White Kidney Bean Extract: Carb Blocker Evidence
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White Kidney Bean Extract (Phaseolus vulgaris): half-life, strengths and approval status

Amounts studied · Approval status · Half-life notes

What is white kidney bean extract?

White kidney bean extract (Phaseolus vulgaris) is sold as a "carb blocker" because in the lab it blocks alpha-amylase, an enzyme that breaks down starch. Trials of it for weight loss have mixed results: a 2011 review found it lowered body fat a little but did not change body weight overall.

Also known as: Phaseolus vulgaris, Phase 2, starch blocker, carb blocker.

Amounts studied

Trials used about 445 mg once a day before a carbohydrate-rich meal, 1,500 mg twice a day with meals, and 1,000 mg three times a day before meals (ODS). The 2011 review covered 445 to 1,500 mg a day for 4 to 13 weeks. These are study protocols, not a recommendation.

Approval status and how it is used

It is sold in the US as a dietary supplement. Under the 1994 dietary supplement law (DSHEA), FDA does not approve dietary supplements before they are marketed, and the maker, not FDA, is responsible for safety and labeling. How it differs from GLP-1 medicines: semaglutide (Wegovy) and tirzepatide (Zepbound) are prescription drugs whose FDA labels include reducing excess body weight and keeping it off long term in adults with obesity, or with overweight and a weight-related condition, alongside diet and exercise. White kidney bean extract is not an FDA-approved drug for weight loss.

What studies show: a 2011 meta-analysis of 6 trials (247 people) found about 1.86 kg more body fat loss than placebo but no significant difference in body weight, and said all the trials had serious design flaws (Onakpoya 2011). In an 8-week US trial in adults with obesity, 1,500 mg twice a day did not lead to significantly more weight loss than placebo (Udani 2004). After that review, a 12-week trial in 123 adults on a mildly reduced-calorie diet found 2.91 kg of weight loss with the extract IQP-PV-101 (3,000 mg a day) versus 0.92 kg with placebo (Grube 2014). ODS calls the results inconsistent.

Safety: ODS lists headaches, soft stools, flatulence and constipation, and no serious side effects in trials, but no trial lasted longer than 13 weeks. FDA warns that many products sold for weight loss, including supplements and teas, are likely to contain dangerous hidden drug ingredients, and that its public list of such products covers only a small fraction of them.

White kidney bean extract half-life and time to peak

  • Half-lifeNot listed
  • Time to peak (Tmax)Not listed

White kidney bean extract is meant to act in the gut on starch digestion (ODS), and we could not find a published half-life or time to peak, so we do not list one.

How to track white kidney bean extract in Dose Track

  1. Add white kidney bean extract as a custom compound. Start typing its name and Dose Track fills in the details from its research library for you to check, and it sits next to everything else you take.
  2. Log each dose when you take it so your history shows exactly what you took and when.
  3. Set reminders on your own schedule, whether that is daily, weekly or every few days.
  4. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

How Dose Track handles peptides · Reconstitution calculator · Half-life calculator

African Mango (Irvingia gabonensis)Irvingia gabonensis, IGOB131 Chitosandeacetylated chitin White Mulberry Leaf Extractmulberry leaf extract, Reducose AcarbosePrecose · half-life about 2 hours

Frequently asked questions

What is the half-life of white kidney bean extract?+
White kidney bean extract is meant to act in the gut on starch digestion (ODS), and we could not find a published half-life or time to peak, so we do not list one.
Do carb blockers work for weight loss?+
The evidence is mixed. A 2011 meta-analysis of white kidney bean extract found a small drop in body fat but no significant change in body weight, and said the trials were poor quality. A later 12-week trial found about 2 kg more weight loss than placebo.
What are the side effects of white kidney bean extract?+
ODS lists headaches, soft stools, gas and constipation. No serious side effects were reported, but no trial lasted longer than 13 weeks.
Can I track white kidney bean extract in Dose Track?+
Yes. White kidney bean extract is in Dose Track's research library, so when you add it as a custom compound its details are filled in for you to check. You can then log each dose next to your other compounds, set reminders on your own schedule, and see your history next to your lab results. Your log is stored on your phone and no account is needed. Data only leaves it for features you choose, like AI answers and lab reading.

Sources

  1. NIH Office of Dietary Supplements. Dietary supplements for weight loss, fact sheet for health professionals (updated May 18, 2022).
  2. Onakpoya I, et al. The efficacy of Phaseolus vulgaris as a weight-loss supplement: a systematic review and meta-analysis of randomised clinical trials. Br J Nutr. 2011;106(2):196-202.
  3. Udani J, Hardy M, Madsen DC. Blocking carbohydrate absorption and weight loss: a clinical trial using Phase 2 brand proprietary fractionated white bean extract. Altern Med Rev. 2004;9(1):63-69.
  4. Grube B, et al. Weight reduction and maintenance with IQP-PV-101: a 12-week randomized controlled study with a 24-week open label period. Obesity. 2014;22(3):645-651.
  5. FDA. Weight loss product notifications (medication health fraud), accessed October 28, 2026.
  6. Wegovy (semaglutide) prescribing information, section 1 (Indications and usage). DailyMed.
  7. Zepbound (tirzepatide) prescribing information, section 1 (Indications and usage). DailyMed.
  8. FDA. Questions and answers on dietary supplements.

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