Health Guide


What is it?

Glucomannan is a dietary supplement used for diabetes, hypoglycemia (low blood sugar), high blood pressure, high cholesterol (blood fats), constipation (difficulty having a bowel movement), and weight loss.

Other names for Glucomannan include: Glucomanna, Konjac, Konjac Fiber, Konjac Glucomanna, Konjac Glucomannan, and Manna.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much Glucomannan you should take. The amount depends on the strength of the medicine and the reason you are taking Glucomannan. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.

Drug and Food Interactions:

Do not take Glucomannan without talking to your doctor first if you are taking:

  • Medicine used to lower blood sugar (examples: insulin, glyburide (Diabeta(R), Micronase(R)), metformin (Glucophage(R)), glipizide (Glucotrol(R)))


  • Before taking Glucomannan, tell your doctor if you are pregnant or breastfeeding
  • Glucomannan tablets have gotten stuck in the esophagus (throat) of some people (7)

Side Effects:

Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

  • Breathing problems or tightness in your throat or chest
  • Chest pain
  • Skin hives, rash, or itchy or swollen skin

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

  • Upset stomach, diarrhea (loose bowel movements), throwing up, and gas (8,9)


1. Passaretti S, Franzoni M, Comin U et al. Action of glucomannans on complaints in patients affected with chronic constipation: a multicentric clinical evaluation. Ital J Gastroenterol 1991; 23(7):421-425.

2. Vuksan V, Sievenpiper J, Owen R et al: Beneficial effects of viscous dietary fiber from Konjac-mannan in subjects with the insulin resistance syndrome. Diabetes Care 2000; 23:9-14.

3. Walsh DE, Yaghoubian V & Behforooz A: Effect of glucomannan on obese patients: a clinical study. Int J Obes 1984; 8(4):289-293.

4. Doi K, Matsuura M, Kawara A et al: Treatment of diabetes with glucomannan (Konjac mannan). Lancet 1979; 1(8123):987-988.

5. Shima K, Tanaka A, Ikegami H et al: Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man. Horm Metabol Res 1983; 15(1):1-3.

6. Doi K: Effect of konjac fibre (glucomannan) on glucose and lipids. Eur J Clin Nutr 1995; 49(3):S190-S197.

7. Henry D, Mitchell A & Aylward J: Glucomannan and risk of esophageal obstruction. BMJ 1986; 292(6520):591-592.

8. Kneepkens F, Fernandes J & Vonk R: Dumping syndrome in children. Acta Pediatr Scand 1988; 77(12):279-286.

9. Vuksan V, Jenkins D, Spadafora P et al: Konjac-glucomannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. Diabetes Care 1999; 22:913-919.

Last Updated: 7/4/2018
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