots by slowing down melanin production.

What it does: it blocks tyrosinase, the enzyme that switches melanin on, so small spots and darker areas gradually even out ^[9]. Patience required: skin tone changes over weeks, not days.

Heads-up: it can irritate sensitive skin. And be wary of anyone promising to “whiten”: its job is to help even out your tone.

At Siwon: it’s in Cheeky Bum-Bum, our tone-evening body soap, alongside niacinamide and liquorice.

Lactic acid

Lactic acid is a gentle alpha hydroxy acid (AHA) that exfoliates the skin’s surface and holds on to water as a bonus. It’s the chilled-out cousin of glycolic acid, and your skin already has it in its own natural hydration system.

What it does: it loosens dead cells without scrubbing: smoother skin and a more even tone. And it hydrates, a bonus glycolic acid doesn’t offer.

At Siwon: it’s in Cheeky Bum-Bum.

Liquorice

Liquorice (root extract) is a soothing active that helps with redness and the look of hyperpigmentation. Yes, from the same root as the sweets you used to buy as a kid.

What it does: it calms irritation and pairs really well with kojic acid and niacinamide when the goal is a more even skin tone.

At Siwon: it’s in Cheeky Bum-Bum.

Niacinamide (vitamin B3)

Niacinamide (vitamin B3) is an active that strengthens the skin barrier, regulates oil, calms redness and helps even out skin tone. The ultimate “anti” vitamin: anti-spots, anti-inflammatory, anti-blemish, anti-redness and, therefore, anti-haters. So easy-going it suits almost every skin type. (Yes, niacinamide gets on with more people than a golden retriever.)

What it does: the numbers. At 5% for 12 weeks it improved fine lines, redness, dark spots and elasticity ^[1]; at 2% it reduced oil production in 2 to 4 weeks ^[2]; it slows the transfer of pigment to surface cells ^[3]; and it helps skin make its own ceramides ^[15].

And the result? A face worth applauding in the mirror.

At Siwon: it’s in Handsomefyer (at 5%, in all three versions), Banzeye, Splash Foam Party, TAN-TAN-GO and Cheeky Bum-Bum.

Panthenol (vitamin B5)

Panthenol (provitamin B5) is a soothing hydrator that your skin converts into pantothenic acid. If life’s lottery handed you dry skin that gets tighter than a drum every winter, this is your mate on call.

What it does: it hydrates, and does it well. On top of that, several studies show it soothes and helps the skin’s natural barrier recover ^[10]: a resurrection worthy of Easter Sunday.

At Siwon: not in any of our permanent skincare products for now (it was in Cocopunch, our limited-edition soap). If you see it on a label, that’s a good sign.

Peptides

Peptides are short chains of amino acids that act as messengers: they tell the skin to make collagen or to relax expression lines. If the name sounds like a Greek god… it’s because they leave you looking like you’ve just got back from Mount Olympus.

What they do: put simply, they give your cells orders to cook up the dish of the day: collagen, elasticity, a stronger barrier. Each peptide has its speciality: some send the “make collagen” signal, others relax crow’s feet. There’s evidence, from smaller studies than those on retinol ^[11]. That’s why they perform better as a team than solo.

At Siwon: they’re in Wow Young, together with retinol, hyaluronic acid and centella.

Retinol (vitamin A)

Retinol is vitamin A in cosmetic form: it speeds up skin renewal and collagen production, and it’s the most studied anti-ageing ingredient there is. Some people eat carrots by the kilo; we’d rather smear on some retinol.

What it does: it boosts your skin’s renewal (Wolverine-style) and gets the factory running full tilt on what slows down with age: mainly collagen. It helps soften wrinkles and expression lines and improves texture. In a study with 0.4% retinol over 24 weeks, fine wrinkles improved measurably ^[12].

Heads-up: at night, starting with 2 or 3 nights a week, and sunscreen the next day. In the first few weeks it may sting or flake a bit (the famous retinisation). Visible results after 8 to 12 weeks. In the EU, the maximum allowed in face products is 0.3% ^[13].

And the result? A fresher look… better-looking than a young James Dean.

At Siwon: it’s in Wow Young, our night gel-cream with 0.3% retinol. The whole topic in detail in retinol for men.

Salicylic acid

Salicylic acid is a beta hydroxy acid (BHA) that exfoliates inside the pore: it gets on well with oil, so it goes where other exfoliants stay on the surface.

What it does: it clears pores from the inside, helps with blackheads and spots, and calms redness a little ^[7]. It’s the go-to active for oily skin, the kind that shines more than a disco ball.

Heads-up: if your skin is dry or irritated, use small amounts and only a few times a week.

At Siwon: it’s in Coffee Crush, the scrub with coffee, kaolin and shea. More on oily skin in why your forehead shines.

Shea butter

Shea butter is an emollient that nourishes and reduces water loss from the skin. It comes from the nut of an African tree: solid in the jar, it melts as soon as it touches skin.

What it does: it fills the gaps between skin cells and acts as a barrier. In a soap or scrub, it stops your skin ending up drier than a tax return.

At Siwon: it’s in Coffee Crush, Chill & Tea and Jaleo Soap.

Vitamin C

Vitamin C is an antioxidant that protects skin from sun and pollution damage, helps make collagen and improves dark spots and dull skin. The ingredient more searched-for than Britney in 2007.

What it does: it neutralises free radicals and slows down melanin production ^[14]. And that fresh morning look vitamin C gives you? Not even the Kardashians’ favourite surgeon can get you that.

Heads-up: it’s unstable (light and air oxidise it), so packaging and the chemical form matter. Best during the day, under sunscreen, with vitamin E and ferulic acid nearby.

At Siwon: it’s in Handsomefyer (with vitamin E) and TAN-TAN-GO (with vitamin E and ferulic acid).

Vitamin E

Vitamin E (tocopherol) is a fat-soluble antioxidant: it protects your skin’s lipids and helps stabilise other actives like vitamin C. We know, tocopherol sounds like a prison nickname, but it does far more good than harm.

What it does: it softens skin and extends the life of other actives: the little blue pill of skincare.

And the result? Better defended against weather, pollution and free radicals (not angry anarchists).

At Siwon: it’s in Dragon Shot, the shine-control day moisturiser, Handsomefyer and TAN-TAN-GO.