{"ok":true,"entry":{"slug":"glucomannan","kind":"supplement","name":"glucomannan","aliases":["konjac fiber","Amorphophallus konjac"],"brands_sg":["NOW Foods","Nutricost","Absolute Nutrition","Nature's Way","Best Naturals"],"class":"soluble fiber","tags":["gut","general"],"use_for":"konjac fibre that swells in water · little weight effect","use_after":"trials dosed 1–1.33 g before each meal","use_duration":null,"take_with":"water · tablet forms have blocked the esophagus","pros":["absorbs up to 50 times its weight in water","fda counts glucomannan toward dietary fibre","short-term side effects reported were minor"],"cons":["2015 review of 6 trials: no significant weight effect","tablet forms linked to 7 esophageal obstructions","belching, bloating, flatulence and diarrhea reported"],"dose_note":"trials used roughly 1.24 to 3.99 g a day, commonly 1 to 1.33 g before each meal, for up to 12 weeks; a 2015 systematic review of six trials in 293 people and a 2014 meta-analysis of eight trials in 301 people both found no significant effect on body weight, while an older meta-analysis of 14 studies at 1.2 to 15.1 g a day found a 0.79 kg mean difference; ods reports significant safety concerns for tablet forms but few for other forms up to 15.1 g a day for several weeks; fda counts glucomannan toward the dietary fibre declaration on supplement facts labels, but no rda, ul, fda daily value or hsa singapore daily limit exists for glucomannan itself","dosage":{"ul":null,"unit":"g","fda_dv":null,"rda_ai":null,"ul_status":"none_established","population":"general adult","hsa_max_daily":null},"ul_status":"none_established","sg_class":null,"cautions":["tablet forms were linked to seven cases of esophageal obstruction","little is known about long-term safety","reported to lower blood glucose — diabetes medicine users should ask first","not listed in hsa annex a or b — that is not a safety finding"],"clashes":[{"src":["ods_wl_interactions_glucomannan"],"note":"might decrease the absorption of many drugs taken by mouth","with":"oral medicines generally"},{"src":["ods_wl_interactions_glucomannan"],"note":"reported to lower blood glucose, so it could interact","with":"diabetes medications"}],"sources":[{"id":"ods_wl_gluco_mech","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — Glucomannan section, source and mechanism","quote":"Glucomannan is a soluble dietary fiber derived from konjac root (Amorphophallus konjac) that can absorb up to 50 times its weight in water … proposed to increase feelings of satiety and fullness and prolong gastric emptying","accessed":"2026-08-27"},{"id":"ods_wl_gluco_table","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — Table 1 summary row for glucomannan","quote":"Glucomannan … Research findings: Little to no effect on body weight … Significant safety concerns reported for tablet forms, which might cause esophageal obstructions, but few safety concerns with up to 15.1 g/day of other forms for several weeks","accessed":"2026-08-27"},{"id":"ods_wl_gluco_sr","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — 2015 systematic review","quote":"The authors of a 2015 systematic review of six randomized controlled trials with a total of 293 participants concluded that 1.24 to 3.99 g/day glucomannan for up to 12 weeks does not have a significant effect on body weight","accessed":"2026-08-27"},{"id":"ods_wl_gluco_dose","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — how the trials dosed it","quote":"consumed 3 g/day glucomannan (1 g before each meal) or placebo for 8 weeks … supplementation with glucomannan (1.33 g before each meal for a total of 3.99 g/day)","accessed":"2026-08-27"},{"id":"ods_wl_gluco_safety","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — long-term safety, side effects and the obstruction reports","quote":"Little is known about the long-term safety of glucomannan … minor adverse effects, including belching, bloating, loose stools, flatulence, diarrhea, constipation, and abdominal discomfort … seven cases of esophageal obstruction in 1984–1985 in Australia","accessed":"2026-08-27"},{"id":"ods_wl_interactions_glucomannan","url":"https://web.archive.org/web/20260826105104/https://ods.od.nih.gov/factsheets/WeightLoss-HealthProfessional/","label":"NIH ODS — Dietary Supplements for Weight Loss (Health Professional), updated 18 May 2022; read via the archive.org capture of 26 Aug 2026 because ods.od.nih.gov returns HTTP 403 to direct fetches — interactions section","quote":"glucomannan and guar gum might decrease the absorption of many drugs that are taken orally … Glucomannan has been reported to lower blood glucose levels and, therefore, could interact with diabetes medications","accessed":"2026-08-27"},{"id":"fda_fiber_glucomannan","url":"https://www.fda.gov/food/nutrition-food-labeling-and-critical-foods/questions-and-answers-dietary-fiber","label":"US FDA — Questions and Answers on Dietary Fiber (page current as of 25 July 2024), actions taken on dietary fiber","quote":"January 2020: FDA added “glucomannan” to the existing list of isolated or synthetic non-digestible carbohydrates that FDA intends to propose to be added to the definition of dietary fiber.","accessed":"2026-08-27"},{"id":"hsa_prohibited","url":"https://file.go.gov.sg/hsa-chp-prohibited-restricted-ing-guidelines.pdf","label":"HSA Singapore — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev. No. 001 (October 2025) — Annex A (118 rows) and Annex B (4 rows): glucomannan / konjac / Amorphophallus konjac is NOT LISTED in either; Annex A runs 51. Ginkgo biloba then 52. Gluta usitata, with no glucomannan between them","quote":"The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list.","accessed":"2026-08-27"},{"id":"hsa_hs_guidelines","url":"https://file.go.gov.sg/hsa-hs-guidelines.pdf","label":"HSA Singapore — Health Supplements Guidelines GL-CHPB-3-001 (January 2026), clause 4.8 with Tables 4–5, which list vitamins and minerals only — no botanical or fibre rows","quote":"4.8 HS for use by the general adult population should not contain vitamins and minerals exceeding the stipulated limits stated in Tables 4 and 5.","accessed":"2026-08-27"},{"id":"iherb_sg","url":"https://sg.iherb.com/c/glucomannan","label":"iHerb Singapore — Glucomannan category page, default listing order, 27 Aug 2026","quote":"1 - 15 of 15 results: NOW Foods, Glucomannan, 575 mg; Nutricost, Glucomannan Konjac Root Extract; NOW Foods, Glucomannan, Pure Powder; Absolute Nutrition, Absolutely Full; Nature's Way, Glucomannan from Konjac Root; Best Naturals, Konjac Root","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:21.812539+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}