Top 8 Best Glucomannan Supplements for Weight Loss (2026)
01 · Best Overall✓ Label verified · Supplement Facts read Sep 7, 2026Best Overall: NOW Foods Glucomannan 575 mg
1.725 g of glucomannan per three vegetarian capsules, taken once or twice a day before a meal, with the water rule, the timing and the choking caution all printed on the bottle.
$16-18~$0.28 per 3-capsule serving (1.725 g)
Why it wins: all five scores, pros & cons, full label
- 1.725 g of declared glucomannan per serving
- Water, timing and choking caution printed
- Vegetarian capsule, GMP-certified brand
- Dose splits before two meals
- Three capsules per serving
- No third-party testing statement on the label
- Four excipients
- Per serving
- 1.725 g glucomannan (from konjac root)
- Cost per dose
- ~$0.28 per serving
- Directions
- 3 capsules 1 to 2 times daily with at least 8 oz. of water, 30-45 minutes before a meal
- Form
- Veg capsule (hypromellose)
- Serving
- 3 capsules
- Count
- 180 capsules (60 servings)
- Other ingredients
- Hypromellose, hydroxypropyl cellulose, silicon dioxide, microcrystalline cellulose, stearic acid (vegetable source)
- Seals
- GMP Quality Assured, Non-GMO, vegetarian/vegan
Our take — If you want to try glucomannan the way it was studied, this is the bottle that tells you how. Take three capsules with a full glass of water half an hour before your biggest meal, never dry and never lying down, and treat it as a fullness aid inside a calorie deficit rather than a fat burner.
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08Who Wins Which Aspect
Sorted by overall SAC Product Score™ — the official ranking.
| # | Pick | Score | Dose vs the Trials30% | Label Directions & Safety20% | Testing & Manufacturing20% | Formulation & Form15% | Value15% | Cost Per Dose | Buy |
|---|---|---|---|---|---|---|---|---|---|
| 01 | | 8.8 | 9.21 | 9.23 | 8.62 | 8.2 | 8.4 | ~$0.28 / serving | Check price |
| 1.725 g of declared glucomannan per servingThree capsules per serving | |||||||||
| 02 | | 8.7 | 8.63 | 8.4 | 8.62 | 8.62 | 9.81 | ~$0.14 / serving | Check price |
| No other ingredientsMust be measured and drunk before it gels | |||||||||
| 03 | | 8.6 | 8.82 | 9.42 | 7.8 | 8.81 | 7.8 | ~$0.38 / serving | Check price |
| 1.995 g of declared glucomannan per servingContains sulfites | |||||||||
| 04 | | 8.5 | 7.8 | 8.6 | 8.62 | 8.43 | 9.62 | ~$0.15 / serving | Check price |
| Cheapest capsule per gramSold as a two-bottle pack | |||||||||
| 05 | | 8.3 | 8.0 | 9.61 | 8.0 | 7.4 | 8.63 | ~$0.38 / serving | Check price |
| Most complete directions and safety noticeGelatin capsule | |||||||||
| 06 | | 7.7 | 8.0 | 6.0 | 8.81 | 7.2 | 8.63 | ~$0.28 / serving | Check price |
| Third-party testing printed on the labelNo choking warning on the bottle | |||||||||
| 07 | | 7.5 | 7.0 | 6.0 | 8.43 | 8.62 | 8.2 | ~$0.33 / serving | Check price |
| Veg capsule with one fillerPanel declares extract, not glucomannan | |||||||||
| 08 | | 6.7 | 8.63 | 9.0 | 5.0 | 5.0 | 4.0 | ~$0.55 / serving | Check price |
| Before-each-meal schedule printedHighest price per gram on the list | |||||||||
The Other 7, Ranked
- 02
Best Budget Pure Powder: NOW Foods Glucomannan Pure Powder 8 oz
8.7SAC Score™Nothing but glucomannan: 2 g per half teaspoon, about 114 servings a jar, at half the cost per gram of any capsule here. It has to be measured, stirred and drunk before it gels.
StrongestValue9.81WeakestLabel Directions & Safety8.4- Per serving
- 2 g glucomannan (from konjac root)
- Cost per dose
- ~$0.14 per serving
- Directions
- 1/2 level teaspoon 1 to 2 times daily with at least 8 oz. of water, 30-45 minutes before a meal
All five scores, pros & cons, full label
What We Like- No other ingredients
- Lowest cost per gram on the list
- Right directions and caution printed
- About 114 servings a jar
What You Live With- Must be measured and drunk before it gels
- Approximate half-teaspoon dose
- Not portable
- Form
- Powder
- Serving
- 1/2 level teaspoon (approx. 2 g)
- Count
- 8 oz (227 g), about 114 servings
- Other ingredients
- None
- Seals
- GMP Quality Assured, Non-GMO, vegetarian/vegan, kosher, halal
Our take — If you are disciplined about stirring half a teaspoon into a full glass of water and drinking it straight away, NOW's powder gives you the studied fiber for pennies. If that sounds like a chore you will skip, buy the capsule; the dose you take is the one that counts.
- 03
Best Premium Clean Label: Nature's Way Glucomannan 1,995 mg
8.6SAC Score™1.995 g of glucomannan per three vegan capsules with only magnesium stearate added, Non-GMO Project Verified, and the fullest choking warning on the list; the smallest bottle and the highest price per gram among the plain capsules.
