| Ingredient | Studied for | Evidence in short | Usual form |
|---|---|---|---|
| Black ginger (Kaempferia parviflora) | Abdominal fat area and energy metabolism markers | Small trials: visceral fat and energy expenditure changes reported; independent replication still limited | Capsule, tablet, powder |
| Black vinegar (kurozu) | Body weight, BMI and visceral fat markers | One placebo-controlled trial positive; a second, smaller trial mixed and mostly in women | Drink, capsule, tablet |
| Capsinoids | Resting energy expenditure in healthy adults | Small trials show a measurable effect, concentrated in people with active brown fat | Capsule, softgel |
| Chitosan | Body weight in randomised trials of adults with overweight | Cochrane review: significant in pooled trials but minimal in higher-quality studies | Capsule, tablet |
| Forskolin (Coleus forskohlii) | Body composition in overweight and obese adults | Small randomised trials, mixed results; Japan requires a mandatory warning label | Capsule, tablet (Japan requires a specific warning label) |
| Garcinia cambogia (HCA) | Body weight in short randomised trials | Small, borderline-significant effect on weight; liver injury case reports exist and need review | Capsule, tablet |
| Green tea catechins | Body weight and body fat | Cochrane review: small, non-significant weight effect; Japanese trials too varied to pool | Tablet, capsule, powder, drink |
| Kudzu flower | Body weight and visceral fat area in adults with a higher BMI | One 12-week human trial; isolated compounds not yet tested in people | Capsule, tablet, powder |
| L-carnitine | Body weight and fat mass; energy metabolism during activity | Meta-analyses: modest weight and fat-mass effect that fades over time; no change in waist or body fat % | Tablet, capsule, drink, powder |
| MCT oil (medium-chain triglycerides) | Body weight and body composition versus long-chain fats | Meta-analysis: modest reduction in body weight and waist versus long-chain fat | Oil, powder stick, capsule |
| Quercetin | Body fat area and weight-management markers | Human results are mixed and depend on the glycoside form used | Tablet, capsule, drink, confectionery |
| White kidney bean extract | Body weight and body fat in randomised trials of adults with overweight | Mixed across meta-analyses; one found no significant weight effect, a newer one did | Capsule, tablet, powder |
Japan-made supplement OEM
Weight and metabolism supplements made in Japan
Japan’s Foods with Function Claims include many products notified for body fat, using ingredients such as green tea catechins, black ginger and kudzu flower isoflavones. The effects reported in trials are usually modest.
This category also has the clearest safety history in Japan, from liver cautions on high-dose green tea catechins to the 2006 white kidney bean incident and warning labels for designated ingredients such as Coleus forskohlii. The guides below cover both.
Weight and metabolism ingredients at a glance
What each ingredient has been studied for, how strong the published evidence is, and the usual dosage form.
“Studied for” describes research on healthy functions. It is not a claim that any product prevents, treats or cures a disease.
Before you choose a formula
Dosage form selection How tablet, capsule, softgel, powder, jelly, drink and gummy compare for a Japan-made supplement Export labelling and documents Japanese vs destination-market labels, over-labelling, country-of-origin rules, and factory documents to request Food-medicine boundary (食薬区分) How Japan's shoku-yaku kubun system decides food versus medicine status, and what it means for an export OEM order Starting a Japan-made supplement brand The steps from concept to launch for a brand that wants a supplement made in Japan
Frequently asked questions
How large are the effects of weight ingredients?
Usually small. For example, a Cochrane review found green tea preparations had a small effect on weight that was unlikely to be clinically important. Each guide gives the figures and sources.
Are there safety rules for weight ingredients in Japan?
Yes. Some ingredients, such as Coleus forskohlii, are designated ingredients in Japan with mandatory warnings and health-damage reporting. The guides explain each case.
How should a weight product be described?
By the modest, studied effect in the population tested, never as treating any condition. Your market’s rules set the exact wording.
Contact
Tell us what you want to buy or sell — in Vietnam or Japan
Selling into Vietnam or Japan, sourcing from either, or a product made under your own brand. One Japanese-managed team in Ho Chi Minh City, working in English, Japanese and Vietnamese.