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.

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.