Vitamin C in Korean Skincare: 3 Derivatives the MFDS Codex Lists

Korea's functional cosmetics codex lists three vitamin C derivatives as whitening ingredients, and plain vitamin C (ascorbic acid) is not one of them. The three are ascorbyl glucoside, ascorbyl tetraisopalmitate and ethyl ascorbyl ether, all in the whitening annex published by the Ministry of Food and Drug Safety (MFDS). Ascorbic acid itself shows up in that annex only as an impurity: raw ascorbyl glucoside may contain no more than 0.1% free ascorbic acid.

The page relies on two Korean legal texts. One is the MFDS notice "Standards and Test Methods for Functional Cosmetics" (기능성화장품 기준 및 시험방법), Notice No. 2025-89 as amended on 16 December 2025, which gives itself the English name Korean Functional Cosmetics Codex (KFCC). The other is Article 2 of the Enforcement Rule of the Cosmetics Act. Both were read in Korean from the annex files of the notice, check date 12 October 2026. Korean statutes and notices are uncopyrighted works (Copyright Act, Article 7), so the legal wording is quoted. No products are named or ranked.

Which vitamin C ingredients does the Korean codex list?

Annex 2 of the codex, 피부의 미백에 도움을 주는 기능성화장품 각조 ("monographs for functional cosmetics that help whiten the skin"), contains eight raw-ingredient monographs. Three are vitamin C derivatives:

• Ascorbyl glucoside (아스코빌글루코사이드): ascorbic acid bound to glucose; the codex prints its other name as ascorbic acid 2-glucoside
• Ascorbyl tetraisopalmitate (아스코빌테트라이소팔미테이트): described by the codex as mainly the tetraester of ascorbic acid and isopalmitic acid
• Ethyl ascorbyl ether (에칠아스코빌에텔): the codex's other name is 3-O-ethyl ascorbate

The other five whitening monographs are niacinamide, broussonetia extract, arbutin, alpha-bisabolol and oil soluble licorice extract.

Why is plain ascorbic acid missing?

The annex files read for this page have no monograph titled ascorbic acid. Ascorbic acid appears in two places only: as part of the derivatives' descriptions, and as a purity test inside the ascorbyl glucoside monograph, where free ascorbic acid is capped at 0.1%. The MFDS codex does not explain why it lists derivatives rather than the parent vitamin, and this page will not supply a reason the text does not give.

Remember what the codex is. Rule 1 of its general annex says it sets the range in which a company applying for functional cosmetic review may be excused from submitting its own standards and test methods. Not having a monograph here does not by itself mean an ingredient is banned from cosmetics. It means the codex has not prewritten its tests for the whitening type.

How do the three derivatives compare?

Values are copied from each monograph; the English is ours. The codex prints ascorbyl glucoside's English title as "Ascobyl Glucoside", an obvious typo corrected here.

The figures that follow are as printed in the MFDS Korean Functional Cosmetics Codex (KFCC, MFDS Notice No. 2025-89).

Item	Ascorbyl glucoside	Ascorbyl tetraisopalmitate	Ethyl ascorbyl ether
Other name in the codex	Ascorbic acid 2-glucoside	테트라이소팔미틴산아스코빌 (Korean synonym)	3-O-ethyl ascorbate
Formula / weight	C12H18O11, 338.27	C70H128O10, 1129.78	C8H12O6, 204.18
Assay	98.0% or more	95.0% or more	95.0% or more, when dried
Description	White to pale yellow powder or crystalline powder	Colourless to pale yellow liquid, slight odour	White to pale yellow crystals or crystalline powder, slight odour, bitter taste
Physical marks	Melting point 158-163 °C; specific rotation +186.0 to +188.0°	Specific gravity 0.930-0.943; refractive index 1.459-1.465	Melting point 111-116 °C; pH 3.0-4.5 (3 g in 100 mL)
Heavy metals / arsenic	20 ppm / 2 ppm or less	20 ppm / 2 ppm or less	20 ppm / 2 ppm or less
Other limits	Free ascorbic acid 0.1% or less; free glucose 0.1% or less; residue on ignition 0.2% or less	Related substances 4% or less in total	Solution colourless to pale yellow and clear
Loss on drying	1.0% or less	0.5% or less	2.0% or less

The table shows that these are physically different materials. Ascorbyl glucoside and ethyl ascorbyl ether are powders or crystals; ascorbyl tetraisopalmitate is a liquid, which is why its monograph uses specific gravity and refractive index instead of a melting point.

