I Tested 7 Korean Niacinamide Serums at Olive Young. This Is the One I Keep Repurchasing

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I’ve been using niacinamide for a long time. Not one bottle, several. So when people ask me which niacinamide serum to grab at Olive Young, I actually have an answer.

I recently went to Olive Young and swatched 7 niacinamide serums side by side on my hand. The main three are the ones foreigners ask me about the most: COSRX The Niacinamide 15, Anua Niacinamide 10 + TXA 4, and Anua Peach 70 Niacin Serum. Then four more popular serums that also have niacinamide inside. Here’s what I found, plus how I actually use the one I keep repurchasing.

Korean niacinamide serums at Olive Young: quick comparison

COSRX Niacinamide 15

Niacinamide: 15%

Best for: Oil, visible pores

Texture: Clear, watery

Scent: Barely any

My experience: Several bottles, real results

Anua 10 + TXA 4

Niacinamide: 10% (+ tranexamic acid 4%)

Best for: Dark spots, acne marks

Texture: Slightly brownish, light jelly

Scent: Barely any

My experience: Tested in store

Anua Peach 70

Niacinamide: 5%

Best for: Beginners, dry skin, hydration

Texture: Clear, light, absorbs fast

Scent: Peach (contains fragrance)

My experience: Tested in store

Niacinamide %: 5% vs 10% vs 15%, what’s the difference?

This is the question I get the most. Short answer: higher % doesn’t mean better results. It means a stronger product, and that’s not the same thing.

• Around 2 to 5%: this is the range most niacinamide studies use, for things like oil control, redness and uneven tone. For most people, this already works.
• 10%: the popular “strong” level. Fine for most normal and oily skin once you’re used to niacinamide.
• 15% and up: for people who already tolerate niacinamide well and want more oil and pore control. This is where flushing, warmth or tingling shows up more often.

Here’s how the serums in this post line up:

COSRX The Niacinamide 15

Niacinamide: 15%

Anua Niacinamide 10 + TXA 4

Niacinamide: 10%

Anua Peach 70 Niacin

Niacinamide: 5%

Avène,

Avène, numbuzin, MEDIHEAL, medicube (below)

Niacinamide: Not disclosed, a supporting ingredient

How I’d choose: if you’ve never used niacinamide, start around 5%. If your skin is fine with it after a few weeks and you want more, go up to 10%. I use 15% because my skin is oily, my pores are on the bigger side, and I’ve used niacinamide for years. Even then, I put it on after my cream so it’s a little gentler.

If your skin turns red and stays red, burns, or itches, that’s not “it’s working.” Go back down to a lower %.

1. COSRX The Niacinamide 15 Serum: the one I keep repurchasing

This is my serum. I’ve used up several bottles of it, so this part is pure experience, not a swatch test.

The label says 15% niacinamide with acetyl glucosamine and zinc PCA, and Olive Young shelves it under Oil & Pore Control (피지 케어, pi-ji ke-eo, “sebum care”). That’s exactly what I use it for. My pores are on the bigger side, and this is the one product where I actually saw a difference.

What it feels like: it’s clear and watery, but the first time I used it, it stung a lot. Really tingly. I think that’s probably the high 15%. Honestly, that’s also why it worked so well for me. It felt like it was working right away.

But if you’re sensitive to stinging, I’d skip this one. Go for the Anua Peach 70 (5%) instead. And if the stinging doesn’t fade, or you get redness that stays, burning or itching, stop. That’s not “it’s working.”

How I use it (with retinol):

• I use retinol only at night.
• Because of that tingly feeling, I don’t put niacinamide straight on bare skin. I finish my whole routine first, toner and cream included, then niacinamide, then retinol on top.
• You can also apply it right after toner, as the brand suggests. Either way, I only put it around my pores (nose, cheeks next to the nose), not my whole face.

Result: I applied it every night, diligently, and after about 1 to 2 weeks my pores looked noticeably tighter. Using it together with retinol is when I felt it the most.

If you’re new to retinol, go slow. Start a couple of nights a week, and always wear sunscreen the next morning.

Key ingredients: Niacinamide 15%, acetyl glucosamine, zinc PCA | Best for: Oily skin, visible pores | Scent: Barely any | My use: Several bottles

2. Anua Niacinamide 10 + TXA 4 Serum: the famous one

This is the niacinamide serum foreigners ask me about most. It pairs 10% niacinamide with 4% tranexamic acid (TXA), an ingredient Korean brands love for dark spots and acne marks. The Olive Young promo box literally calls it a “2-week blemish tone-up serum” (2주 흔적 톤업 세럼).

Texture, compared to the other two: the color is a little brownish, and it’s slightly thick, but not sticky-thick. More like a light, soft jelly. Keep in mind I tested the store tester, which may have been open for a while.

What Korean reviewers say: on Korean beauty review apps, the common points are that it absorbs fast without stickiness, doesn’t pill under sunscreen, and that people noticed marks fading after steady use. Some people with sensitive skin mentioned a little tingling, so patch test first.

