Where does this go in my routine, and how much should I apply?

After toner, apply one drop to your forehead and one to each cheek. Gently spread and pat it in, then finish with cream.

What should I do with the separate dropper and gas-release cap?

Before your first use, twist off the gas-release cap and attach the separately packaged dropper. The original cap allows naturally produced gas to escape while limiting air re-entry before opening.

How often should I use it if I am new to high-concentration vitamin C?

Begin once daily. Move to morning and evening only after your skin has adjusted; the regular directions allow once- or twice-daily use.

Can I use it in the morning?

Yes. It can be used in the morning or at night. For daytime use, finish with SPF 30 or higher.

Does this vitamin C serum need refrigeration, and how long should I keep it after opening?

Store the unopened bottle upright at 3–10°C and keep it away from heat and direct sunlight. Refrigerate it when you will not use it daily, close the cap after each use and use it within three months of opening.

Which skin types and concerns is it intended for?

It is intended for all skin types, with dullness, uneven texture and uneven skin tone as its primary target concerns.

What does the serum feel like, and does it leave a sticky finish?

The oil-free base is lightweight and quick-absorbing. Finish feedback is mixed, however, and some shoppers do notice stickiness.

Does the formula contain fragrance?

Yes. The current ingredient declaration includes fragrance/parfum and limonene.

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IOPE

Vitamin C Expert 25% Antioxidant Toning Serum

What it is: A 25% pure vitamin C serum that targets dullness, uneven tone and rough texture for a brighter, firmer and more radiant look.

25% pure vitamin C
Radiance, tone and firmness care
0.2% PHA texture care
Vitamin C stability support

Net weight: 23 mL

Vitamin C Expert 25% Antioxidant Toning Serum

23ml ·$43.99 USD

25% pure vitamin C

Radiance, tone and firmness care

0.2% PHA texture care

Vitamin C stability support

Main active: No primary active
Intensity: Supportive

PRODUCT DETAILS

Hello, radiance. This 25% pure vitamin C serum is made for dullness, uneven tone and rough texture. The finished formula helps visibly brighten, firm and smooth rough-looking skin, bringing more clarity and glow to your routine.

At its center is ascorbic acid, paired with a five-antioxidant complex of glutathione, ferulic acid and three vitamin C derivatives. Together, they support antioxidant care, while the complex and a low-water system help maintain formula stability and antioxidant potency. The gas-release cap also limits air re-entry before you open the bottle.

For texture, 0.2% PHA adds dedicated smoothing care. The formula has a lightweight, quick-absorbing base, although finish feedback is mixed and some shoppers notice stickiness. After four weeks, the serum supports improved hydration and a more refined look to visible pores.

It is suitable for all skin types and can be used in the morning or at night. The formula contains fragrance and limonene, which is helpful to know if scent is part of how you choose your skincare.

Learn more

GOES WELL WITH

100 Reedle Shot Stick Pouch$8.09 USD

1025 Dokdo Eye Cream$22.99 USD

1025 Dokdo Sleeping Pack$15.99 USD

1025 Dokdo Sun Cream$18.99 USD

1025 Dokdo Cream$24.99 USD

1025 Dokdo Pad$20.99 USD

1025 Dokdo Cleanser$11.99 USD

1025 Dokdo Lotion$14.99 USD

Focused care for visible radiance, tone, texture, firmness, hydration and the look of pores.

Brighter, more radiant look
More even-looking tone
Smoother-looking texture
Firmer-looking skin
Measured hydration support
More refined-looking pores

Key Ingredients

Seven dry amber, apricot, lavender and celadon relief rays spread diagonally across one warm-ivory matte plaster surface beside a tiny coral point.

Vitamin C

An antioxidant ingredient family that can help brighten uneven-looking tone and soften visible dullness.

Five-Antioxidant Complex

Glutathione, ferulic acid and three vitamin C derivatives support antioxidant care and help maintain antioxidant potency in the formula.

Gluconolactone

A gentle exfoliating PHA that helps smooth skin texture while attracting moisture.

Panthenol

Pro-vitamin B5 that helps skin hold moisture and feel softer and more comfortable.

Real Results

-33.2%Reduction in measured pore area after four weeks¹
+20.1%Improvement in skin hydration after four weeks²
-25.5%Reduction in measured pore count after four weeks¹
-18.1%Reduction in measured pore depth after four weeks¹

View all 20 real results

+11.3%

Front view of the silver-gray dropper bottle on a clean white background.

Concerns & Benefits

Your Concerns

1
Dullness
When your complexion looks dull and short on radiance.
2
Uneven Skin Tone
When your tone looks less even from one area to another.

How To Use

1Before your first use, twist off the gas-release cap and attach the separately packaged dropper.
2After toner, apply to clean, well-hydrated skin: dispense one drop on your forehead and one on each cheek.
3Gently spread and pat the serum into your skin. Leave it on, then apply cream over it.
4Use once or twice daily. If you are new to high-concentration vitamin C, begin once daily and move to morning and evening only after your skin has adjusted.
5When applying it during the day, finish with SPF 30 or higher.

Dropper bottle standing upright on a gray pedestal.

Frequently asked questions

Is this a serum or an ampoule?

It is sold internationally as a serum and in Korea as a toning ampoule. Both names refer to the 23 mL treatment used at the serum or ampoule step.

Keep learning

Customer reviews

Frequently Bought Together

Buy these products together

This itemVitamin C Expert 25% Antioxidant Toning Serum$43.99 USD

100 Reedle Shot Stick Pouch$8.09 USD

1025 Dokdo Eye Cream$22.99 USD

Total price: $75.07 USD

This itemVitamin C Expert 25% Antioxidant Toning Serum$43.99 USD

100 Reedle Shot Stick Pouch$8.09 USD

1025 Dokdo Eye Cream$22.99 USD

Total price: $75.07 USD

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IOPE Vitamin C Expert 25% Antioxidant Toning Serum

IOPE

Vitamin C Expert 25% Antioxidant Toning Serum

What it is: A 25% pure vitamin C serum that targets dullness, uneven tone and rough texture for a brighter, firmer and more radiant look.

25% pure vitamin C
Radiance, tone and firmness care
0.2% PHA texture care
Vitamin C stability support

Net weight: 23 mL

Vitamin C Expert 25% Antioxidant Toning Serum

23ml ·$43.99 USD

25% pure vitamin C

Radiance, tone and firmness care

0.2% PHA texture care

Vitamin C stability support

Main active: No primary active
Intensity: Supportive

PRODUCT DETAILS

It is suitable for all skin types and can be used in the morning or at night. The formula contains fragrance and limonene, which is helpful to know if scent is part of how you choose your skincare.

Learn more

GOES WELL WITH

100 Reedle Shot Stick Pouch$8.09 USD

1025 Dokdo Eye Cream$22.99 USD

1025 Dokdo Sleeping Pack$15.99 USD

1025 Dokdo Sun Cream$18.99 USD

1025 Dokdo Cream$24.99 USD

1025 Dokdo Pad$20.99 USD

1025 Dokdo Cleanser$11.99 USD

1025 Dokdo Lotion$14.99 USD

Focused care for visible radiance, tone, texture, firmness, hydration and the look of pores.

Brighter, more radiant look
More even-looking tone
Smoother-looking texture
Firmer-looking skin
Measured hydration support
More refined-looking pores