IOPE
Vitamin C Expert 40% Mask Concentrate 15g
Ascorbic Acid is the first entry on this list, in an anhydrous silicone and ester base with no water in the top ten, alongside Resveratrol and Nicotinamide Mononucleotide. 15 g, used once or twice a week.
No reviews yet15 g
$58.33 per 10 g
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- Dehydrated skinSkin that has lost bounceDull, uneven tone
- Helps with
- Shoppers looking for Ascorbic Acid in a sheet maskRoutines that want Ascorbic Acid and Nicotinamide Mononucleotide in one stepFilling the sheet mask step with a Korean-market formulaAnyone who wants the Ascorbic Acid sheet mask sold on Korean shelves
In stock. Arrives in 3 to 7 business days
We accept
You’re $100.00 away from free US shipping.
- 30-day returns
- Free US shipping on orders of $100 or more
- Tracked delivery to your door
How it works
The Vitamin C Expert 40% Mask Concentrate is a 15g sheet mask, used after toner, in place of your serum step, in the evening. The antioxidant it is built around is Ascorbic Acid, named first on its own ingredient list. The same list carries Nicotinamide Mononucleotide, Thymol Trimethoxycinnamate and Resveratrol, so the antioxidant is not the only thing on it worth naming. How much of the Ascorbic Acid stays on the skin, and for how long, is decided by the sheet mask format rather than by the list alone. This is the Original Korean Formula, the sheet mask IOPE sells in Korea, Ascorbic Acid and all.
Key benefits
- Ascorbic Acid, the antioxidant this sheet mask is built around
- Nicotinamide Mononucleotide on the same list, an active
- Thymol Trimethoxycinnamate and Resveratrol on the same list, antioxidants
- Glycine Max (Soybean) Polypeptide on the same list, a protein
- Hydrogenated Polyisobutene and Cetyl Ethylhexanoate further down the same list
- Triethylhexanoin and Polyglyceryl-3 further down the same list
Inside the formula
Inside the formula
Where does this sheet mask go in my routine?
After toner, in place of your serum step, in the evening. Toner goes on before it, and the rest of the routine goes on after you take the sheet mask off. 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 Ascorbic Acid and not three changes at once.
Is this the Korean-market sheet mask or a US version?
The Korean-market one, Ascorbic Acid and all. We match this sheet mask to its Korean barcode before it reaches the shelf, which is the check that tells you which market release you are holding.
What else is on the list besides Ascorbic Acid?
Nicotinamide Mononucleotide, Thymol Trimethoxycinnamate and Resveratrol. The order they are printed in on this sheet mask's panel is the order on the box, so you can see where Ascorbic Acid sits relative to them. Further down the same panel: Glycine Max (Soybean) Polypeptide, Hydrogenated Polyisobutene and Cetyl Ethylhexanoate.
Not on the ingredient list below: fragrance or parfum, denatured or SD alcohol, essential oils, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (20): Ascorbic Acid, Phenyl Trimethicone, Silica Dimethyl Silylate, Hydrogenated Polyisobutene, Caprylic/Capric Triglyceride, Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer, Caprylyl Methicone, C12-15 Alkyl Benzoate, Cetyl Ethylhexanoate, Hydrogenated Castor Oil Dimer Dilinoleate, Triethylhexanoin, Polyglyceryl-4 Diisostearate/Polyhydroxystearate/Sebacate, Diisostearoyl Polyglyceryl-3 Dimer Dilinoleate, Polymethyl Methacrylate, Thymol Trimethoxycinnamate, Kojyl Methylenedioxycinnamate, Nicotinamide Mononucleotide, Methyl Methacrylate/Acrylonitrile Copolymer, Resveratrol, Glycine Max (Soybean) Polypeptide
Ingredient list read from iope.com on 30 August 2026.
16 of 20 explained
- Ascorbic Acid antioxidant
- 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.
- Phenyl Trimethicone silicone
- Phenyl Trimethicone is a silicone with a higher refractive index than most, so it adds visible gloss as well as slip. It is common in glow and lip textures.
- Silica Dimethyl Silylate absorbent
- Silica Dimethyl Silylate is silica with a silicone surface coating. It absorbs oil, thickens and stops powders clumping.
- Hydrogenated Polyisobutene emollient
- Hydrogenated Polyisobutene is a stabilised synthetic hydrocarbon used in place of mineral oil. It is an emollient that leaves a smooth, cushioned film.
- Caprylic/Capric Triglyceride emollient
- Caprylic/Capric Triglyceride is the light fraction of coconut oil, with the heavy parts removed. It is the workhorse emollient of modern formulas: it softens skin, dissolves oil-soluble actives and absorbs without the greasy weight of a whole plant oil.
- Vinyl Dimethicone/Methicone Silsesquioxane Crosspolymer silicone
- A silicone elastomer powder. It changes how light falls on skin so texture looks softer, absorbs a little oil, and leaves a dry velvet finish.
