White Kidney Bean Extract
Summary
White kidney bean extract contains alpha-amylase inhibitors that may slow starch digestion. A 2026 meta-analysis of 8 trials (543 adults) found about 1.6 kg more weight loss than placebo (grade B), but an earlier review judged the trials seriously flawed and the effect is below common thresholds for clinical importance. Most trials paired the extract with calorie restriction.
Key facts
- Inhibits alpha-amylase, the enzyme that digests starch, so fewer carbohydrate calories are absorbed[3][1]
- −1.62 kg versus placebo (95% CI −1.99 to −1.25) across 8 RCTs and 543 adults[1]
- A 2011 review of 6 RCTs found a non-significant weight difference (−1.77 kg) and serious methodological flaws[2]
- A 2020 herbal-medicine meta-analysis found the weight loss statistically but not clinically significant (threshold 2.5 kg)[7]
- 5 graded human outcomes on this page
- October 13, 2026
How it works
ProposedBean extracts standardized to alpha-amylase-inhibitor activity block starch-digesting enzyme activity in vitro. In people, the extract given with a starchy meal lowered post-meal glucose and insulin rises in short tests, consistent with slower starch digestion; the size of the effect in daily eating is uncertain.[3][5][6]
What the human research says
Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.
At a glance: strongest evidence per outcome
| Outcome | Grade | Effect | Strongest evidence | Rows |
|---|---|---|---|---|
| Weight | Grade B | Improved | Meta-analysis of 8 trials · n = 543 · 2026 | 3 rows |
| Blood sugar | Grade D | Mixed | Crossover RCT · n = 13 · 2009 | 2 rows |
Every graded row
| Outcome | Effect | Grade | Best evidence | PMID |
|---|---|---|---|---|
| Body weight and fat mass in overweight and obesity | Improved | Grade B | Meta-analysis · n = 543 · 2026 Adults with overweight or obesity (8 RCTs) Form: White kidney bean extracts (various standardized products) · Dose: Varied by trial · Duration: Varied by trial Weight fell 1.62 kg more than placebo, with reductions in BMI (−0.58), fat mass (−1.17 kg), waist (−1.58 cm) and hip circumference; fasting glucose, triglycerides and insulin did not differ. No serious related adverse events. | 42066439 (opens PubMed)Source [1] |
| Weight and fat loss during calorie restriction (Phase 2 extract) | Improved | Grade C | RCT · n = 81 · 2024 Adults with overweight or moderate obesity on a calorie-restricted diet Form: Phase 2 aqueous white kidney bean extract standardized to alpha-amylase-inhibitor activity · Dose: 700 mg or 1,000 mg three times daily, 30 minutes before meals · Duration: 12 weeks Body weight, fat mass, BMI, waist and hip circumference fell more than with placebo, in a dose-dependent manner. | 38830962 (opens PubMed)Source [3] |
| Weight and body fat in overweight and obesity (Phaseolean extract) | Improved | Grade C | RCT · n = 62 · 2024 Adults with overweight or obesity (India) Form: Phaseolean standardized water extract · Dose: 500 mg or 1,000 mg before each of three meals (1.5 or 3 g/day) · Duration: 45 days Weight fell about 2.1 kg (1.5 g/day) and 1.9 kg (3 g/day) versus 0.13 kg on placebo (P < 0.01), with lower BMI, body fat and circumferences; no adverse effects. | 39170208 (opens PubMed)Source [4] |
| Glycaemic index of white bread | Mixed | Grade D | Crossover RCT · n = 13 · 2009 Healthy adults Form: Phase 2 extract as capsules or powder mixed into bread · Dose: 1,500, 2,000 or 3,000 mg with the meal · Duration: Single test meals Only 3,000 mg of powder significantly lowered the glycaemic index (by 34%); capsules at any dose and lower powder doses did not. | 19860922 (opens PubMed)Source [5] |
| Post-meal glucose, insulin and appetite | Improved | Grade D | Crossover RCT · n = 12 · 2013 Healthy volunteers Form: Purified, standardized Phaseolus vulgaris extract · Dose: 100 mg with a mixed meal · Duration: Single test meals Glucose, insulin and C-peptide rises were smaller than with placebo, ghrelin did not rebound, and desire to eat was lower over 3 hours. | 23046862 (opens PubMed)Source [6] |
Forms
| Form | Elemental % | Absorption (human data) | GI tolerance | Studied for |
|---|---|---|---|---|
| Phase 2 white kidney bean extract | Varies[3] | Acts in the gut on starch digestion; capsules lowered the glycaemic index of bread less than powder mixed into the food.[5] | Described as safe in the 12-week trial.[3] | Weight loss (2.1–3 g/day) and glycaemic index |
| Other standardized extracts (Phaseolean, purified PVE) | Varies[4][6] | Acts in the gut; no systemic absorption data on this page.[6] | No adverse effects reported over 45 days at 1.5–3 g/day.[4] | Weight loss and post-meal glucose |
Studied doses
Doses studied in human trials ranged from 100 mg with a single test meal to 3 g/day (500–1,000 mg before each of three meals) for 45 days to 12 weeks.[6][3][4]
Interactions
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
None found in our sources.
