Advertising Claims for Private-Label Cosmetics in Korea: What You Must Be Able to Prove

The short answer: a claim is settled by whether you can prove it, not by whether it is allowed

One of the most common questions in a brand consultation is whether a particular phrase may be used. Korea's Cosmetics Act is structured a little differently. Instead of handing you one list of permitted wording and another of forbidden wording, it asks for two things at once. First, do not carry out the labelling or advertising that is off limits from the start. Second, for statements that relate to facts, stay in a position where you can substantiate them.

Article 14(1) of the Cosmetics Act provides that a business operator and a seller must be able to substantiate the fact-related matters in their own labelling or advertising. This is not an instruction to assemble evidence after a request arrives; it is a position to be maintained while the labelling or advertising continues. So the moment a phrase is really settled is not when the copy is written, but when the type of study or survey that will support it is decided.

A concept diagram used to explain how a labelling or advertising claim connects to a type of supporting evidence. It is not a photograph of an EVAS product, facility or test record.

1. Two provisions do two different jobs

Article 13(1) of the Cosmetics Act (Act No. 20901, in force 2 April 2026) sets out the labelling or advertising that a business operator or seller must not carry out. The provision in force lists labelling or advertising likely to be mistaken for a drug (subparagraph 1); labelling or advertising likely to cause a cosmetic that is not a functional cosmetic to be mistaken for one, or whose content differs from the review result on the safety and efficacy of a functional cosmetic (subparagraph 2); and other labelling or advertising likely to deceive consumers contrary to fact or cause them to be mistaken (subparagraph 4). Subparagraph 3 was deleted by the amendment of 31 January 2025.

Paragraph 2 of the same Article delegates the scope of labelling and advertising, and other necessary matters, to Ordinance of the Prime Minister, and Article 22 of the Enforcement Rule of the Cosmetics Act (Ordinance of the Prime Minister No. 2109, in force 2 April 2026) provides that this scope and the other matters to be observed are as set out in Attached Table 5.

Article 14 does a different job. It deals with proof rather than with a list of prohibitions. Paragraph 1 requires the operator and the seller to stay in a position where they can substantiate their claims, and paragraph 2 allows the Minister of Food and Drug Safety, where substantiation is deemed necessary in order to determine whether the labelling or advertising falls under Article 13(1)4, to specify the content concretely and request the submission of relevant materials.

2. Some labelling and advertising is off limits from the start

Section 2 of Attached Table 5 to the Enforcement Rule (as amended on 1 August 2025) sets out the matters to be observed in cosmetic labelling and advertising, in items (a) through (k). Most phrases that fall here are not rescued by evidence. Some items are different: item (h) turns on whether the quality or efficacy can be objectively confirmed, and the proviso to item (c) and item (f) allow the wording where their conditions are met, so the list has to be read item by item. This is the first list to check during development.

• Labelling or advertising about content, product names, efficacy, effects and the like that is likely to be mistaken for a drug (item a)
• Labelling or advertising likely to cause a product that is not a functional cosmetic to be mistaken for one, in terms of its name, manufacturing method, efficacy, effects and the like (item b)
• Labelling or advertising stating or implying that a doctor, dentist, oriental medical doctor, pharmacist, medical institution or other expert in the medical or pharmaceutical field designates, certifies, recommends, instructs, researches, develops or uses the cosmetic (item c)
• Labelling or advertising likely to cause a foreign product to be mistaken for a domestic one, or a domestic product for a foreign one (item d)
• Labelling or advertising expressing technical cooperation with a foreign party where no such cooperation exists (item e)
• Comparative labelling or advertising must state the object and criteria of comparison clearly and advertise only objectively confirmable matters, and must not use exclusive absolute expressions such as best or finest (item f)
• Labelling or advertising that is contrary to fact, or that is only partly true yet likely as a whole to mislead consumers, or that deceives consumers or is likely to do so (item g)
• Labelling or advertising of quality, efficacy and the like that cannot be or has not been objectively confirmed, or that goes beyond the scope of a cosmetic under subparagraph 1 of Article 2 of the Act (item h)
• Labelling or advertising using vulgar or repulsive expressions, designs, photographs and the like (item i)
• Labelling or advertising expressing or implying that the cosmetic contains a processed product of an internationally endangered species (item j)
• Labelling or advertising that disparages another product, or is suspected of doing so, regardless of whether the statement is true (item k)

Item (c) carries a proviso. Where a human application study result that meets the definitions in subparagraphs 1 through 3 of Article 2 of the Act has been publicly recognised through presentation at a relevant academic society or similar, the related literature may be cited within that scope; in that case the original meaning of the cited literature must be conveyed accurately, and the researcher's name, the title of the literature and the date of publication must be stated clearly. Borrowing an expert's name for an advertisement and citing recognised literature on those terms are two different things.

