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Amylase inhibitors


Related terms

Related Terms
  • AAI, alphaAI-1, alphaAI-2, arcelin-5, bean amylase inhibitors, Calorex, Fabaceae (family), Phase 2®, Phase 2 Starch Neutralizer®, phaseolamin, Phaseolus vulgaris extract, starch blockers, Starchex, wheat amylase inhibitor, wheat proteinaceous alpha-amylase inhibitors (alpha-AIs), white kidney bean extract.

  • Amylase is an enzyme that breaks down carbohydrates or starches in the body. Because of their purported ability to prevent starch breakdown and absorption, alpha amylase inhibitors have been used for weight loss. At this time, commercially available amylase inhibitors are extracted from wheat or white kidney bean (Phaseolus vulgaris).
  • In humans, amylase inhibitors have been shown to decrease intestinal absorption of carbohydrates by reducing intestinal amylase activity. However, there are few high-quality human studies that support the use of amylase inhibitors for any indication.

Evidence Table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. GRADE *

Amylase inhibitors have been shown to decrease levels of blood glucose. Large, well-designed studies are needed before a firm recommendation can be made.


Preliminary studies have shown that taking an amylase inhibitor with meals may lead to weight loss. However, well-designed clinical studies are needed in this area.

* Key to grades

A: Strong scientific evidence for this use
B: Good scientific evidence for this use
C: Unclear scientific evidence for this use
D: Fair scientific evidence for this use (it may not work)
F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory

The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

  • Antibacterial, antifungal, insecticide.


Adults (18 years and older)

  • Various doses of amylase inhibitors have been studied but no dose has been proven effective. Typically, 1,500-6,000 milligrams amylase inhibitors has been used before meals.
  • For diabetes, 4-6 grams has been used for up to seven days. For weight loss, a dose of 3,000 amylase inhibitor units from Phase 2® (white kidney bean derived amylase inhibitor) has been used daily for 30 days. A dose of 1,500 milligrams Phase 2® has been used twice daily for eight weeks without effect.

Children (under 18 years old)

  • There is no proven safe or effective dose for amylase inhibitors in children.


The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.


  • Avoid in individuals with known allergy or sensitivity to amylase inhibitors or sources of amylase inhibitors, such as wheat or legumes.

Side Effects and Warnings

  • Amylase inhibitors may lower blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood glucose levels may need to be monitored by a qualified healthcare professional and medication adjustments may be necessary.
  • Amylase inhibitors should be used with caution in individuals with gastrointestinal disorders, kidney disorders, or liver problems. When used in combination with other weight loss agents, amylase inhibitors may have additive effects.

Pregnancy and Breastfeeding

  • Amylase inhibitors are not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence.


Interactions with Drugs

  • Amylase inhibitors may lower blood sugar levels. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or injection should be monitored closely by a qualified healthcare provider. Medication adjustments may be necessary.
  • When taken with other weight loss agents, amylase inhibitors may have additive effects.

Interactions with Herbs and Dietary Supplements

  • Amylase inhibitors may lower blood sugar levels. Caution is advised when using herbs or supplements that may also lower blood sugar. Blood glucose levels may require monitoring, and doses may need to be adjusted.
  • When taken with other weight loss agents, including Garcinia cambogia, inulin, and rosmarinic acid, amylase inhibitors may have additive effects. Amylase inhibitors may also interact with guar.

  • This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

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  2. Bo-Linn GW, Santa Ana CA, Morawski SG, et al. Starch blockers--their effect on calorie absorption from a high-starch meal. N.Engl.J Med. 12-2-1982;307(23):1413-1416.
  3. Boivin M, Flourie B, Rizza RA, et al. Gastrointestinal and metabolic effects of amylase inhibition in diabetics. Gastroenterology 1988;94(2):387-394.
  4. Boivin M, Zinsmeister AR, Go VL, et al. Effect of a purified amylase inhibitor on carbohydrate metabolism after a mixed meal in healthy humans. Mayo Clin.Proc. 1987;62(4):249-255.
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  6. Celleno L, Tolaini MV, D'Amore A, et al. A Dietary supplement containing standardized Phaseolus vulgaris extract influences body composition of overweight men and women. Int.J Med.Sci. 2007;4(1):45-52.
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  9. Choudhury A, Maeda K, Murayama R, et al. Character of a wheat amylase inhibitor preparation and effects on fasting human pancreaticobiliary secretions and hormones. Gastroenterology 1996;111(5):1313-1320.
  10. Lankisch M, Layer P, Rizza RA, et al. Acute postprandial gastrointestinal and metabolic effects of wheat amylase inhibitor (WAI) in normal, obese, and diabetic humans. Pancreas 1998;17(2):176-181.
  11. Layer P, Zinsmeister AR, DiMagno EP. Effects of decreasing intraluminal amylase activity on starch digestion and postprandial gastrointestinal function in humans. Gastroenterology 1986;91(1):41-48.
  12. Liener IE, Donatucci DA, Tarcza JC. Starch blockers: a potential source of trypsin inhibitors and lectins. Am.J Clin.Nutr. 1984;39(2):196-200.
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  14. Thom E. A randomized, double-blind, placebo-controlled trial of a new weight-reducing agent of natural origin. J Int.Med.Res. 2000;28(5):229-233.
  15. 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.

Copyright © 2011 Natural Standard (www.naturalstandard.com)

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.

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