Chlorella is one of the oldest supplement ingredients Japan makes at scale — tablet and powder products made from the freshwater green alga have been on Japanese shelves for decades, long enough for the health ministry to have set processing standards for them in 1981. Brands abroad ask for a Japan-made chlorella product because of that long production history.
Chlorella also comes with two cautions that a brand should build into the specification from day one: its vitamin K content, and a rare but documented photosensitivity reaction. This guide sets out the evidence, the cautions, and what to decide before a Japan-made product.
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 chlorella product made in Japan? We check the full formula against Japanese food law first. See Japan-made supplement OEM.
What the research shows
Small human trials report changes in immune markers after several weeks of chlorella, while evidence for other uses is more mixed.
| Study | Design/What was analysed | Reported result |
|---|---|---|
| Randomised, double-blind, placebo-controlled trial, Nutrition Journal 2012;11:53 (PMID 22849818, PMC3511195) | 60 healthy adults in Korea randomised and 51 completed; 5 g/day chlorella tablets or placebo for 8 weeks; natural killer (NK) cell cytotoxic activity and serum cytokines | NK cell activity and serum interferon-γ and interleukin-1β increased significantly more in the chlorella group than in the placebo group |
| Randomised, blinded, crossover study, Nutrition Journal 2011;10:91 (PMID 21906314, PMC3182968) | 15 healthy men, 4 weeks of chlorella tablets versus placebo tablets, separated by a washout; salivary secretory immunoglobulin A (SIgA) | Salivary SIgA concentration and secretion rate significantly increased after chlorella, not after placebo |
| Meta-analysis of randomised controlled trials, Clinical Nutrition 2018;37(6 Pt A):1892–1901 (PMID 29037431) | 19 trials, 797 subjects with differing health status; lipid, blood-pressure, blood-glucose and body-weight markers | Total cholesterol (−9.09 mg/dL), LDL cholesterol (−8.32 mg/dL), systolic blood pressure (−4.51 mmHg), diastolic blood pressure (−1.64 mmHg) and fasting blood glucose (−4.23 mg/dL) fell significantly versus control; triglycerides, HDL cholesterol and BMI did not change significantly; several effects were seen mainly in people with unhealthy baseline values |
Both immune-marker trials were small and short (weeks, not months), used a single dose level, and measured laboratory markers rather than infection rates or illness days. The salivary SIgA trial was funded by a chlorella supplement company that also supplied the test tablets. The meta-analysis pooled trials in people with differing health status, and its authors called for more precise trials; a change in a laboratory marker is not the same as a proven clinical benefit, and none of these findings support a disease-related claim for a product.
Checked against the published abstracts on 13 October 2026.
What Japanese products say
Chlorella is typically sold in Japan as an ordinary food supplement, not through a system that assigns it a specific notified function.
Long-established ingredients with a food history like chlorella are commonly formulated and sold in Japan without a Foods with Function Claims notification naming chlorella itself as the functional component; some chlorella-containing products carry other, separately notified functional ingredients alongside it. A brand should not assume a Japanese notified function exists for chlorella and should check the current notification database for any specific claim it wants to make.
A 1981 notice from Japan’s Ministry of Health and Welfare (now the Ministry of Health, Labour and Welfare) states that photosensitivity from eating processed chlorella products is known, and sets upper limits for pheophorbide, a chlorophyll breakdown product, together with heat treatment of the raw powder, minimal contact with water and organic solvents, and storage away from direct sunlight, heat and humidity. Processing and quality control of the raw material are the standard way this is managed in production.
💬 Need the vitamin K and photosensitivity cautions written into your label copy correctly? We prepare the documentation with the manufacturing specification. Tell us your market.
Wording that stays on safe ground
Describe chlorella by its composition and what has been studied, and carry the vitamin K caution rather than a cholesterol or immunity claim.
| Safer wording | Wording to avoid |
|---|---|
| ”Contains chlorella, studied for immune-marker changes in small trials" | "Boosts immunity” or “prevents infection" |
| "May interact with vitamin K antagonist medicines such as warfarin — advise your customer to check with a doctor” | Silence on the vitamin K content |
| ”Contains chlorella” with the amount per serving | Cholesterol-lowering or blood-marker claims for the product |
How chlorella is formulated
Chlorella is a dried algae powder, so it is dosed in grams rather than milligrams and formulated mainly as tablets, granules or loose powder.
| Dosage form | Why brands choose it | What to weigh up |
|---|---|---|
| Tablet | The traditional Japanese format; convenient for a multi-gram daily dose split into several tablets | Number of tablets needed for a multi-gram serving |
| Granule or powder | Mixes into drinks; matches the multi-gram dose in one measure | Strong colour, taste and smell |
| Hard capsule | Masks taste and smell | More capsules needed for the same gram dose than a tablet-only format |
Decisions that shape the specification:
- Cell-wall processing. Chlorella’s cell wall is broken down in processing to improve digestibility; ask the supplier for their processing method and any quality data on the finished material.
