COSRX

COSRX Niacinamide 15% Serum.

Serums

About this product

A lightweight serum featuring 15% niacinamide, designed to reduce redness, control excess oil, and support clearer skin.

Full ingredients

Water, Pentylene Glycol, Niacinamide (15%), Butylene Glycol, Acetyl Glucosamine, 1,2-Hexanediol, Zinc Pca, Trehalose, Xanthan Gum, Pullulan, Allantoin, Ethylhexylglycerin, Sodium Phytate, Citric Acid, Tocopherol

Guru Score

78%

Yay

Early verdict · Few reviews so far

What the gurus are saying

This serum's lighter texture suits oily skin well, and the 15% niacinamide concentration is strong enough to calm redness and manage oil without pushing into the higher percentages that can trigger breakouts or irritation in some people. Starting here and adjusting upward is a sensible approach if niacinamide benefits your skin.

Synthesized from 2 expert reviews · most recent take February 2025

What they liked

Light texture suits oily skin
Gentle enough to start with

What they flagged

Niacinamide concentration unremarkable

Best for

Oily skin Acne-prone skin

Type

SerumsDrops & dropper

Key actives

NiacinamideVitamin E

Formula notes

Fragrance-freeNo drying alcohol

Where to buy

Ulta → Amazon → Google → iHerb →

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What the gurus are saying.

Every take we've logged from this product's reviews across YouTube. Click any row to watch the moment they said it.

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CYoung

95k subs

✓Yay

"If you want more niacinamide, COSRX has a niacinamide serum at fifteen percent, the texture is even lighter, so for oily skin it's no problem, this one can be the better pick."

All 2 takes from CYoung

Viral Korean Serums Tier Lists | Ranked and Reviewed

"Some people say they're not satisfied because the niacinamide percentage is low, but careful, more isn't always better, higher niacinamide concentrations can cause breakouts and inflammation, so start with a low percentage and work up. This one is just so so, ninety percent of the cosmetics I grab have niacinamide in them anyway, so it's not a C, but for anyone who wants it, this is a B."

TikTok viral skincare, worth the HYPE? My Very HONEST REVIEW | WATCH BEFORE YOU BUY!!!

"If you want more niacinamide, COSRX has a niacinamide serum at fifteen percent, the texture is even lighter, so for oily skin it's no problem, this one can be the better pick."

Nipun Kapur

412k subs

✓Yay

"The COSRX one is a lot more gentle. [...] If you start with a five percent or start with a ten percent that's absolutely fine. To beat texture or to beat any skin care problem you've got to be consistent, that is the key. You can switch to a higher concentration."

What the evidence says.

Independent of what the gurus think, this is what the published research supports about the main active ingredients here.

Niacinamide

Niacinamide has evidence behind it for redness, uneven tone and supporting the skin barrier, and it is usually well tolerated even by skin that reacts to most things.

Source: DermNet

Humectants and emollients

Ingredients like these draw water into the surface layers and slow how fast it leaves. The evidence is for comfort, softness and hydration rather than for changing the structure of the skin.

Source: DermNet

Vitamin E

Vitamin E is an antioxidant, and it is often in a formula to keep the other ingredients stable rather than as the active itself. It pairs well with vitamin C, though on its own the evidence for visible change is limited.

Source: NIH, National Library of Medicine

Frequently asked.

What is COSRX Niacinamide 15% Serum?

A lightweight serum featuring 15% niacinamide, designed to reduce redness, control excess oil, and support clearer skin.

Is COSRX Niacinamide 15% Serum worth it?

Yes. All 2 gurus who reviewed it give it their stamp of approval, for a Guru Score of 78%.

What is COSRX Niacinamide 15% Serum's Guru Score?

COSRX Niacinamide 15% Serum holds a Guru Score of 78%. That is our read on how warmly the experts talk about it, based on the verdicts of 2 expert reviewers we have collected.