# COSRX Niacinamide 15 vs Poreless Power Liquid

**Question answered:** Should I choose COSRX The Niacinamide 15 Serum or Two in One Poreless Power Liquid?

**Short answer:** Choose The Niacinamide 15 Serum if you want a non-exfoliating serum for oil and the look of pores, with 15% niacinamide and zinc PCA. Choose Two in One Poreless Power Liquid if you want a leave-on BHA step with betaine salicylate and willow bark water, and you don't mind a cooling mint ingredient. Both are sold as fragrance free.

By Nora Ellison. Published 2026-10-29. Data is taken from manufacturer labels; the products have not been tested.

## What this means for you

### Start with what you notice

Both are COSRX products for oily skin and the look of pores, but they work differently. One is a vitamin serum; the other is an exfoliating liquid.

### The ingredient names, translated

Niacinamide is a form of vitamin B3 used for oil and uneven tone. Betaine salicylate is related to salicylic acid, an exfoliant that works inside pores. The Niacinamide serum adds acetyl glucosamine and zinc PCA. The Poreless liquid adds panthenol, allantoin, sodium hyaluronate, menthyl lactate and mint extract.

### How to decide

- Want help with oil without exfoliating? Niacinamide 15 Serum.
- Clogged pores and blackheads? Two in One Poreless Power Liquid.
- Sensitive to mint or cooling ingredients? Niacinamide 15 Serum.

### What to expect

Both may make pores look smaller and skin less shiny over several weeks of daily use. Pore size itself doesn't change much. We haven't tested either product.

General guidance, not a test of these products: [AAD: how to safely exfoliate at home](https://www.aad.org/public/everyday-care/skin-care-secrets/routine/safely-exfoliate-at-home); [DermNet: comedones](https://dermnetnz.org/topics/comedones). Each product's label source is linked on its product page.

## Niacinamide serum vs BHA liquid

[COSRX The Niacinamide 15 Serum](product:cosrx-the-niacinamide-15-serum) is a 20 mL serum with 15% [niacinamide](/ingredients/niacinamide/). It adds [acetyl glucosamine](/ingredients/acetyl-glucosamine/), [zinc PCA](/ingredients/zinc-pca/), [trehalose](/ingredients/trehalose/) and [allantoin](/ingredients/allantoin/). COSRX says to follow with SPF 30 or higher in the morning.

[COSRX Two in One Poreless Power Liquid](product:cosrx-two-in-one-poreless-power-liquid) starts with [willow bark water](/ingredients/salix-alba-willow-bark-water/) and lists [betaine salicylate](/ingredients/betaine-salicylate/), [panthenol](/ingredients/panthenol/), sodium hyaluronate, menthyl lactate and mint extract. COSRX says it can be wiped on with a cotton pad or left on oily areas for five to ten minutes.

> **Skin Realist check:** pores don't open and close. What changes is how clogged and shiny they look.

## Label differences worth knowing

Only the Poreless liquid exfoliates, so it's the one to space out from other acids and retinoids. See our [blackheads vs sebaceous filaments guide](/articles/blackheads-vs-sebaceous-filaments/) and our [COSRX BHA Blackhead vs Poreless Power Liquid comparison](/comparisons/cosrx-bha-blackhead-liquid-vs-poreless-power-liquid/).

## Manufacturer sources

- [COSRX The Niacinamide 15 Serum](https://www.cosrx.com/products/the-niacinamide-15-serum-%EB%B2%88%EB%93%A4)
- [COSRX Two in One Poreless Power Liquid](https://www.cosrx.com/products/two-in-one-poreless-power-liquid)

Sources and label-check dates are recorded on the product pages.

| Product | Price | Key ingredients | Skin types | Fragrance | Flagged ingredients | Size | Source | Buy |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| [COSRX The Niacinamide 15 Serum](https://dermalguide.com/products/cosrx-the-niacinamide-15-serum/) | $20.00 at [Stylevana](https://www.awin1.com/pclick.php?p=43018982649&a=3132625&m=90791) (affiliate), checked 2026-10-29 07:35 UTC | Niacinamide 15% | Brand doesn't say | Marketed as fragrance free | No flags recorded; not a safety guarantee | 20 ml | [Manufacturer label](https://www.cosrx.com/products/the-niacinamide-15-serum-%EB%B2%88%EB%93%A4), checked 2026-10-10 | [Amazon (affiliate)](https://amzn.to/4yL1sKV) |
| [COSRX Two in One Poreless Power Liquid](https://dermalguide.com/products/cosrx-two-in-one-poreless-power-liquid/) | $20.00 at [Stylevana](https://www.awin1.com/pclick.php?p=43018980486&a=3132625&m=90791) (affiliate), checked 2026-10-29 07:35 UTC | Betaine Salicylate (BHA) | Brand doesn't say | Marketed as fragrance free | Menthyl Lactate, Mentha Haplocalix Extract | Brand doesn't list it | [Manufacturer label](https://www.cosrx.com/products/two-in-one-poreless-power-liquid), checked 2026-10-10 | [Amazon (affiliate)](https://amzn.to/4yEUSp5) |

## Which to choose

Consider COSRX The Niacinamide 15 Serum when: You want oil control without an exfoliant; You also care about post-blemish marks.

Consider COSRX Two in One Poreless Power Liquid when: Clogged pores and blackheads are your main concern; You want a toner-style BHA step.


## Questions

### Can I use both?

Many people pair a BHA with niacinamide. Start one at a time and use the liquid first, then the serum, so you can tell which one your skin reacts to.

### Is 15% niacinamide a lot?

It's higher than many niacinamide serums. Some people get flushing or stinging at higher strengths, so patch test first.

### Which has a cooling ingredient?

Two in One Poreless Power Liquid lists menthyl lactate and mint extract. The Niacinamide serum lists neither.