A serum brief usually arrives as a list of ingredients the brand wants to name on the front of the box: a vitamin derivative, a peptide, several plant extracts, perhaps “brightening” in the headline. The trouble starts when that list meets a Japanese factory. Some of the claims on the mock-up belong to a different legal category, the extracts multiply the ingredient list, and the preservative system that worked in another market may not be on Japan’s list at all. This guide sets out what to decide before the factory quotes, so the first sample is close to the product you can actually sell.
💬 Sunsho Trade manages Japan-made own-brand cosmetics for brands outside Japan, in English, from brief to shipment. Send us your serum concept and target claims and we will tell you what the factory will ask for first.
Decide the category before you choose the actives
Decide first whether your serum is a cosmetic or a quasi-drug (医薬部外品), because a “whitening” or “wrinkle improvement” claim is only available to an approved quasi-drug and that changes the whole project.
Serums sit closer to the boundary than any other skincare product. Under Japan’s Act on Securing Quality, Efficacy and Safety of Products Including Pharmaceuticals and Medical Devices (the PMD Act), a cosmetic has a mild action on the body. Quasi-drugs are a separate category under Article 2(2), and the typical serum-type quasi-drugs are “medicated cosmetics” that claim whitening — in Japan’s quasi-drug wording, suppressing melanin production to prevent spots and freckles — or wrinkle improvement. Both are regulatory categories. They are not promises any label can make freely, and in Japan a wrinkle-improvement claim exists only for approved quasi-drugs.
The practical difference is large. A cosmetic is notified before it goes on the Japanese market. A quasi-drug needs product-by-product marketing approval (製造販売承認), built around an approved active ingredient. If your brief depends on either claim, say so on day one, because the factory will plan a different formula, a different document set and a different schedule. The full decision, and what pushes a product over the line, is set out in cosmetic or quasi-drug: the first decision in a Japanese OEM project.
How a Japanese factory builds a serum
A serum is usually a water-based or water-and-glycol base with a thickener, a set of functional ingredients at the levels you want to name, and a preservative system from Japan’s positive list; the decisions that matter are texture, the active load and the container.
A Japanese factory will normally start from one of its own base formulas and adjust it, rather than design from zero. Whether that suits you, and who owns the result, is covered in stock base or custom formula. For a serum, the brief should settle four things.
Texture. “Serum” covers everything from a watery essence to a gel that holds its shape on the finger. Describe the feel with a reference you can send — a product you already sell, or a sample you like — and say how it should behave after it is spread: absorbed quickly, slightly tacky, cushioned.
The active load. If you plan to name an ingredient on the front of the pack, tell the factory at what level you need it to be present for your own marketing reasons. The factory will tell you whether that level is compatible with the base, the pH and the stability it needs.
Extracts. Brands like long extract lists. Each extract brings its own solvent, often a glycol or water, and sometimes a preservative carried over from the raw material. That affects both the preservative check and the ingredient list, as shown below.
Fragrance and colour. Decide early whether the serum is fragrance-free. If it is coloured, the colourant has to fit Japan’s rules on tar colours.
| Brief item | What to send the factory | Why it matters |
|---|---|---|
| Legal category | Cosmetic or quasi-drug, decided by you | Sets the formula route and documents |
| Texture | A reference product or sample, plus a short description | Avoids sample rounds spent on feel alone |
| Named ingredients | Each ingredient you want on the front, and the level you need | Checked for compatibility and stability |
| Extracts | The list, and whether a shorter list is acceptable | Each adds solvents and possibly carried-over preservatives |
| Fragrance | Fragrance-free or fragranced, with a direction | Changes the ingredient list and the sample |
| Container | Dropper, pump, airless or other | Affects preservation and the stability programme |
| Markets | Every country you will sell in | The factory needs this before the formula check |
Preservatives and the positive list
Every preservative in your serum, including any carried in with an extract, has to be on Appendix 3 of Japan’s Standards for Cosmetics and under the limit for a leave-on product.
