Last verified: 2 days ago
White Kidney Bean
Also known as: Phaseolus vulgaris, WKBE, Phase 2, Phaseolean, starch blocker, alpha-amylase inhibitor
Evidence under review. — Not yet rated
Starch-blocking extract shown in multiple trials to modestly reduce body weight and fat mass.
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What it does
White kidney bean extract is a concentrated form of a protein found in white kidney beans that blocks alpha-amylase, the enzyme your body uses to digest starchy carbohydrates. By slowing starch...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
700-3000 mg daily (split before meals)
What the Science Says
White kidney bean extract is a concentrated form of a protein found in white kidney beans that blocks alpha-amylase, the enzyme your body uses to digest starchy carbohydrates. By slowing starch digestion, it reduces how many carbohydrate calories your body absorbs, which can lead to modest weight and fat loss over time. Multiple clinical trials and a meta-analysis of 8 studies found it reduced body weight by about 1.6 kg and fat mass by about 1.2 kg compared to placebo, with doses ranging from 700 to 3000 mg per day taken before meals.
What It Doesn't Do
Won't replace diet and exercise — all positive trials used calorie restriction alongside the supplement. Doesn't significantly lower blood sugar, triglycerides, or insulin levels based on current evidence. Not a fat burner — it only slows starch digestion, so it has little effect if your diet is low in carbs. No proven benefit for PCOS or hormonal conditions in humans yet. Won't work if you take it after eating.
Evidence-Based Benefits
Reduces body weight by roughly 1.6 kg more than placebo in overweight adults over 6–12 weeks.
Moderate EvidenceEffective at: 700-3000 mg daily before meals
Supporting studies (click to view on PubMed):
Reduces fat mass by about 1.2 kg compared to placebo while preserving lean muscle.
Moderate EvidenceEffective at: 700-3000 mg daily before meals
Supporting studies (click to view on PubMed):
Reduces waist and hip circumference in overweight adults taking it before meals.
Moderate EvidenceEffective at: 700-3000 mg daily before meals
Supporting studies (click to view on PubMed):
High doses (3000 mg powder form) can meaningfully lower the glycemic index of starchy foods like white bread.
Weak EvidenceEffective at: 3000 mg powder form with meal
Supporting studies (click to view on PubMed):
Absorption & Bioavailability
Unknown — the active component (alpha-amylase inhibitor protein) works locally in the gut rather than being absorbed systemically, so traditional bioavailability measures don't apply. Effectiveness depends on timing relative to meals.
Red Flags to Watch For
- Must be taken 30 minutes before carbohydrate-rich meals to have any effect — timing is critical
- Raw or undercooked white kidney beans contain toxic lectins; only use properly processed extracts
- Most trials are short-term (30–84 days); long-term safety and efficacy data are limited
- Many products on the market are not standardized for alpha-amylase inhibitor activity — potency varies widely
- Gastrointestinal side effects (gas, bloating) are possible due to undigested starch reaching the colon
Products Containing White Kidney Bean
See how White Kidney Bean is used in these analyzed products:
Frequently Asked Questions
What does White Kidney Bean do?
Starch-blocking extract shown in multiple trials to modestly reduce body weight and fat mass.
What is the effective dose of White Kidney Bean?
700-3000 mg daily (split before meals)
Is White Kidney Bean safe?
Must be taken 30 minutes before carbohydrate-rich meals to have any effect — timing is critical
What doesn't White Kidney Bean do?
Won't replace diet and exercise — all positive trials used calorie restriction alongside the supplement.
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-11-07