Glucomannan. This substance is created from extracts of the konjac plant. It works like dietary fiber supplements that blocks fat from being absorbed in the body. ketozol Earlier studies about glucomannan suggested that it may be helpful for reducing weight, however, there are evidences that show that it is ineffective, too. Evidence is insufficient to prove that glucomannan is efficient for weight management. There are hazards in taking it in tablet form as well. It could cause choking or blockage in the throat, the esophagus and the intestines. It is a safer option to take glucomannan in capsule or powder form. If you're taking other medications, your body might have difficulty in absorbing them if you take glucomannan. You therefore should take your medications 1 hour before taking glucomannan or 4 hours after taking glucomannan.