Item (f) is also easy to miss. Comparative advertising is not banned as such; it is permitted only on the conditions set out in that item.

3. How far does the substantiation duty reach

Article 23(1) of the Enforcement Rule defines the subject of substantiation under Article 14(1) of the Act as labelling or advertising carried out on cosmetic packaging, or through the advertising media or means listed in section 1 of Attached Table 5, which is likely to deceive consumers contrary to fact or cause them to be mistaken and which the Minister of Food and Drug Safety deems to require substantiation.

The media or means in question are listed in section 1 of Attached Table 5: newspapers, broadcasting or magazines; leaflets, pamphlets, samples or admission tickets; the internet or computer communications; posters, signboards, neon signs, advertising balloons or electronic display boards; video products, records, books, publications, films or plays; door-to-door advertising or advertising by demonstration; the packaging of goods other than one's own; and other media or means similar to these. Because the internet and computer communications are included, it is safer to prepare a sentence written on your own online store's product page on the same footing as wording printed on the package.

4. What counts as substantiation material

Article 23(2) of the Enforcement Rule sets out the scope and requirements of the substantiation material to be submitted in three subparagraphs.

• Test results: the data must be human application study data, in-vitro study data or survey data of an equivalent or higher standard (subparagraph 1)
• Survey results: the sampling, the questions and the questioning method must be consistent with the purpose of the survey or with the statistical method used (subparagraph 2)
• Method of substantiation: the test or survey method used must be widely known academically or generally accepted in the relevant industry or the like, and must be scientific and objective (subparagraph 3)

Under the delegation in paragraph 4 of the same Article, the Ministry of Food and Drug Safety notice Regulation on Substantiation of Cosmetic Labelling and Advertising (Notice No. 2020-80, in force 4 September 2020) sets out the detail. Article 3(1) of the notice divides the material that may be recognised as a reasonable basis into test results and survey results, lists human application study data, in-vitro study data and survey data of an equivalent or higher standard as test results, and gives papers and academic literature containing test results related to the labelling or advertising as an example of survey data of an equivalent or higher standard. The proviso to the same paragraph states that, for the labelling and advertising set out in the Attached Table to the notice, the material specified in that Attached Table is recognised as the reasonable basis.

5. Eight expressions whose evidence type is fixed in advance

The Attached Table to the notice, captioned as relating to the proviso to Article 3(1), directly specifies which substantiation material must be submitted for certain labelling and advertising expressions. If you decide early in development to use one of these expressions, the type of evidence to prepare is in effect already chosen for you.

• Suitable for acne-prone skin: submit human application study data
• Antibacterial (limited to products for cleansing the human body): submit human application study data
• Alleviation of skin ageing: submit human application study data or in-vitro study data
• Temporary reduction of cellulite: submit human application study data
• Alleviation of puffiness and dark circles: submit human application study data
• Improvement of skin blood circulation: submit human application study data
• Increase, decrease or activation of collagen: submit data substantiating the function in a functional cosmetic
• Increase, decrease or activation of enzymes: submit data substantiating the function in a functional cosmetic

It is worth noting that five of the eight specify human application study data only. The one item that may instead rest on in-vitro study data is alleviation of skin ageing, while the collagen and enzyme expressions call for data substantiating the function in a functional cosmetic. The antibacterial entry carries a parenthetical limit to products for cleansing the human body.

Claiming efficacy or effects that belong to a functional cosmetic runs through its own procedure. Our article on shampoo development and hair-loss relief claims sets out the review and reporting routes.

6. The material itself has to meet quality requirements

Article 4 of the notice sets out the requirements for test results. The common requirements in subparagraph 1 are as follows.

• The data must relate to the advertised content, rest on scientific and objective methods, and secure reliability and reproducibility (item a)
• The test must have been conducted at a domestic or foreign university or a specialised cosmetics research institution, and the data must be issued by the head of that institution (item b). The parenthetical text states that this includes a company-affiliated research institute that performs work independently of other departments such as manufacturing and sales.
• The test must have followed standardised test procedures, including documented maintenance procedures for instruments and equipment (item c)
• The data must reflect documented reliability-assurance work evidencing that the test was carried out under the procedures established by the testing institution (item d)
• For foreign data, a Korean summary of the main points together with the original text must be available for submission (item e)

Human application studies carry further conditions. Item (a)1) of subparagraph 2 of Article 4 of the notice requires that the study be conducted and evaluated under the guidance and supervision of a relevant specialist physician, or of a person with at least five years of testing experience in cosmetic human application studies at a hospital, a domestic or foreign university, or a specialised cosmetics research institution. The same item also requires ethical principles based on the Declaration of Helsinki, voluntary consent to participate obtained through a documented consent form, and, among other things, selection and withdrawal criteria for subjects set in advance.