I go deeper into dark spot serums in my Korean dark spot serum guide.

Key ingredients: Niacinamide 10%, tranexamic acid 4% | Best for: Dark spots, acne marks | Scent: Barely any | My use: Tested in store

3. Anua Peach 70 Niacin Serum: the gentler, scented one

I tried this right next to the 10+. The first thing you notice is the scent. It clearly smells like peach. Texture-wise, it felt almost the same as the 10+ on my hand, and honestly, I couldn’t tell much difference between the two just from a swatch.

The real difference is on the label. This one has 5% niacinamide (half of the 10+) and 70% peach extract, and it contains fragrance. Korean reviewers mostly describe it as a hydrating serum: light, absorbs fast, not sticky, and sits nicely under sunscreen. It gets the most love from people with dry skin.

Pick it if you want a gentle, lower-strength niacinamide serum that feels hydrating and smells nice. Skip it if your skin reacts to fragrance.

Key ingredients: Niacinamide 5%, peach extract 70% | Best for: Beginners, dry skin | Scent: Peach | My use: Tested in store

More Olive Young serums with niacinamide inside

While I was at the serum wall, I swatched other popular serums that also have niacinamide in the formula. One difference: in these, niacinamide is a supporting ingredient (around 6th on the ingredient list, % not disclosed), not the main star like in COSRX and Anua. These are quick in-store swatches, not long-term reviews, so I’m only telling you what’s on the label and what the texture looked like on my hand.

Avène Hyaluron Activ B3 Serum

The “B3” in the name is niacinamide (vitamin B3), paired with hyaluronic acid. But as the bottle itself says, this is really an anti-aging serum focused on lifting and firming, not a product made just for pores. On my hand it had a little thickness to it, and it felt like it would be great for deep hydration. Pick it if your main concern is firmness and dryness, with pores as a bonus.

Key ingredients: Niacinamide (vitamin B3), hyaluronic acid | Best for: Firmness and dryness

numbuzin No.3 Bifida Bakuchiol Zero Pore Serum

The label lists bifida and galactomyces ferments, bakuchiol (a plant-based retinol alternative) and niacinamide. The moment it went on, I could feel the hydration. It has a little bit of thickness to it, but it spreads really easily. The product description says makeup goes on well over it, and from how it felt on my hand, I believe it. This is the one I’d pick for mornings before makeup.

Key ingredients: Bifida and galactomyces ferments, bakuchiol, niacinamide | Best for: Mornings before makeup

MEDIHEAL Derma Serum PDRN Pore

PDRN, niacinamide, peptides and squalane. MEDIHEAL also makes this line as toner pads, and you can tell it’s one of the products they’re pushing hardest right now. It targets three things at once: pores, firmness and that glassy “결광” (gyeol-gwang, smooth-texture glow). The brand highlights its 99% purity PDRN, the ingredient Koreans know from “salmon DNA” skin boosters.

This was my favorite texture of the group. It’s slightly milky, not clear, and it absorbed almost instantly. Some of the other serums felt like they sat on top of my skin for a while. This one sank right in, so I think it would really cut down the wait before makeup.

Souvenir tip: Olive Young currently has a Seoul Edition set of this serum (with a refill and a Seoul luggage tag), which makes a nice gift to bring home.

Key ingredients: PDRN, niacinamide, peptides, squalane | Best for: Pores and glow, quick routines

medicube PDRN Pink Peptide Serum

The viral pink one (I found the Hangyodon character edition). This is the PDRN product medicube is pushing hardest right now, so much that they also sell sheet masks soaked in this same ampoule. medicube markets it for fading dark spots and blemishes. It has niacinamide and peptides in it too.

On my hand it was really moisturizing, a pink, jelly-like texture, and it smells nice. If you want a glow-and-hydration serum that’s pleasant to use every day, this is the fun one. If you’re sensitive to scent, keep that in mind.

Key ingredients: PDRN, niacinamide, peptides | Best for: Glow and hydration

Which niacinamide serum should you buy?

• Oily skin, big pores: COSRX 15. My pick.
• Dark spots or leftover acne marks: Anua 10 + TXA 4.
• Dry or sensitive-ish skin, or your first niacinamide ever: Anua Peach 70 (if fragrance is OK for you).

All three are easy to find at Olive Young stores in Seoul. Swatch them on the back of your hand like I did before you decide.

Pairing your serum with a toner pad? I tested 9 of those too in my Korean toner pad guide.

When serums aren’t enough

A serum can make pores look smaller and help marks fade, but it can’t change everything. Deep acne scars, stubborn melasma, or pores that are large because of skin structure usually need more than skincare. In Korea, that’s when people go to a 피부과 (pi-bu-gwa, dermatology clinic) for treatments like laser toning. I’m writing a separate guide on that soon.

Frequently asked questions

I’m a licensed esthetician in Seoul, not a doctor. This post is my personal experience and general information, not medical advice. If you have a skin condition, talk to a dermatologist. Prices and product lineups at Olive Young change often.