Magnesium Oxide (산화마그네슘): Korean Regulatory Record

Magnesium oxide (Korean: 산화마그네슘) is one of the eleven raw-material forms named in Korea’s Health Functional Food Code for the nutrient magnesium. It appears in the Code as item 나 of the permitted list in Section 3, article 1-16. It is recorded here as an entity in its own right for one reason: the same compound is simultaneously the active ingredient of approved over-the-counter drugs, and it carries a food-additive identity as well. One substance, three registers, three different sets of permitted wording.

That overlap is not a curiosity. It is where most consumer-facing writing about magnesium goes wrong, and the error is usually arithmetic before it is regulatory. Health functional food figures for magnesium are stated as the element. Drug dosages for magnesium oxide are stated as the compound — the label says “as magnesium oxide” and then gives a figure in grams. Comparing the two directly puts a gram figure against a milligram figure and produces a difference that looks like an order of magnitude but is not one.

The drug label supplies the conversion needed to compare them properly: 250 mg of magnesium oxide corresponds to 150 mg of magnesium. On that basis the lowest approved antacid dose, 0.5 g of magnesium oxide per day, works out to roughly 300 mg of elemental magnesium — just above the top of the health functional food daily intake range rather than far from it. The two frameworks are closer in quantity than the raw numbers suggest. What separates them is the regulatory category and the approved indication, not the size of the dose.

This page records what the Code and the drug approvals actually say about magnesium oxide, and where the wording of one may not be carried into the other. The functional statements available to a magnesium product belong to the nutrient article and are documented on the Magnesium record; nothing on this page adds a function that the Code does not provide.

Ingredient Snapshot

Chemical identity is taken from PubChem. The raw-material listing, specification, and daily intake are taken from the MFDS Health Functional Food Code. Drug status, indications, and dosage are taken from the MFDS drug product database.

Regulatory Records

Why a Raw-Material Form Gets Its Own Record

Most of the eleven permitted forms in article 1-16 are documented on the Magnesium record and do not need separate entries. Magnesium oxide is recorded separately because it is named in more than one register at the same time, and each register attaches different wording to it.

In the Health Functional Food Code it is a permitted raw material — a way of supplying the nutrient, with no functional statement of its own. In the drug register it is an active ingredient with approved indications and its own dosage. As a food additive it carries the INS number 530. The compound does not change across those three; what changes is which statements may lawfully accompany it, and under which framework a given product was approved or notified.

This is the same pattern recorded for other substances in this database that sit across a regulatory boundary. The practical consequence is narrow and specific: a claim that is correct in one register is not thereby available in another.

The Two Ends of the Daily Intake Range Are Not the Same Kind of Rule

Article 1-16 states a daily intake of 94.5–250 mg, which reads like a band with a floor and a ceiling. The Code’s general provisions for nutrients treat the two ends differently.

The lower figure is derived and mandatory: the minimum content of vitamins and minerals shall be at least 30% of the daily nutrient reference value, and 30% of magnesium’s 315 mg reference value is exactly 94.5 mg. The upper figure is applied as a voluntary standard (임의기준) against the labeled amount of the finished product, rather than as a binding ceiling. This page therefore does not cite 94.5–250 mg as though both ends bound a product equally. The provision applies to vitamins and minerals; it does not extend to the functional ingredient articles elsewhere in the Code.

One further point specific to this page: the intake figures are set as elemental magnesium, not as the salt. Content standards are not adjusted for salt form or for absorption. A product using magnesium oxide and a product using magnesium gluconate are measured against the same elemental figure.

Notification-Number Note

The article text on this page was checked against the consolidated notification text itself. The full text of notification 제2026-43호 was obtained from the MFDS notification board as the published attachment archive and read directly, and Section 3, item 1-16 was compared clause by clause with what is recorded here — the permitted raw-material list 가 through 카, the content specification of 80–150%, the two functional statements, the daily intake of 94.5–250 mg, and the test method reference to Section 4, item 3-15 all match.

For context: the two amendments since 제2025-11호 — 제2026-32호 dated 2026-04-13 and 제2026-43호 dated 2026-06-11 — do not list article 1-16 among the amended provisions, and the magnesium test method at Section 4, item 3-15 is not among the test methods revised in 제2026-32호. What this establishes is that the article text recorded here matches the current consolidated notification as of the verification date. It is not a redline history of how each clause reached its present wording.

Claim Safety Matrix

The classifications below are the claim-handling categories recorded in this database — Allowed, Caution, Avoid, and Prohibited. They describe how wording is treated in this record and require human review; they are not legal determinations issued by MFDS, and they do not by themselves settle the lawfulness of a particular label, advertisement, news report, or academic discussion.

The two notified functional statements are recorded as Caution rather than Allowed. They belong to the nutrient article rather than to this salt form, and their use depends on the product being a qualifying health functional food supplying the specified daily intake of magnesium. That classification does not indicate that the notified wording lacks a basis in the Code.

Both Prohibited entries below rest on a positive regulatory instrument located in this record — an approved drug indication that occupies the wording — rather than on the absence of a registration.

Evidence Boundaries: What This Page Does Not Claim

The following claims are outside the scope of this ingredient record:

Treatment or prevention of any disease. Magnesium oxide is the active ingredient of approved over-the-counter drugs, and those approvals carry indications. Those indications belong to the approved drug products and to the framework that granted them. This page records them as a boundary, not as claims available to a health functional food, and it does not state or imply that a supplement treats gastritis, hyperacidity, ulcer, or constipation.

Pharmaceutical efficacy or pharmaceutical dosing by implication. Drug dosages on this page are stated as the compound and are reproduced only to mark where the frameworks diverge. They are not intake guidance, and they must not be read alongside the health functional food figures as though the two were the same measurement.

