Reishi (Ganoderma lucidum, also called lingzhi or mannentake) has centuries of use in East Asian herbal traditions, and Japan’s own reishi cultivation and extraction industry gives brands abroad a reason to ask for a Japan-made version by name.
This guide is for brand owners planning a reishi product made in Japan. It sets out what recent human trials actually found, keeps cancer research in its proper place as a research question rather than a product claim, explains reishi’s food status in Japan, and covers what to fix before asking for a quotation.
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 reishi product made in Japan? We check the full formula against Japanese food law first. See Japan-made supplement OEM.
What the research shows
A 2025 GRADE-assessed systematic review found very low-quality evidence for reishi across every health outcome it examined, and a separate Cochrane review found insufficient evidence to support reishi as a cancer treatment.
| Study | Design/What was analysed | Reported result |
|---|---|---|
| Systematic review and meta-analysis, Food Science & Nutrition 2025 (PMID 40510787) | 17 randomised controlled trials, 971 participants, reishi doses of 200–11,200 mg/day for 1–24 weeks, in healthy, at-risk and chronic-disease populations | Significant reductions in BMI, creatinine, glutathione peroxidase and heart rate; no significant effect on body fat, waist circumference, blood pressure, fasting glucose, lipid profile, inflammatory markers or liver enzymes; GRADE certainty was very low for every outcome |
| Randomised, double-blind, placebo-controlled trial, Foods 2023 (PMID 36766186) | 84 days of reishi beta-glucan or placebo in healthy adults aged 18–55 | Significant increases in CD3+, CD4+ and CD8+ T-lymphocyte percentages, an improved CD4/CD8 ratio, higher natural killer cell counts, and higher serum IgA and NK-cell cytotoxicity versus placebo; no significant change in kidney or liver markers |
| Cochrane systematic review, Cochrane Database of Systematic Reviews 2016 (PMID 27045603) | 5 randomised controlled trials of reishi alongside chemotherapy/radiotherapy in patients with a cancer diagnosis | Reishi combined with chemo/radiotherapy was associated with a higher tumour response rate than chemo/radiotherapy alone, and with increased CD3, CD4 and CD8 percentages; the authors found the trial quality generally unsatisfying and concluded there was not sufficient evidence to justify reishi as a first-line cancer treatment |
Three caveats worth keeping in view:
- Certainty. The 2025 review graded every outcome it studied as very low-quality evidence under the GRADE framework, even where a result reached statistical significance.
- Population and context. The Cochrane review studied people already diagnosed with and being treated for cancer, alongside conventional chemotherapy or radiotherapy. That is a fact about the research population, not a basis for a product claim, and it does not describe how reishi behaves in healthy people taking it on its own.
- Size. The immune-cell trial was a single study in healthy adults. One trial does not establish an effect on its own.
Checked against the published abstracts on 25 September 2026.
What Japanese products say
Reishi is sold in Japan as a general food — extracts, powders, tablets and teas — reflecting its status as an ingredient not treated as a medicine unless a medicinal claim is attached to it.
Japan’s food-drug classification system (食薬区分) keeps two lists: substances treated exclusively as medicines, and substances not judged to be medicines unless the product claims a medicinal effect. Reishi fruiting body sits on the second list, alongside its common names lingzhi and mannentake. That status is why reishi has long been sold across Japan as a general food ingredient, through the same retail and health-food channels as other traditional botanicals, rather than through pharmacies as a medicine.
Being food-usable is a different question from carrying a notified function. Describing reishi with a specific function under Japan’s Foods with Function Claims system requires its own notification and its own supporting evidence for that exact product — a separate step from the ingredient’s basic food status.
💬 Need an evidence summary for your regulatory adviser that separates Japanese food status from independent research findings? We prepare it with the manufacturing documents. Tell us your market.
