Isntree
Hyper Vitamin C 23 Serum 20ml
Isntree Hyper Vitamin C 23 Serum is a 20ml serum with Ethyl Ascorbyl Ether, used after toner and before moisturizer, morning and evening.
No reviews yet- Ships from our California warehouse
- Duties prepaid
- Suited to
- Dehydrated skinSensitive skinDull, uneven tone
- Helps with
- Shoppers looking for Ethyl Ascorbyl Ether in a serumRoutines that want Ethyl Ascorbyl Ether and Adenosine in one stepFilling the serum step with a Korean-market formula
Sold out.
Tell us where to send it
One email, the moment this exact unit is back in stock. Not a newsletter and not a sequence, and your address comes off the list the second it is sent.
- Duties prepaid
- 30-day returns
- Free US shipping on orders of $100 or more
- Dispatched within 2 business days
How it works
The Hyper Vitamin C 23 Serum is a 20ml serum, used after toner and before moisturizer, morning and evening. The vitamin it is built around is Ethyl Ascorbyl Ether, named eighth on its own ingredient list. The same list carries Adenosine, Ascorbic Acid and Tocopherol, so the vitamin is not the only thing on it worth naming. How much of the Ethyl Ascorbyl Ether stays on the skin, and for how long, is decided by the serum format rather than by the list alone. Isntree sells this Ethyl Ascorbyl Ether serum in Korea, and this is that version.
Key benefits
- Ethyl Ascorbyl Ether, the vitamin this serum is built around
- Adenosine on the same list, an active
- Ascorbic Acid and Tocopherol on the same list, antioxidants
- Gardenia Florida Fruit Extract on the same list, a plant extract
- Polyglycerin-3 and Hydroxyethyl Urea further down the same list
- Panthenol further down the same list
Key actives
Ethyl Ascorbyl Ethervitamin
A vitamin C derivative with an ethyl group on the third position, the same molecule usually written 3-O-Ethyl Ascorbic Acid. The ether makes it far more stable in water than pure ascorbic acid. The name on the box points at it, and it is named eighth on this serum's own ingredient list.
Adenosineactive
Adenosine is a nucleoside that Korea's own cosmetic authority recognises as a wrinkle-care functional ingredient, which is why it appears on so many Korean lists at a low level. It is used for the look of fine lines and is stable and well tolerated. The panel names it twelfth on this serum's list, beside Ethyl Ascorbyl Ether.
Ascorbic Acidantioxidant
Ascorbic Acid is pure vitamin C, the most researched form and also the least stable: it needs a low pH and airtight packaging to stay active. It is an antioxidant used for the look of dullness and uneven tone. It is named second on this serum's list, alongside Ethyl Ascorbyl Ether.
Tocopherolantioxidant
Tocopherol is vitamin E. It is an oil-soluble antioxidant that protects the oils in a formula from going rancid and works on skin as an emollient, and it is regularly paired with vitamin C because each keeps the other going for longer. The panel names it seventeenth on this serum's list, beside Ethyl Ascorbyl Ether.
Gardenia Florida Fruit Extractplant extract
Gardenia Fruit Extract is the traditional East Asian yellow dye plant. In skincare it is used as an antioxidant extract, and it can tint a formula. The panel names it fifteenth on this serum's list, beside Ethyl Ascorbyl Ether.
Isntree Hyper Vitamin C 23 Serum 20ml
Where does this serum go in my routine?
After toner and before moisturizer, morning and evening. Anything thinner than a serum goes on before it, and anything richer goes on after. If you are adding it to a routine you already like, give it a week on its own first, so what you see is the Ethyl Ascorbyl Ether and not three changes at once.
What else is on the list besides Ethyl Ascorbyl Ether?
Adenosine, Ascorbic Acid and Tocopherol. The order they are printed in on this serum's panel is the order on the box, so you can see where Ethyl Ascorbyl Ether sits relative to them. Further down the same panel: Gardenia Florida Fruit Extract, Polyglycerin-3 and Hydroxyethyl Urea.
- Ships from
- California
Duties are prepaid. Nothing is owed at delivery. Returns are accepted for 30 days, by mail.
Orders ship from our California warehouse, dispatched within 2 business days, and arrive in 3 to 5 days. Shipping is free on orders of $100 or more.
We split shipments free, so one out-of-stock item never holds up the rest of your order.
Where this unit came from
- 1Seoul
Bought as Korean-market stock - 2Customs
Duty paid by us before it enters the US - 3California
Ships domestically, no international leg
We stock the version of a formula that is sold in Korea, not the release a brand prepares for another market under the same name.
Every unit keeps its original barcode and batch code intact, so the unit in your hands can be checked against the brand’s own records.
Import duties are paid by us before the parcel reaches you, so nothing is owed at the door, and returns run for 30 days.
Every claim on this page traces to the unit in the box, the barcode, the batch code and the price you can read for yourself.
Payment and security
We accept
How to use
- Use the Hyper Vitamin C 23 Serum after toner and before moisturizer, morning and evening.
- Three or four drops covers the whole face. Press it in with flat palms instead of rubbing it around.
- Toner first so the surface is damp, then this, then about a minute before your moisturizer goes over the top.
- Twice a day, every day. Do not stack it with a second serum of the same kind; two hydrating serums in one routine do the work of one.
Worth knowing
- Patch test this serum on a small area and wait a day before using it more widely, especially with Ethyl Ascorbyl Ether on the list.
- Introduce this serum on its own for the first week, so anything your skin does is traceable to the Ethyl Ascorbyl Ether rather than to three changes at once.
Reviews
No reviews yet. Tell us how much you love the product!
Write Reviews (opens in a new tab)Isntree, Korean-market original
The Original Korean Formula serum from Isntree, 20ml formulated with Ethyl Ascorbyl Ether and Adenosine, held in the United States and shipped domestically.
Verify your unit when it arrives
Verify your unit when it arrives
Korean-market stock with the original barcode and batch code intact, exactly as it left Korea.
Match the batch code on the box against the code printed on the bottle or tube itself; the two are stamped separately and should agree.
On the unit itself
- The Korean-market barcode, unaltered from the retail package.
- The manufacturer’s batch code, exactly as the maker printed it.
정품Genuine article, Korean-market stock
What professionals say
What professionals say
What skin-care professionals say about the key actives in this formula, quoted from the medical sources linked beside each.
Using topical vitamin C can result in less cell damage and better-looking skin.
Melissa Piliang, MDDermatologist, Cleveland Clinic People with dry, flaky skin are more likely to see a benefit from using vitamin E because it enhances moisturization.
Amy Kassouf, MDDermatologist, Cleveland Clinic
Ask an AI assistant about this product
Ask an AI assistant about this product
Opens ChatGPT, Perplexity or Claude in a new tab with the question prefilled. Claude asks you to sign in first.