Survey results carry their own requirements. Subparagraph 1 of Article 5 of the notice provides that the surveying institution must be independent of the business operator and must have the capacity to carry out the survey, and item (d) of subparagraph 2 provides that the survey must be conducted fairly and that respondents must not be aware of its purpose. This is why a survey run by the brand itself is hard to use as substantiation material as it stands.

7. The evidence has to connect directly to the wording

Article 3(3) of the notice provides that the content of the substantiation material must bear a direct relationship to what the advertisement claims, and gives two examples. This is where practice most often goes wrong.

The first is material that has no relationship to the claim. The notice first gives the example of labelling or advertising about efficacy or performance where what is submitted is a survey of general consumers, or survey results from a limited group of consumers who have used the product, and then the example of labelling or advertising claiming an acne-improving effect for a product where, instead of data proving that the product has that effect, patent material for a cosmetic composition for improving acne-prone skin or the like is submitted. That a patent exists and that this product produces the effect are two different propositions.

The second is material that is only partly related. The notice gives the example of a free-from advertisement stating that a product does not contain a particular ingredient where, instead of test data showing that the ingredient is not present in the product, what is submitted is a manufacturing control record showing that the ingredient was not added during manufacturing, or test data on the raw material. A record that something was not added and a result showing it is not present are not the same statement.

8. Once the request arrives, you have 15 days

Article 14(3) of the Act provides that a business operator or seller requested to submit substantiation material must submit it to the Minister of Food and Drug Safety within 15 days from the date of the request. Under the proviso to the same paragraph, however, the Minister may extend that period where justifiable grounds are recognised.

Article 23(3) of the Enforcement Rule requires the following items to be stated and the materials evidencing them to be attached on submission: the method of substantiation; the name of the testing or surveying institution and the name, address and telephone number of its representative; the content and result of the substantiation; and, where part of the material is a trade secret that you do not wish to disclose, that content together with the reason. In other words, protecting a trade secret requires stating the content and the reason at the point of submission.

The Act also covers what happens when the deadline is missed. Article 14(4) provides that where a business operator or seller, having been requested to submit material, continues the labelling or advertising without submitting it within the period, the Minister shall order the labelling or advertising to be suspended until the material is submitted. The provision is written as a duty, not a discretion.

Article 37(1) then imposes imprisonment for not more than one year or a fine not exceeding 10 million won on a person who violates Article 3-6, Article 4-2(1), Article 9, Article 13, Article 16(1)2 or 3, Article 16(2) or Article 28-4(3), or who fails to comply with a suspension order under Article 14(4). Within the scope of this article, the relevant triggers are a violation of Article 13 and non-compliance with a suspension order under Article 14(4). Under paragraph 2 of the same Article, imprisonment and a fine may be imposed together.

Separately, Article 14(5) allows a party that has submitted material through this procedure to refuse a submission demanded by another authority under other statutes such as the Act on Fair Labeling and Advertising, and paragraph 6 requires the Minister to comply, absent special grounds, with a request for that material from another authority.

9. What to settle during development

Choosing the wording first and hunting for evidence later works against you on budget and on schedule alike. It is better to write the following into the development brief.

• Have the sentences intended for the package and the product page been listed exactly as they will read?
• Does any of those sentences fall under the matters to be observed in section 2 of Attached Table 5?
• Among the remaining sentences, which are fact-related claims, and what will prove each one?
• Does any sentence match one of the eight expressions in the Attached Table to the notice, and if so can the specified type of data be obtained?
• Has any wording that belongs to functional-cosmetic efficacy and effects crept in?
• Which institution will run the test or survey, and does it meet item (b) of subparagraph 1 of Article 4, or subparagraph 1 of Article 5, of the notice?
• Who is responsible for the final report, its issuing body and its storage location?

If writing the brief is itself new territory, how to write a good product brief is a reasonable starting point. Mandatory package items and date marking are covered separately in our article on shelf life and period after opening, and the duties a brand keeps even when manufacturing is outsourced are set out in our article on brand-owner responsibilities.

10. What changes for export-only products

Article 30 of the Act provides that products not sold domestically and intended solely for export may follow the regulations of the importing country, with Article 4, Articles 8 through 12, Article 14, subparagraphs 1 and 5 of Article 15, Article 16(1)2 and 3, and Article 16(2) not applying to them.