- Caprylyl Methicone silicone
- Caprylyl Methicone is a silicone with a fatty tail, so it mixes with plant oils as well as with silicones. It gives a dry slip and helps disperse powders.
- C12-15 Alkyl Benzoate emollient
- C12-15 Alkyl Benzoate is a light ester emollient and solvent. It gives a silky finish, dissolves pigments and UV filters, and mildly discourages microbial growth.
- Cetyl Ethylhexanoate emollient
- Cetyl Ethylhexanoate is a synthetic ester used as a dry-feeling emollient. It spreads easily, leaves a silky rather than oily finish, and helps disperse pigments and UV filters evenly.
- Triethylhexanoin emollient
- Triethylhexanoin is a light ester emollient that softens skin and disperses pigment. It absorbs cleanly and is often used to thin a heavy oil phase.
- Polyglyceryl-4 Diisostearate/Polyhydroxystearate/Sebacate emulsifier
- This is a water-in-oil emulsifier used in rich creams and cleansing balms, and it disperses pigment well.
- Polymethyl Methacrylate absorbent
- Polymethyl Methacrylate is an acrylic polymer used as fine spheres. They give a smooth, powdery slip and blur the look of surface texture.
4 more explained
- Thymol Trimethoxycinnamate antioxidant
- Thymol, the phenol from thyme, joined to a cinnamic acid ester. The ester form is oil soluble and stable, and it is used as an antioxidant.
- Nicotinamide Mononucleotide active
- Nicotinamide Mononucleotide is a nucleotide built from vitamin B3 and a sugar phosphate. Korean formulas use it as a conditioning active, usually alongside niacinamide itself.
- Resveratrol antioxidant
- Resveratrol is an antioxidant from grape skin and Japanese knotweed. It is used for the look of dullness and is often paired with ferulic acid, which keeps it stable.
- Glycine Max (Soybean) Polypeptide protein
- Soy protein cut into shorter polypeptide chains. The smaller chains dissolve in water and are used as a conditioning protein that leaves a smooth film.
- Market
- Korean market, the version sold in Korea
- EAN (barcode)
- 8809925161016
- Made in
- Republic of Korea
- Volume
- 15 g
- Category
- Serum & Ampoule
- Actives
- Vitamin C
- Ships from
- California or Korea
Orders ship from California or direct from Korea with tracked delivery to your door, and both routes carry the same Korean-market release. Shipping is free on orders of $100 or more. Returns are accepted for 30 days, by mail.
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 - 2Barcode
Listed against the Korean barcode on its box - 3California or Korea
Ships to you from either, as the same Korean-market release
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. The barcode in the specification above is the Korean-market one and it is printed on the box you receive.
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.
Every order ships from California or direct from Korea, 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.
How to use
- After cleansing, 1 to 2 times a week.
- Apply as directed, avoiding the eye area.
- Follow the product's own rinse-off or leave-on timing.
Worth knowing
- Patch test this sheet mask on a small area and wait a day before using it more widely, especially with Ascorbic Acid on the list.
- Introduce this sheet mask on its own for the first week, so anything your skin does is traceable to the Ascorbic Acid rather than to three changes at once.
Complete the routine
- This itemIOPE Vitamin C Expert 40% Mask Concentrate 15g$87.50
- Seal the routine in as the last stepIOPE SUPER VITAL EMULSION 150ml$87.50
- The treatment step of this routineIOPE RETINOL RETI-JECTION SERUM 30ml$100.00
Total for 3 items$275.00
Reviews
No reviews yet. Tell us how much you love the product!
Write a reviewWrite a review
IOPE Vitamin C Expert 40% Mask Concentrate 15g
How it felt, how your skin took it, what you layer it with. Straight answers help the next person choose.
We’re on gram!
Creators trying on authentic Korean skincare routines and products from us.
Rating a shelf of Dr. Althea products one by one.
Jasmine Loo · YouTube
Two hydrating serums side by side, IUNIK and Dr. Althea.
Kristin · YouTube
A walk through the Dr. Althea serum lineup and who each one suits.
auraofmahmuda · YouTube
A blunt first take on the Dr. Althea range.
Lexi Chang · YouTube
A first look at the viral 345 Relief Cream before buying.
Shelley Nayak · YouTube
A first try of the Dr. Althea serum on camera.
Hannah Ziad · YouTube
IOPE, Korean-market original
The Original Korean Formula sheet mask from IOPE, 15g formulated with Ascorbic Acid and Nicotinamide Mononucleotide, shipped from California or direct from Korea.
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.
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 skin care, quoted from the medical sources linked beside each.
Your skin barrier is basically your outer layer of the skin.
Melissa Piliang, MDDermatologist, Cleveland Clinic Pretty much every step of a Korean skin care routine is going to have some component of hydration.
Alok Vij, 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.