- Amount per serving. Published trials used around 5 g/day; match your amount to any study you intend to cite, and disclose it on the label.
- Vitamin K disclosure. Chlorella’s vitamin K content is a documented reason it can reduce the effect of warfarin and similar anticoagulant medicines. A caution statement for people on such medicines is a standard, honest addition regardless of destination-market label rules.
- Quality control for chlorophyll breakdown products. Raw material sourcing and processing conditions affect pheophorbide levels; ask the supplier for their quality specification.
- Your market’s status for chlorella. Confirm its status as a food ingredient in your own market before you commit to a formula.
The check that comes first
Every ingredient must be permitted in foods in Japan, or a Japanese factory cannot make the product.
Chlorella itself has a long food-use history in Japan. Where a formula adds other actives — for eye comfort, energy or antioxidant positioning, for example — each of those needs its own check against Japanese food law. See the Japan-made supplement OEM page, and compare with our astaxanthin guide for another algae-derived ingredient.
Before you ask for a quotation
A factory can quote accurately once the amount, the form, the processing and the packaging are fixed.
- Chlorella amount per serving and servings per pack
- Dosage form (tablet, granule, powder, capsule)
- Cell-wall processing method
- Companion ingredients and their amounts
- Packaging
- Countries you will sell in, and chlorella’s status there
- First order and annual volume
💬 Ready to design a Japan-made chlorella product? Send us the concept — amount, form, companion ingredients and the countries you will sell in.
Frequently asked questions
1. Does chlorella have strong evidence for immune benefits?
Two small, short trials found changes in immune markers — NK cell activity and cytokines in one, salivary SIgA in the other — after several weeks of chlorella. These are laboratory-marker findings from small studies, not proof of fewer illnesses, so describe chlorella as studied for immune-marker changes rather than as an immunity treatment.
2. Can chlorella affect warfarin or other blood-thinning medicines?
Yes. A published case report describes a patient on warfarin whose anticoagulant control weakened after starting chlorella, attributed to chlorella’s vitamin K content. A caution for people on such medicines belongs on the label regardless of market.
3. What is the photosensitivity concern with chlorella?
Japan’s health ministry noted in 1981 that photosensitivity from eating processed chlorella products is known, and set limits for pheophorbide, a chlorophyll breakdown product. It is managed through raw-material quality control, heat treatment, processing and storage conditions.
4. Does chlorella lower cholesterol?
A 2018 meta-analysis of 19 trials found significant reductions in total and LDL cholesterol, blood pressure and fasting blood glucose, with no significant change in triglycerides, HDL or BMI, in people with differing health status. This is evidence about the ingredient in the research literature; it should not be turned into a cholesterol, blood-pressure or blood-sugar claim for a food product.
5. Which dosage form suits chlorella?
Tablets and granules are the traditional Japanese formats, because chlorella is dosed in grams rather than milligrams. Capsules are used too, mainly to mask taste and smell, at the cost of more capsules per serving.
Sources: “Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of Natural Killer cell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial)”, Nutrition Journal 2012;11:53 (PMID 22849818, PMC3511195); “Salivary secretory immunoglobulin A secretion increases after 4-weeks ingestion of chlorella-derived multicomponent supplement in humans: a randomized cross over study”, Nutrition Journal 2011;10:91 (PMID 21906314, PMC3182968); “Effect of Chlorella supplementation on cardiovascular risk factors: A meta-analysis of randomized controlled trials”, Clinical Nutrition 2018;37(6 Pt A):1892–1901 (PMID 29037431); “[Warfarin therapy and chlorella]”, Rinsho Shinkeigaku 1995 (PMID 8777808); Ministry of Health and Welfare notice on processed chlorella products (8 May 1981), published by the Ministry of Health, Labour and Welfare. Checked on 13 October 2026.