Japan’s Standards for Cosmetics (化粧品基準), Ministry of Health and Welfare Notification No. 331 of 2000, work in two directions. Appendix 1 lists substances a cosmetic must never contain. Appendices 3 and 4 are positive lists: a preservative must come from Appendix 3, and a UV filter from Appendix 4, with limits that differ by product type. A serum is a leave-on product, so it is held to the limits for leave-on products, which can differ from those for rinse-off products such as shampoo.
This is where formulas written for another market most often fail. A preservative that is permitted elsewhere may not appear on Japan’s list, or may be listed with a lower limit for a leave-on product. The formula check therefore runs ingredient by ingredient, before samples, and it includes the preservatives that arrive inside raw materials, not only the ones added on purpose. How that check works, and what typically has to change, is the subject of checking a formula against Japan’s Standards for Cosmetics.
One serum-specific point:
- “Preservative-free” claims. If you want a preservative-free or reduced-preservative serum, raise it in the brief. It affects the container choice and the preservative-efficacy testing the factory runs, and it is a design decision, not a label decision.
Checked against the published texts of the Ministry of Health, Labour and Welfare, the Japan Cosmetic Industry Association and prefectural guidance on 17 October 2026.
The container is part of the formula
Choose the container before the final sample, because a dropper, a pump and an airless bottle expose the serum differently and the stability and compatibility tests are run in the container you will sell.
A dropper bottle lets air in at every use and invites contact with fingers. An airless pump keeps the product sealed but limits how thick the serum can be and how much is left at the end. A standard pump sits in between.
The factory designs the stability programme — typically storage at different temperatures, exposure to light, temperature cycling and contact with the container — and there is no single Japanese statutory protocol for it. What you need is the result in the container you will actually ship. If you change the container after the test, ask whether the compatibility part has to be repeated. The detail is in stability and compatibility testing, and container choices in general are covered in containers and packaging.
💬 Not sure whether your extract list or preservative system will pass Japan’s lists? Send the draft INCI list and we will have it checked before any sample is made.
What to test on the samples
Use each sample round to judge feel, appearance, smell and how the serum behaves in the real container — and keep a written record of what you approved, because the approved sample becomes the production standard.
A useful sample review for a serum covers:
- Feel on the skin, in the climate where you will sell. A serum that feels right in an air-conditioned office may feel heavy in humid weather.
- Layering. Apply it under the moisturiser or sunscreen you expect customers to use, and look for pilling.
- Dispensing. Does the dropper or pump deliver a sensible amount? Does it drip or clog?
- Smell, including the base smell of an unfragranced product.
Say clearly which sample you approve, by its sample code, and keep that code in your records. Anything you change after approval — a new extract, a different container — is a new sample.
What the label may say
A cosmetic serum may claim only effects within Japan’s list of 56 items, such as “moisturises the skin” or “gives the skin firmness”; the dry-skin fine-lines claim needs testing, and whitening or wrinkle improvement are quasi-drug categories.
Japan’s efficacy range for cosmetics (化粧品の効能の範囲) lists 56 items, and a product may use only those that apply to it. The items that serum brands most often use include “moisturises the skin”, “keeps the skin healthy”, “prevents dryness of the skin”, “softens the skin”, “gives the skin firmness”, “gives the skin lustre” and “makes the skin smooth”. These are the rule’s words. They describe what a label is allowed to say, not a result anyone can guarantee.
Item 56, “makes fine lines caused by dryness less noticeable”, was added by a Ministry notice in July 2011. To use it, the marketing authorisation holder must confirm the effect on its own responsibility, through testing such as the Japanese Society of Cosmetic Chemists’ guideline for evaluating anti-wrinkle products. Prefectural guidance treats wrinkle prevention or removal, and removal of sagging, as outside the range. Sensory and makeup effects may be described as long as they are true and do not guarantee a result. The whole list, and why it matters even when you sell outside Japan, is in what a cosmetic label may claim in Japan.
