# COSRX Master Patch Basic

Hydrocolloid blemish patches, 36 ea, the original fit.

- Brand: COSRX
- Product: Master Patch Basic
- Price: $8.99
- Availability: Out of stock
- Size: 36ea
- Market: Korean market, the version sold in Korea
- Made in: Republic of Korea
- EAN (barcode): 8809598454736

## Key benefits

- Hydrocolloid absorbs fluid from the spot and turns visibly white as it works
- Covering the spot keeps fingers off it, which is half the battle
- A short material list with nothing to sensitize the skin around the spot
- Thin cut edges sit flat enough for day or night wear

## How it works

A hydrocolloid patch is a dressing: it covers one spot, takes up what the spot gives off, and keeps fingers and fabric away from it. This is the basic patch in COSRX's Master Patch range, the plain version with nothing worked into the material. It goes on last, on clean dry skin, because nothing sticks over a serum or a cream that has not absorbed. The middle turns white or cloudy while it is on, which is the fluid it has drawn up. One patch per spot, overnight, then a fresh one if the spot is still there.

## How to use

1. Press one Master Patch Basic onto clean, dry skin at the end of the evening routine.
2. Choose the size that covers the spot with a small margin, then press from the middle outward until the edges lie flat.
3. Nothing goes over it, and it holds best on bare skin, so let every leave-on layer absorb first.
4. One patch per spot per night. Do not press one onto damp skin or over a cream; it will lift within the hour.

## Ingredients

Cellulose Gum, Hydrogenated Poly(C6-20 Olefin), Polyisobutene, Styrene/Isoprene Copolymer

## FAQ

### What does the Master Patch Basic actually do?

This is COSRX's simplest hydrocolloid patch, a four-ingredient material list: cellulose gum, hydrogenated poly(C6-20 olefin), polyisobutene and styrene/isoprene copolymer. Cellulose gum is the absorbent core that pulls fluid from a blemish, while the other three form the flexible adhesive film around it. There's no named active ingredient added on top, just the dressing itself. Thirty-six patches ship per box for spot-by-spot use.

### Is this a safe pick for sensitive or reactive skin?

Fragrance, essential oil, denatured alcohol, silicone, parabens, sulfate surfactants, mineral oil and added colourant are all absent from this four-entry ingredient list. With only cellulose gum and three adhesive-film ingredients present, there is very little in the formula beyond the dressing material itself. That short a list is one of the more straightforward options for skin that reacts to actives, though any material touching skin, including an adhesive film, can still irritate in individual cases.

### Will this patch make a blemish disappear by morning?

The patch works by absorbing fluid out of a spot into the cellulose gum layer, which is why the center turns visibly white or cloudy as it fills. That's evidence the dressing is doing its job of drawing fluid and shielding the area, not evidence the blemish itself is gone underneath. Replacing a saturated patch, rather than expecting one overnight application to finish the process, is the realistic way to use it.

### Can I use this with a spot treatment or retinoid step?

No ingredient on this four-ingredient list overlaps with an active spot treatment or a retinoid, since the patch is purely an absorbent dressing. Applying a leave-on treatment to clean, dry skin first and letting it fully absorb before pressing the patch on keeps the two from sliding around on wet skin. The patch then sits over that spot rather than under it.

### How do I check that my Master Patch Basic is the authentic formula?

COSRX also verifies units directly: the batch number and expiration date on your box can be entered on the verification page at cosrx.com. Reading those two codes off your own packaging, rather than trusting a listing's word for it, is the actual verification.

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Page: https://korean-pharmacy.com/products/cosrx-master-patch-basic