Potassium is unusual among the minerals covered by Japan’s nutrient-function labelling system, because the format of the product changes whether the claim is even available. A tablet or capsule — the format most brands default to — cannot carry Japan’s potassium function claim at all. Brands abroad who assume potassium works like zinc or calcium often only discover this after specifying the wrong format.
This guide covers what the blood-pressure research on potassium shows, Japan’s fixed nutrient-function wording and its unusual format exclusion, and the genuine kidney-function caution that comes with it.
Health supplements are foods, not medicines, and are not a substitute for medical treatment. Nothing here is a claim that any product prevents, treats or cures a disease.
💬 Planning a potassium product made in Japan? We check the full formula against Japanese food law first. See Japan-made supplement OEM.
What the research shows
Increased potassium intake lowers blood pressure in adults with hypertension, based on a large pooled analysis of randomised trials, with the clearest effect at higher intakes and in people who already have raised blood pressure.
| Study | Design/What was analysed | Reported result |
|---|---|---|
| Systematic review and meta-analyses, BMJ 2013 (PMID 23558164) | 22 randomised controlled trials (1,606 participants) and 11 cohort studies (127,038 participants) on potassium intake and cardiovascular risk factors and disease | Higher potassium intake lowered systolic blood pressure by 3.49 mmHg and diastolic pressure by 1.96 mmHg in adults with hypertension; the largest reduction (systolic −7.16 mmHg) was seen at potassium intakes of 90–120 mmol/day; the effect was specific to people with hypertension, not those with normal blood pressure |
This is a single large pooled analysis rather than several independent studies, so the table above reflects the strength of the underlying trial base rather than multiple confirming sources. The effect is specific to people who already have high blood pressure, at higher potassium intakes than a typical supplement serving provides, and the review does not describe potassium supplementation as a treatment for hypertension in place of medical care.
Checked against the published abstracts on 25 September 2026.
What Japanese products say
Japan’s Foods with Nutrient Function Claims (栄養機能食品) system lets a potassium product carry one fixed sentence once the daily intake amount falls between 840 mg and 2,800 mg — but only if the product is not a tablet, capsule or similar formed processed food.
Under the Consumer Affairs Agency’s Food Labeling Standards, potassium is explicitly excluded from this labelling route for products in tablet, capsule or similar solid dosage forms, even though it otherwise sits on the same list as zinc, calcium, iron, copper and magnesium. The permitted function statement (our translation) is:
- “Potassium is a nutrient necessary for maintaining normal blood pressure.”
The mandatory caution wording (our translation) includes the standard “does not cure disease” sentence, plus a caution specific to potassium: “People with reduced kidney function should avoid this product.”
Two points for a brand abroad:
- Format decides eligibility before dose does. A tablet or capsule potassium product cannot use this labelling route in Japan regardless of the amount per serving; a powder, drink mix or similar format is required if the nutrient-function claim matters to the brand.
- The kidney-function caution is not boilerplate. Impaired kidneys cannot excrete potassium normally, and it is a real, independently understood risk — this caution has to appear in full alongside the function claim.
💬 Need help choosing a dosage form that keeps Japan’s nutrient-function claim available? We prepare the comparison with the manufacturing documents. Tell us your market.
Wording that stays on safe ground
Describe potassium by its studied role in blood pressure among people who already have hypertension, and keep the kidney caution visible rather than treating it as fine print.
| Safer wording | Wording to avoid |
|---|---|
| ”Studied for blood pressure in adults with high blood pressure, at higher intakes than typical supplement doses" | "Lowers blood pressure” as a blanket claim, or any implication it replaces blood pressure medication |
| ”Contains potassium” with the amount per serving, inside Japan’s notified range if using the Japanese wording and format | Formulating a tablet or capsule and assuming Japan’s nutrient-function wording still applies |
| Naming the kidney-function caution plainly | Omitting or softening the caution for people with reduced kidney function |
How potassium is formulated
Because Japan excludes tablets and capsules from the nutrient-function route, the dosage-form decision for potassium is a regulatory decision as much as a manufacturing one.
| Dosage form | Why brands choose it | What to weigh up |
|---|---|---|
| Powder or drink mix | The formats that remain eligible for Japan’s nutrient-function claim | Taste of potassium salts can be bitter or salty; flavouring matters |
| Tablet or capsule | Familiar, simple format | Cannot carry Japan’s potassium nutrient-function claim, whatever the dose |
Decisions that shape the specification:
- Format first. If the Japanese nutrient-function claim is part of the plan, the format must be powder, drink or a similar non-tablet, non-capsule processed food from the outset.
- Amount per serving. For a Japanese Foods with Nutrient Function Claims product, the daily amount must sit between 840 mg and 2,800 mg.
- Potassium source. Potassium chloride, potassium citrate and potassium from food-derived sources differ in taste and solubility; specify the source with the supplier.
- Kidney-function caution. Any potassium product, regardless of format or market, should carry a clear caution for people with reduced kidney function, consistent with the reasoning behind Japan’s mandatory wording.
The check that comes first
Every ingredient must be permitted in foods in Japan, or a Japanese factory cannot make the product.
Potassium is a well-established food mineral in Japan; the formulation risk here is entirely about format and dose rather than legal permission. See the Japan-made supplement OEM page, and compare with our magnesium and calcium guides for how the same Foods with Nutrient Function Claims system applies to other minerals without a format restriction.
Before you ask for a quotation
A factory can quote accurately once the potassium source, the amount, and — critically — the dosage form are fixed.
- Potassium source and amount per serving
- Dosage form — confirm powder, drink mix or similar if Japan’s nutrient-function wording is intended, since tablets and capsules are excluded
- Whether you intend to use Japan’s Foods with Nutrient Function Claims wording, and if so, confirmation the amount falls inside 840–2,800 mg
- Companion ingredients and their amounts
- Countries you will sell in, and potassium’s status and upper-limit guidance there
💬 Ready to design a Japan-made potassium product? Send us the concept — amount, form, companion ingredients and the countries you will sell in.
Frequently asked questions
1. Can a potassium tablet carry Japan’s nutrient-function claim?
No. Japan’s Foods with Nutrient Function Claims system explicitly excludes potassium when the product is a tablet, capsule or similar formed processed food, even though potassium is otherwise on the same nutrient list as zinc, calcium and magnesium. A powder or drink format is needed for the claim.
2. Does potassium really lower blood pressure?
A large 2013 meta-analysis found that higher potassium intake lowered blood pressure specifically in adults with hypertension, with the biggest effect at intakes well above a typical single supplement serving. It was not shown to lower blood pressure in people with normal readings.
3. What can a Japan-made potassium product say on its Japanese label?
If the daily amount is between 840 mg and 2,800 mg and the format is not a tablet or capsule, it can carry fixed wording about maintaining normal blood pressure, plus a mandatory caution for people with reduced kidney function.
4. Why does Japan single out kidney function for potassium?
Impaired kidneys cannot excrete potassium normally, so excess intake can build up to dangerous levels in that population — a well-established clinical concern, which is why the caution is mandatory rather than optional.
5. Is potassium a substitute for blood pressure medication?
No. The research describes a modest blood-pressure effect from higher potassium intake in a specific population; it is not evidence that a supplement can replace medical treatment for hypertension.
Sources: “Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses”, BMJ 2013;346 (PMID 23558164); Consumer Affairs Agency Food Labeling Standards, Appended Table 11 (食品表示基準 別表第11), for potassium’s Foods with Nutrient Function Claims wording, caution statement, lower/upper limits, and the tablet/capsule format exclusion. Checked on 25 September 2026.