White Kidney Bean Extract
Also known as: Phaseolus vulgaris extract, Phase 2, Phase 2 Carb Controller, alpha-amylase inhibitor, phaseolamin
White kidney bean extract is a protein fraction of Phaseolus vulgaris that inhibits alpha-amylase, the enzyme that digests starch. It is sold as a carb blocker for weight management and is taken before starchy meals. A systematic review of six RCTs found a small, statistically significant reduction in body fat but a non-significant difference in body weight, and rated the trials as methodologically weak. Branded Phase 2 is standardized for amylase-inhibiting activity.
Research summary
Phaseolamin binds pancreatic alpha-amylase, reducing the fraction of dietary starch converted to absorbable glucose.
Dosage
Daily amounts, of extract.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| — | 500–1,500 mg | — | — |
500–1,500 mg per day, taken as 500 mg before each starchy meal. Effect is meal-specific, so timing matters more than daily total. Trials varied in dose and duration and quality was low.
Standardization: standardized to alpha-amylase inhibiting units (supplier dependent; Phase 2 specifies minimum AAIU/g)
Source material: bean (seed) extract
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Bland protein powder; capsules, tablets, and chewables are common. Heat during processing can denature the inhibitor, so avoid hot gummy cooking without supplier confirmation.
Formulation notes
May modestly lower post-meal glucose; consider with diabetes medications. Heat-sensitive activity.
Sources
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