Who should be careful
- Diabetes medicines
- Single-meal studies showed lower post-meal glucose and insulin; the trials give no data on combining the extract with glucose-lowering drugs.[6][5]
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.
How to read the label
- Check standardizationTrials used extracts standardized to alpha-amylase-inhibitor activity (Phase 2) or branded water extracts; an unstandardized bean powder is not the tested product.[3][4]
- Timing used in trialsWeight trials gave the extract before each of three meals, 30 minutes ahead in the Phase 2 study.[3][4]
- Label dose vs studied doseWeight trials used 1.5–3 g/day in three doses; a single 500 mg capsule a day is below the studied range.[3][4]
Cost per studied dose, without the sales pitch
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Cost per studied dose
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Frequently asked questions
Does white kidney bean extract block carbs?
It inhibits the starch-digesting enzyme alpha-amylase. In meal tests it lowered post-meal glucose and insulin, but capsules had weaker effects than powder mixed into food.[3][5][6]
Does white kidney bean extract help weight loss?
A 2026 meta-analysis of 8 trials found about 1.6 kg more loss than placebo. An earlier review called the trials seriously flawed, and another judged the effect not clinically meaningful.[1][2][7]
How much was studied?
Weight trials used 500–1,000 mg before each of three meals (1.5–3 g/day) for 45 days to 12 weeks.[3][4]
When was it taken in trials?
Before meals; the Phase 2 trial gave it 30 minutes before each meal.[3]
Sources
- [1]White kidney bean extract reduces body weight and adiposity with acceptable safety in adults with overweight and obese: a systematic review and meta-analysis.. Nutr Res, 2026. meta-analysis
- [2]The efficacy of Phaseolus vulgaris as a weight-loss supplement: a systematic review and meta-analysis of randomised clinical trials.. Br J Nutr, 2011. meta-analysis
- [3]Proprietary alpha-amylase inhibitor formulation from white kidney bean (Phaseolus vulgaris L.) promotes weight and fat loss: a 12-week, double-blind, placebo-controlled, randomized trial.. Sci Rep, 2024. RCT
- [4]A randomized, double-blinded, placebo-controlled, single-center, comparative study evaluating Phaseolean® safety and efficacy in overweight/obese participants.. Heliyon, 2024. RCT
- [5]Lowering the glycemic index of white bread using a white bean extract.. Nutr J, 2009. crossover-RCT
- [6]Phaseolus vulgaris extract affects glycometabolic and appetite control in healthy human subjects.. Br J Nutr, 2013. crossover-RCT
- [7]Effectiveness of herbal medicines for weight loss: A systematic review and meta-analysis of randomized controlled trials.. Diabetes Obes Metab, 2020. meta-analysis
What changed
- Strict second-pass self-review (no separate reviewer could be dispatched for this batch): all 7 PMIDs re-verified by NCBI esummary (titles and years match the record) and efetch checked for retraction, expression-of-concern and erratum flags (none flagged); every evidence row, key fact, form, dose, label line, FAQ and insight re-read against its abstract, and against PMC full text where the dose or count lives. Fixes: removed an unverified trial country. Page set indexable.
- First draft. Every PMID checked against NCBI E-utilities esummary (title and year from the record) and abstracts read for each cited row. A 2014 IQP-PV-101 trial was left out because its PubMed record carries an erratum notice and its abstract lacks a participant count. No NIH ODS or NCCIH fact sheet covers white kidney bean extract.