Whole koji amazake,
does it really help with More defecation days and bowel movements?
research showsThe grade is C with 50 points. A three-week trial randomized 44 healthy adults with relatively infrequent bowel movements, 22 per group, and analyzed all of them. A daily 118 g serving increased weekly defecation days by about 1.27 more days than control. UMIN000038520 was prospective and its primary outcome matched the paper, but this remains one small, short manufacturer-related trial without independent replication.
ads claimThe result cannot identify Aspergillus-derived cell material or any single fermented carbohydrate as the cause. The intervention was whole amazake, not an isolated component.
Useful facts when choosing a product
- The 118 g product contained 302±15.5 mg Aspergillus-derived cell material and fermented carbohydrates.
- A 118 g serving supplied 127.4 kcal, 29.7 g carbohydrate, and 29.5 g available carbohydrate.
- Ash was reported as 0.1 g, but it cannot be converted to sodium; serving sodium and its percentage of the Daily Value were unconfirmed.
- Histamine, tyramine, nitrite, and N-nitroso compounds in the test product were unconfirmed.
- It is a Japanese traditional food, but an exact first date was not confirmed.
- Verdict 099 is C with 52 points for a strain isolated from kimchi, verdict 055 is D with 34 points for isolated nattokinase, and verdict 407 is C with 48 points for isolated poly-gamma-glutamic acid. Those isolated interventions are not whole koji amazake containing mold-derived material, sugars, and rice substrate together.
What the research actually shows
The 2021 Journal of Fungi paper by Kurahashi A et al. was checked against UMIN000038520. It randomized 44 participants equally, analyzed all, and used 118 g daily. Registration preceded enrollment and the registered primary outcome of stool frequency matched the paper. The paper's Funding section says there was no external funding, while its conflict-of-interest section states support from Hakkaisan Brewery and employee relationships; both differing statements are material.
Why this is classified as C (50)
Between-group differences in defecation days and counts were significant, and the approximate standardized effect exceeded the conventional medium threshold. Prospective registration and primary-outcome concordance were confirmed, but this is one 44-person, three-week manufacturer-related trial, giving C with 50 points.
Counterpoint. Independent investigators should replicate it with a longer, prospectively registered protocol.
Rejudgment record. Cross-check applied — Approximate between-group confidence intervals and standardized effect calculated from reported means and standard deviations, with sample, prospective registration, primary-outcome concordance, and the differing Funding and conflict-of-interest statements verified
| Endpoint | P | Patient-reported treatment goal - the symptom is the goal |
| Replication | R1 | Single confirmatory trial |
| Independence | I0 | Evidence comes only from manufacturer studies |
| Effect size | E+ | Meets the clinically important threshold |
The scoring table and the verdict agree (C).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Koji amazake contains mold-derived cell material and fermented carbohydrates | ? | This is a measured composition fact, not a graded clinical outcome. |
| A 118 g serving of koji amazake increases defecation days and frequency | C | One short manufacturer trial was positive without independent replication. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Study 1 | Double-blind randomized placebo-controlled trial, three weeks | 44 | Funding section reports no external funding; conflict-of-interest section states Hakkaisan Brewery support and employee relationships | Weekly defecation days and bowel-movement frequency | Defecation-day difference +1.27, approximate 95% CI +0.42 to +2.12; bowel-movement difference about +1.69, approximate 95% CI +0.25 to +3.13 | Positive direct patient-centered outcomes in one short manufacturer-related trial |
Receipt — 3 References
All 3 cited sources were verified for existence at the original page (as of 2026-08-02).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-02 · Corrections: none
Cite this verdict
[Chamgap] Whole koji amazake x defecation frequency — Evidence Grade C·50. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/gut/whole-koji-amazake-defecation-frequency/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.