Two points have to be kept apart here. Article 14 is on that list, so the substantiation provisions do not apply to products intended solely for export. Article 13 is not on the list. The phrase Articles 8 through 12 stops at Article 12, so it does not reach Article 13. The prohibition on improper labelling and advertising therefore still applies to products intended solely for export.

The exception also rests on a premise: products not sold domestically and intended solely for export. If a product is sold both at home and abroad, that premise does not hold. And the possibility of following the importing country's regulations means those labelling and advertising rules must be checked separately; this article is limited in scope to the laws of the Republic of Korea.

11. What changes from 27 November 2026

Article 13(1) as currently in force consists of subparagraphs 1, 2 and 4. On the same page of the Korea Law Information Center, however, an amended provision scheduled to take effect on 27 November 2026 is displayed alongside it. The amendment inserts a new subparagraph 4 prohibiting advertising that uses virtual sound, images or video and the like that are generated by an artificial intelligence system as defined in subparagraph 2 of Article 2 of the Framework Act on the Development of Artificial Intelligence and the Establishment of a Foundation for Trust and that are hard to distinguish from reality, where the advertising is likely to create the false impression that a doctor, dentist, oriental medical doctor, veterinarian, pharmacist, oriental pharmacist, university professor or other expert in a relevant field endorses, designates, certifies, recommends, instructs or uses the cosmetic. The existing catch-all moves to subparagraph 5, and the cross-reference in Article 14(2) shifts to Article 13(1)5 accordingly.

As of 19 September 2026, when this article was written, the amendment is not yet in force. Even so, if you are planning creative in which an expert figure appears through generated images or video, it is safer to review that content plan on the assumption of the effective date.

Frequently asked questions

Do customer reviews and influencer content fall within the substantiation duty?

Article 23(1) of the Enforcement Rule defines the subject as labelling or advertising on cosmetic packaging or through the media and means in section 1 of Attached Table 5 that the Minister of Food and Drug Safety deems to require substantiation, and Article 14(1) of the Act addresses business operators and sellers. Whether particular content falls within that scope turns on who actually carries out the labelling or advertising and in what form, so individual cases need confirmation from a professional adviser or the competent authority. This article explains the structure of the provisions; it does not replace that case-by-case judgement.

Is test data from an in-house research institute accepted?

Item (b) of subparagraph 1 of Article 4 of the notice requires data from a test conducted at a domestic or foreign university or a specialised cosmetics research institution, issued by the head of that institution, while the parenthetical text states that this includes a company-affiliated research institute that performs work independently of other departments such as manufacturing and sales. The question is whether the independence and issuing-body requirements are met. For survey results, subparagraph 1 of Article 5 imposes its own independence requirement on the surveying institution.

Does citing a paper amount to substantiation?

Article 3(1)1 of the notice gives papers and academic literature containing test results related to the labelling or advertising as an example of survey data of an equivalent or higher standard. Because paragraph 3 of the same Article requires a direct relationship to what the advertisement claims, however, a paper about a different product or about an ingredient in general does not by itself prove your product's claim. When citing literature involving experts, the conditions in the proviso to item (c) of section 2 of Attached Table 5 also have to be checked.

What about wording such as best or finest?

Item (f) of section 2 of Attached Table 5 requires comparative labelling and advertising to state the object and criteria of comparison clearly and to advertise only objectively confirmable matters, and prohibits labelling or advertising using exclusive absolute expressions such as best or finest. Even where figures are offered as support, the first point to check is that the absolute expression itself is restricted.

How long does substantiation material need to be ready?

Article 14(1) of the Act requires the operator and the seller to stay in a position where they can substantiate their claims, and paragraph 3 of the same Article sets submission within 15 days from the date of the request. Read together, they presuppose keeping the material in a state fit for submission for as long as the labelling or advertising continues. Retention periods for particular records tied to ingredient or product characteristics are set by other provisions, so those are worth checking product by product as well.

Talk to us before the wording is fixed

EVAS runs planning, design, research, manufacturing, logistics and brand content in house. Putting the sentences you want to use on the table while the product concept is still being shaped makes it possible to work out, at the stage where the formula and product type are decided, which claims need which kind of evidence.

That said, this article organises the structure of the statutes and notices of the Republic of Korea; it is not legal advice on the lawfulness of any particular wording. Judgements on individual expressions and the substantiation plan that follows depend on the product and on the labelling and advertising content. If you have a product in mind, look through the formula library and the development process, then get in touch through the contact page. Our other pieces are collected in the insights index.