Individual outcomes. Nothing here predicts what any particular person will experience. Daily intake figures in the Code are labeling and product-composition standards, not personal recommendations, and they are not adjusted for individual circumstances.

Product-level guarantees or comparisons between salt forms. This page does not evaluate specific products and does not rank magnesium oxide against other permitted forms for absorption, tolerability, or effect. The Code sets content standards on elemental magnesium and does not differentiate the permitted forms on those grounds; this record does not supply a comparison the source material does not make.

Cosmetic status. Cosmetic naming and role for magnesium oxide were not researched within the scope of this record and are marked Unknown rather than inferred.

Currency beyond the verification date

The Health Functional Food Code is amended periodically — twice between March 2025 and June 2026 for this Code alone. The notification number and article information on this page reflect verification as of 2026-08-02. Later amendments, drug-label changes, and register additions or cancellations may change the applicable record.

Related Entities

Related Ingredients

• Magnesium — the nutrient article this raw material supplies; functional statements, daily intake, and the full permitted list are recorded there
• Magnesium Hydroxide — another notified raw-material form under article 1-16, and likewise an OTC drug active ingredient (마그밀정, item 197400246)
• Magnesium Citrate and Magnesium Glycinate — widely marketed forms not named among the eleven listed items
• EPA and DHA-Containing Oil — notified functional ingredient article in the same Code

Related Product Types

• Health functional food — magnesium tablets and capsules formulated with magnesium oxide
• Health functional food — multi-nutrient products supplying magnesium
• Over-the-counter drug — magnesium oxide antacid and laxative products
• Food additive applications under INS 530

Related Claims

• Required for energy utilization — notified functional statement of the nutrient article
• Required for maintaining nerve and muscle function — notified functional statement of the nutrient article
• Antacid action — OTC drug indication, not transferable to health functional food claims
• Constipation treatment — OTC drug indication at gram-scale dosing, not transferable

Related Regulatory Concepts

• Permitted raw-material lists as claim boundaries
• Elemental basis versus compound basis in dose figures
• Daily intake (일일섭취량) and labeled-amount tolerance (80–150%)
• Mandatory minimum content versus voluntary maximum standard (임의기준)
• Health functional food and over-the-counter drug boundaries
• Substances registered simultaneously as food raw material, drug active ingredient, and food additive

Source Transparency Note

This page uses the following source classification:

Naming-layer and identity-layer sources are not used as functional-claim evidence. Chemical identity from PubChem establishes what magnesium oxide is; it does not establish what may be stated about its health effects or how it may be labeled in Korea. KCIA (Korea Cosmetic Industry Institute) is not cited on this page, because cosmetic ingredient naming does not determine the status or functional wording of a health functional food raw material. All functional wording recorded here traces to the Health Functional Food Code text, and all indication wording to the drug approval records.

Frequently Asked Questions

Is magnesium oxide a registered ingredient in Korea?
Yes. Magnesium oxide (산화마그네슘) is named as item 나 among the eleven permitted raw-material forms for the nutrient magnesium in Korea’s Health Functional Food Code, Section 3, article 1-16. The consolidated Code verified for this page reflects MFDS notification 제2026-43호 dated 2026-06-11. Separately, magnesium oxide is also the active ingredient of approved over-the-counter drugs, and it carries the food additive number INS 530.

What claims are allowed for magnesium oxide in Korean health functional foods?
None specific to magnesium oxide. Functional statements in the Code belong to the nutrient article, not to individual salt forms, and article 1-16 provides exactly two: required for energy utilization, and required for maintaining nerve and muscle function. Both are recorded here as Caution rather than Allowed, reflecting that they attach to a qualifying health functional food supplying the specified daily intake of magnesium. Magnesium oxide contributes the magnesium; it does not bring functional wording of its own.

Why is magnesium oxide both a supplement raw material and a medicine in Korea?
Because the same compound is registered in more than one framework. In the Health Functional Food Code, magnesium oxide is a permitted way of supplying the nutrient. In the drug register, it is an active ingredient with approved indications — antacid action and constipation — under products such as 마그오캡슐250mg. The compound is identical across both; what differs is which statements may lawfully accompany a product, and under which framework that product was approved or notified. A drug indication does not become available to a supplement because the two share an ingredient.

How much magnesium is in magnesium oxide?
The drug label for 마그오캡슐250mg supplies the figure directly: 250 mg of magnesium oxide corresponds to 150 mg of magnesium. This conversion matters because the two frameworks state their numbers on different bases. Health functional food figures for magnesium are expressed as the element, while the drug dosages are expressed as the compound — “as magnesium oxide”. Comparing a gram figure for the compound against a milligram figure for the element is a unit error, and it is the most common mistake in consumer-facing writing about magnesium oxide.

Can a magnesium oxide supplement be described as relieving constipation?
Constipation is an approved indication of magnesium oxide as an over-the-counter drug, at a labeled dose of 2 g per day expressed as the compound. It is recorded here as Prohibited wording for a health functional food: it states a drug indication, and it implies a quantity the health functional food framework does not provide for, where the daily intake is 94.5–250 mg of elemental magnesium. The presence of the same compound in both products does not carry the indication across.

Is magnesium oxide better absorbed than other magnesium forms?
This page does not answer that, and it is worth being explicit about why. The Code sets content standards on elemental magnesium and does not differentiate the eleven permitted raw-material forms by absorption, tolerability, or effect. No comparison between magnesium oxide and other forms is recorded in the regulatory sources used here, so none is supplied. Comparative absorption claims circulating in marketing are outside the scope of this record in both directions — this page neither endorses nor refutes them.