Which finished products have monographs?

Each derivative has five single-ingredient dosage-form monographs in Annex 2: lotion, solution, cream, soaked mask and solid. In the MFDS codex, every one of the fifteen begins with the same rule: on assay, the product contains the derivative at 90.0% or more of the labelled amount. The pH line is the product's own standard value plus or minus 1.0, within 3.0 to 9.0; for the soaked mask the liquid pressed from the sheet is tested, and for the solid, products with no water are excluded.

Derivative	Single-ingredient product monographs (Annex 2)	With adenosine (Annex 5)
Ascorbyl glucoside	Lotion, solution, cream, soaked mask, solid	Solution
Ascorbyl tetraisopalmitate	Lotion, solution, cream, soaked mask, solid	None
Ethyl ascorbyl ether	Lotion, solution, cream, soaked mask, solid	Lotion, solution, cream, soaked mask

Annex 5 covers products for both whitening and wrinkle improvement. Ascorbyl glucoside appears there once, in an ascorbyl glucoside and adenosine solution. Ethyl ascorbyl ether appears four times, paired with adenosine as a lotion, solution, cream and soaked mask. Ascorbyl tetraisopalmitate has no combination monograph. In each combination, the MFDS codex requires the product to contain at least 90.0% of the labelled amount of both ingredients.

What claim does a Korean vitamin C product get?

Through Annex 2, these derivatives belong to the two whitening types of Article 2 of the Enforcement Rule:

• Item 1: 피부에 멜라닌색소가 침착하는 것을 방지하여 기미ㆍ주근깨 등의 생성을 억제함으로써 피부의 미백에 도움을 주는 기능을 가진 화장품 — *helps whiten the skin* by preventing melanin from depositing and so holding back spots and freckles.
• Item 2: 피부에 침착된 멜라닌색소의 색을 엷게 하여 피부의 미백에 도움을 주는 기능을 가진 화장품 — *helps whiten the skin* by lightening melanin that has already deposited.

The wording stops at "helps". Antioxidant, collagen and anti-ageing claims are not in either whitening type, and wrinkle claims belong to item 3, which in the codex is served by retinoids and adenosine, not by these derivatives on their own. Treatment words are drug language and fall outside cosmetic law.

Vitamin C label checklist

From the same MFDS annex:

• Check the ingredient name against the three derivatives in Annex 2
• Do not expect a functional whitening monograph for plain ascorbic acid
• Read "90.0%" as a check against the labelled amount, not a strength
• A vitamin C plus wrinkle claim matches an adenosine combination in Annex 5
• Keep the claim at "helps whiten"; antioxidant or collagen claims are not whitening types

Five steps to check a vitamin C claim

• Read the functional type on the label.
• Find which derivative is the named functional ingredient.
• Open MFDS Notice 2025-89 and locate its monograph in Annex 2.
• For a dual claim, look for the pairing with adenosine in Annex 5.
• Compare the wording with Article 2, items 1 and 2, of the Enforcement Rule.

Use levels for any derivative. The codex sets none; those are in other MFDS rules not read here.

The full codex list, grouped by functional type, is in our K-beauty functional ingredient index.

Sources and how to check

• 기능성화장품 기준 및 시험방법 (Standards and Test Methods for Functional Cosmetics, KFCC), MFDS Notice No. 2025-89, amended 16 December 2025: Annex 1 (general rules), Annex 2 (whitening monographs), Annex 5 (whitening and wrinkle combinations). Korean Law Information Center: https://www.law.go.kr/LSW/admRulInfoP.do?admRulSeq=2100000269816&chrClsCd=010201
• 화장품법 시행규칙 제2조 (Enforcement Rule of the Cosmetics Act, Article 2), items 1 and 2 quoted above: https://www.law.go.kr/법령/화장품법%20시행규칙/제2조
• Checked as of 12 October 2026, against the annex files of the notice. Licence: unprotected works under Copyright Act Article 7.