| Claim on your draft | Where it sits in Japan |
|---|---|
| ”Moisturises the skin”, “gives the skin lustre” | Within the cosmetic efficacy range |
| ”Makes fine lines caused by dryness less noticeable” | Cosmetic item 56, only after the effect is confirmed by testing |
| ”Brightening” or “whitening” in the melanin sense | Quasi-drug category, needs an approved active and product approval |
| ”Wrinkle improvement” | Quasi-drug category only |
| ”Reduces wrinkles”, “lifts sagging” | Outside the cosmetic range under prefectural guidance |
Full ingredient labelling for an extract-heavy serum
A serum with many extracts produces a long ingredient list, because each extract’s substance and its extraction or dilution solvents are listed separately unless the solvent does not remain in the product.
Since April 2001 every cosmetic in Japan has had to list all its ingredients, using Japanese labelling names from the Japan Cosmetic Industry Association’s list. Ingredients are listed in descending order of amount, but those at 1% or less, and colourants, may be listed in any order among themselves. Premixed raw materials are listed ingredient by ingredient. Fragrance ingredients may be listed together as “fragrance” (香料). Carry-over ingredients present at levels where they have no effect need not be listed.
For a serum this has two consequences. First, an extract list on your marketing brief can turn into a much longer ingredient list, because the solvents count too. Second, the factory’s list is in Japanese labelling names, and most export labels need INCI names. Those are separate systems, and the conversion has to be done and checked rather than assumed. The method is in full ingredient labelling and INCI conversion.
From approved serum to shipment
Once the formula and container are approved, the remaining decisions are labels, expiry dating and documents — and a label made only for export turns the job into “manufacturing” that needs an export notification.
If the serum is designed for export from the start, or a Japanese product is relabelled in another language, the factory needs a cosmetics manufacturing licence and must file an export manufacturing notification (輸出用化粧品製造届) before manufacture starts. That filing is the factory’s or its partner’s task, but it affects your schedule, so ask about it when you approve the artwork.
On dates, Japanese rules require an expiry date only for cosmetics whose quality may change within a defined period after manufacture under appropriate storage. The threshold usually cited is three years from manufacture — confirm this against the current ministerial notice before you rely on it. Many export markets have their own date rules, such as a period-after-opening symbol; check with your importer.
Your importer files the destination notification and will know which documents the authority wants. We prepare the Japan-side set, described in export documents and certificates. If Vietnam is a destination, see Vietnam’s cosmetics import notification. If you want to sell in Japan itself, the licensing route is different; see importing cosmetics into Japan.
💬 Ready to brief a serum? See how our Japan-made cosmetics OEM service works, browse the Japan cosmetics OEM guide, or send us your brief.
Frequently asked questions
1. Can a Japan-made serum be sold as “brightening”?
Not as a cosmetic in the melanin sense. In Japan, whitening — suppressing melanin production to prevent spots and freckles — is a quasi-drug claim that needs an approved active ingredient and product-by-product approval. A cosmetic may use items in the 56-item range, such as “prevents spots and freckles caused by sunburn” where it applies to the product.
2. Can my serum claim to reduce fine lines?
A cosmetic may use item 56, “makes fine lines caused by dryness less noticeable”, only after the marketing authorisation holder confirms the effect by testing such as the Japanese Society of Cosmetic Chemists’ guideline. Wrinkle improvement is a quasi-drug category, and wrinkle removal is outside the cosmetic range.
3. Why did the factory ask me to change my preservative?
Japan uses a positive list for preservatives (Appendix 3 of the Standards for Cosmetics), with limits that differ by product type. A preservative allowed in another market may be missing from the list or carry a different limit for a leave-on product like a serum.
4. Does the container really need to be fixed before the last sample?
Yes, in practice. The factory runs stability and compatibility checks in the container you will sell. A dropper, pump and airless bottle expose the product differently, so changing the container later can mean repeating part of that work.
5. Will the ingredient list on the box match the factory’s list?
Not word for word. The factory’s list uses Japanese labelling names, while most export labels use INCI names. The list must be converted and checked, and extracts are listed with their solvents unless the solvent does not remain in the product.