Wording that stays on safe ground
Describe reishi by what has been studied and how certain that evidence is, never by a disease it might affect.
| Safer wording | Wording to avoid |
|---|---|
| ”Studied for immune cell counts in healthy adults” | Any cancer-related claim, or “treats”, “fights” or “cures” anything |
| ”Contains reishi extract” with the amount per serving | ”Clinically proven” without naming the study and its GRADE-rated certainty |
| ”Traditional ingredient, now studied in human trials” | Implying the cancer research applies to a product taken by healthy people |
How reishi is formulated
Reishi’s bitter, woody flavour and its use as an extract rather than a raw material push most Japanese products toward capsules, tablets or concentrated powders.
| Dosage form | Why brands choose it | What to weigh up |
|---|---|---|
| Hard capsule | Masks the bitter taste, simple manufacturing | Suits standardised extract powders |
| Tablet | Familiar format, easy dosing | Binder choice affects disintegration of dense extract powders |
| Powder or granule | Fits into drinks and combination products | Bitterness affects taste work |
| Liquid extract | Traditional format, faster absorption claims avoided | Alcohol or glycerine base affects labelling and market rules |
Decisions that shape the specification:
- Part of the mushroom and extraction method. Fruiting body and mycelium extracts differ in composition. Ask the supplier for the part used, the extraction solvent and the standardised marker compound (commonly polysaccharides or triterpenes) with its guaranteed percentage.
- Amount per serving. Trial doses in the 2025 review ranged from 200 mg to over 11,000 mg per day; match your amount to a specific study if you plan to cite one.
- Companion ingredients. Reishi is often combined with other mushrooms or adaptogenic botanicals in “healthy ageing” or “immune” formulas. Every companion ingredient needs its own check against Japanese food law.
- Your market’s status for reishi. Confirm reishi’s status as a food or supplement ingredient in each market you plan to sell in before committing 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.
Reishi extract itself is well established in Japanese foods. Companion botanicals in combination formulas are where a check most often turns up a problem. See the Japan-made supplement OEM page, and compare with our curcumin and NMN guides.
Before you ask for a quotation
A factory can quote accurately once the part used, the extraction standard, the amount and the form are fixed.
- Reishi part used (fruiting body or mycelium) and extraction/standardisation method
- Marker compound and guaranteed percentage
- Amount per serving and servings per pack
- Dosage form
- Companion ingredients and their amounts
- Countries you will sell in, and first order and annual volume
💬 Ready to design a Japan-made reishi product? Send us the concept — part used, extraction standard, amount and the countries you will sell in.
Frequently asked questions
1. Does reishi have strong clinical evidence behind it?
A 2025 GRADE-assessed systematic review of 17 trials rated the evidence as very low quality across every outcome it examined, even where a result reached statistical significance. Describe reishi as studied, not as proven.
2. Is reishi a cancer treatment?
No. A 2016 Cochrane review of trials in cancer patients found the evidence insufficient to justify reishi as a first-line cancer treatment. That research describes a population already receiving conventional cancer treatment, and it is not a basis for marketing a supplement product.
3. Does reishi affect the immune system?
One 2023 randomised trial in healthy adults found higher T-lymphocyte percentages and natural killer cell activity after 84 days of a reishi beta-glucan compared with placebo. It is a single study, so treat the result as preliminary.
4. Is reishi legally a food in Japan?
Reishi fruiting body sits on the list of substances Japan does not judge to be medicines unless a medicinal effect is claimed for the product, which is why it is widely sold as a food ingredient there.
5. Which part of the mushroom should I use?
Fruiting body and mycelium extracts differ in composition and in the studies behind them. Fix the part used and the standardised marker compound before asking for a quotation.
Sources: “The Nutritional Significance of Ganoderma lucidum on Human Health: A GRADE-Assessed Systematic Review and Meta-Analysis of Clinical Trials”, Food Science & Nutrition 2025 (PMID 40510787); “Evaluation of Immune Modulation by β-1,3; 1,6 D-Glucan Derived from Ganoderma lucidum in Healthy Adult Volunteers, A Randomized Controlled Trial”, Foods 2023 (PMID 36766186); “Ganoderma lucidum (Reishi mushroom) for cancer treatment”, Cochrane Database of Systematic Reviews 2016 (PMID 27045603); Japan Ministry of Health, Labour and Welfare 食薬区分における成分本質（原材料）の取扱いの例示. Checked on 25 September 2026.