COSRX
The Niacinamide 15 Serum
A pore-refining serum led by niacinamide; this bottle's own list does not declare a percentage, so the 15 in the name is not claimed here.
No reviews yet- Ships from our California warehouse
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- Suited to
- DryDehydratedSensitiveCompromised barrier
- Helps with
- DehydrationBarrier weaknessEarly environmental damageUneven tone and dullness
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- 30-day returns
- Free US shipping on orders of $100 or more
- Dispatched within 2 business days
How it works
A niacinamide serum is bought for how the surface looks: tone, shine, and the size pores appear to be. This is the niacinamide step in COSRX's line, a short, thin formula that goes on after toner and before moisturizer. Skin that turns shiny by midday and reads uneven in tone is the case it fits, and it is a daily step rather than an occasional one. Niacinamide is one of the few actives that sits happily in both the morning and the evening routine. Twice a day, and it layers under anything else already in place.
Key benefits
- Niacinamide is third on the ingredient list.
- Zinc PCA and acetyl glucosamine support the pore-refining focus.
- Trehalose and allantoin round out the hydrating, calming base.
- No percentage is declared on this bottle's own list, so none is claimed.
Key actives
Niacinamide
third on the list, for a clearer, more even look
Zinc PCA
helps balance the look of oily skin
Acetyl Glucosamine
supports niacinamide's brightening effect
COSRX The Niacinamide 15 Serum
What does The Niacinamide 15 Serum actually do for the skin?
Niacinamide sits third on the list, right behind water and pentylene glycol, with Zinc PCA and Acetyl Glucosamine following close behind. That order places niacinamide near the front of a short, pore-focused formula, with trehalose and allantoin further down to round out the hydrating, calming base. The combination targets pore appearance and tone rather than acting as a broad hydrating serum.
Is this serum suitable for oily, pore-prone skin?
The list has no fragrance, no essential oil, no added silicone, no paraben, and no mineral oil. That profile suits oily and pore-prone skin looking for a lightweight, fragrance-free niacinamide serum. This bottle's own list does not declare a percentage for niacinamide, so despite the name, no specific strength figure is claimed here.
How long before pores or tone look different with regular use?
Niacinamide and zinc PCA both work toward a clearer, more even look with sustained daily application rather than a single dose. Visible pore appearance and oiliness tend to shift gradually across several weeks of consistent morning and evening use, not immediately. Applying it inconsistently will slow that pace considerably compared with a steady routine.
Can I layer this serum with a retinoid or exfoliating acid?
This list does not include a retinoid or an exfoliating acid, so it is built as a standalone niacinamide step rather than a base formulated to carry either. Applying it after toner and letting it absorb before a separate treatment step is a reasonable order, but whether it pairs well with a specific acid or retinoid depends on that other product's own formula. Introduce anything new slowly and watch for irritation.
How do I verify this bottle is the authentic Korean-market Niacinamide 15 Serum?
The bottle carries its original Korean-market barcode, 8809598454637, unaltered from the release sold in Korea. COSRX verifies its own units directly rather than leaving that job to a reseller: enter the batch number and expiration date printed on your bottle into the verification page on cosrx.com. Reading those figures off your own bottle, not off a listing photo, is what actually confirms it.
- Ships from
- California
Duties are prepaid. Nothing is owed at delivery. Returns are accepted for 30 days, by mail.
Orders ship from our California warehouse, dispatched within 2 business days, and arrive in 3 to 5 days. Shipping is free on orders of $100 or more.
We split shipments free, so one out-of-stock item never holds up the rest of your order.
Where this unit came from
- 1Seoul
Bought as Korean-market stock - 2Customs
Duty paid by us before it enters the US - 3California
Ships domestically, no international leg
We stock the version of a formula that is sold in Korea, not the release a brand prepares for another market under the same name.
Every unit keeps its original barcode and batch code intact, so the unit in your hands can be checked against the brand’s own records.
Import duties are paid by us before the parcel reaches you, so nothing is owed at the door, and returns run for 30 days.
Every claim on this page traces to the unit in the box, the barcode, the batch code and the price you can read for yourself.
Payment and security
We accept
How to use
- Use the Niacinamide 15 Serum after toner and before moisturizer, morning and evening.
- Three or four drops covers the face. Press it in rather than rubbing it across the skin.
- Toner first, this second, then moisturizer, and sunscreen last in the morning.
- Twice a day, every day. Do not layer it with a second niacinamide product; one step of it is enough in a routine.
Reviews
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COSRX, Korean-market original
Niacinamide Serum, 20 ml, with Zinc PCA.
Verify your unit when it arrives
Verify your unit when it arrives
Korean-market stock with the original barcode and batch code intact, exactly as it left Korea.
COSRX verifies units itself. Find the verification page on cosrx.com and enter the batch number and expiration date printed on your unit. Read them off the package rather than from us, which is the point.
Source: COSRX FAQ
On the unit itself
- The Korean-market barcode, unaltered from the retail package.
- The manufacturer’s batch code, exactly as the maker printed it.
정품Genuine article, Korean-market stock
What professionals say
What professionals say
What skin-care professionals say about skin care, quoted from the medical sources linked beside each.
Pretty much every step of a Korean skin care routine is going to have some component of hydration.
Alok Vij, MDDermatologist, Cleveland Clinic Niacinamide helps reduce the appearance of pores in a few ways. By strengthening the skin barrier and improving elasticity, pores appear less noticeable and more even.
Ashlyn YankeAesthetician, Cleveland Clinic
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