Fermented or aged black garlic,
does it really help with Improved ALT and AST and protection of liver function in healthy adults?
research showsFermented black garlic is rated D for improving ALT and AST and protecting liver function in healthy adults. The dedicated double-blind trial enrolled only 40 people for 12 weeks; the between-group ALT change was borderline at P=.049, while AST was not significant at P=.099. Liver enzymes are surrogate markers, and the trial did not assess imaging, fibrosis, incident liver disease, or another clinical outcome. One small borderline surrogate result cannot establish clinical liver protection.
ads claimMarketing can expand S-allylcysteine content or a small ALT change into detoxification, repair of liver injury, fatty-liver treatment, or comprehensive liver protection. The trial measured only borderline enzyme changes in healthy adults and did not test clinical liver disease improvement.
Useful facts when choosing a product
- Black garlic is produced by aging garlic under controlled heat and humidity, changing its color, flavor, and composition; S-allylcysteine content and processing differ among products.
- The fermented or aged black garlic in this verdict is not equivalent to an individually recognized probiotics-fermented garlic extract or to ordinary garlic powder.
- Gastrointestinal discomfort, heartburn, odor, or garlic allergy can occur.
- People using anticoagulants or antiplatelet medicines, or preparing for surgery, should discuss potential bleeding interactions of concentrated garlic supplements with a clinician.
What the research actually shows
Kawasaki and colleagues assigned 40 healthy Japanese adults to a fermented black garlic supplement or placebo and tested blood at six and 12 weeks. The between-group 12-week ALT change had P=.049, whereas AST had P=.099; the trial was registered as UMIN000024771. Meta-analysis of general garlic supplements combines different preparations and populations and cannot replace replication specific to aged black garlic. Corpus item 595 concerns an individually recognized probiotics-fermented garlic extract with a distinct process, while item 076 addresses blood pressure and cholesterol from garlic; neither is this ingredient-claim pair.
Why this is classified as D (25)
Dedicated evidence consists of one 40-person, 12-week trial with borderline ALT at P=.049 and null AST at P=.099. It measured surrogate enzymes without clinical liver outcomes or replication, giving D with 25 points.
Counterpoint. Use as food is possible, but lowering a normal enzyme value is not synonymous with liver protection. Abnormal liver tests require cause-directed evaluation and established care.
Rejudgment record. New verdict — Applied D for small, borderline surrogate evidence because the dedicated 40-person, 12-week aged-black-garlic trial found ALT at P=.049, null AST at P=.099, no clinical liver outcome, and no independent replication; evidence from other garlic preparations was not transferred
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 |
|---|---|---|
| Improved ALT in healthy adults | D | Only one 40-person trial provides a borderline P=.049 signal. |
| Improved AST in healthy adults | D | The dedicated trial was not significant at P=.099. |
| Clinical liver-function or liver-disease improvement from fermented black garlic | D | There is no evidence assessing imaging, fibrosis, or clinical events beyond enzymes. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Kawasaki Y et al. 2017 | Placebo-controlled double-blind randomized trial | 12 | Inadequately reported; product-specific nutrition trial | Blood liver enzymes including ALT and AST | Between-group ALT change P=.049 and AST P=.099; no clinical liver-disease outcome. | Only dedicated, borderline surrogate trial |
| Panjeshahin A et al. 2020 | Systematic review and meta-analysis of randomized trials | Academic research as reported | ALT and AST | General garlic-supplement findings were mixed across preparations and populations and do not replicate aged black garlic specifically. | Indirect and formulation-heterogeneous |
Receipt — 3 References
All 3 cited sources were verified for existence at the original page (as of 2026-07-23).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-07-23 · Corrections: none
Cite this verdict
[Chamgap] Fermented or aged black garlic x Improved ALT and AST and protection of liver function in healthy adults — Evidence Grade D·25. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/liver/fermented-black-garlic-alt-ast-liver-function/ · 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.