StrongestLabel Directions & Safety9.42WeakestTesting & Manufacturing7.8- Per serving
- 1.995 g glucomannan (from Amorphophallus konjac root)
- Cost per dose
- ~$0.38 per serving
- Directions
- 3 capsules with at least 8 oz. (full glass) of water about 20 minutes before mealtime
All five scores, pros & cons, full label
What We Like- 1.995 g of declared glucomannan per serving
- Only one excipient, vegan capsule
- Non-GMO Project Verified
- Most complete choking warning
What You Live With- Contains sulfites
- No testing statement on the panel
- Only 33 servings a bottle
- Form
- Vegan capsule (hypromellose)
- Serving
- 3 capsules
- Count
- 100 capsules (33 servings)
- Other ingredients
- Plant-derived capsule (hypromellose), magnesium stearate; contains sulfites
- Seals
- Non-GMO Project Verified, vegan, gluten-free, dairy-free
Our take — Nature's Way gets the dose, the directions and the warning right and adds almost nothing to the fiber. You pay for that in bottle size. If the ingredient list is your first filter, buy it; if value is, NOW or Best Naturals gives you the same grams for less.
- 04
Best Bulk Buy: Best Naturals Konjac Root Glucomannan 2,000 mg (2-Pack)
8.5SAC Score™Two bottles of 180 vegetarian capsules, 2,000 mg of konjac root glucomannan per three, third-party lab tested per the label, with the water rule and choking caution printed; a once-a-day direction and a sloppy listing graphic hold it back.
StrongestValue9.62WeakestDose vs the Trials7.8- Per serving
- 2,000 mg konjac root (glucomannan)
- Cost per dose
- ~$0.15 per serving
- Directions
- 3 capsules daily with at least 8 oz of water, 30-45 minutes before a meal
All five scores, pros & cons, full label
What We Like- Cheapest capsule per gram
- Timing, water and choking caution printed
- Vegetarian capsule
- Third-party lab testing claimed on the label
What You Live With- Sold as a two-bottle pack
- Listing graphic contradicts the panel
- Once-daily direction only
- Form
- Vegetarian capsule (vegetable cellulose)
- Serving
- 3 capsules
- Count
- 2 bottles x 180 capsules (60 servings each)
- Other ingredients
- Capsule (vegetable cellulose), silicon dioxide, magnesium stearate (vegetable source), microcrystalline cellulose
- Seals
- 3rd Party Lab Tested, GMP, made in USA
Our take — If you already know glucomannan agrees with you and want months of it cheaply, this two-pack is the sensible purchase. Trust the Supplement Facts panel over the listing art, take it with a full glass of water before a meal, and split the three capsules across two meals if one large dose sits heavily.
- 05
Best Label Directions: Carlyle Glucomannan 2,400 mg
8.3SAC Score™2,400 mg of glucomannan per four quick-release capsules with the most useful directions on the list: water, timing, a choking notice, not before sleep and a gap from medications. Gelatin capsule, one large daily serving.
StrongestLabel Directions & Safety9.61WeakestFormulation & Form7.4- Per serving
- 2,400 mg glucomannan (from konjac root)
- Cost per dose
- ~$0.38 per serving
- Directions
- 4 capsules daily with at least 8 ounces of water or other fluid, 30 to 60 minutes before or with a meal
All five scores, pros & cons, full label
What We Like- Most complete directions and safety notice
- Medication-spacing guidance printed
- 2,400 mg of declared glucomannan per serving
- Low cost per gram for a capsule
What You Live With- Gelatin capsule
- Four capsules per serving
- Testing is the brand's own statement
- Form
- Quick-release capsule (gelatin)
- Serving
- 4 capsules
- Count
- 200 capsules (50 servings)
- Other ingredients
- Gelatin capsule, rice powder, vegetable magnesium stearate
- Seals
- Non-GMO, GMP, packaged and lab tested in the USA
Our take — Carlyle earns its place on directions. If you are on medication, or simply want a bottle that tells you everything, it is the careful choice. Vegetarians and anyone wanting an independent testing claim should look two places up the list.
- 06
Best Third-Party Tested: Nutricost Glucomannan 1,800 mg
7.7SAC Score™1,800 mg of glucomannan per three capsules with third-party testing and a GMP-compliant facility printed on the bottle; the directions give water but no meal timing and no choking warning, and the capsule is gelatin.
StrongestTesting & Manufacturing8.81WeakestLabel Directions & Safety6.0- Per serving
- 1,800 mg glucomannan (from konjac root extract)
- Cost per dose
- ~$0.28 per serving
- Directions
- 3 capsules daily with 8-12 oz of water
All five scores, pros & cons, full label
What We Like- Third-party testing printed on the label
- GMP-compliant facility, Non-GMO, gluten-free
- Fair price for 60 servings
- 1,800 mg of declared glucomannan
What You Live With- No choking warning on the bottle
- No pre-meal timing in the directions
- Gelatin capsule, although the listing says vegan
- Form
- Capsule (gelatin)
- Serving
- 3 capsules
- Count
- 180 capsules (60 servings)
- Other ingredients
- Gelatin capsule, rice extract blend (rice extract, rice hulls, gum arabic, sunflower oil), calcium laurate
- Seals
- Third Party Tested, GMP Compliant Facility, Non-GMO, gluten-free
Our take — Nutricost's glucomannan is a sound product let down by its instructions. If you know to take it with a full glass of water before a meal and never dry, it is a fair buy. If you want the bottle to tell you that, NOW and Carlyle do.
- 07
Best Two-Ingredient Capsule: BulkSupplements Glucomannan Capsules 2,000 mg
7.5SAC Score™A vegetarian capsule with only rice flour added, third-party tested per the listing; the panel declares 2,000 mg of konjac root extract rather than a glucomannan amount, and the listing shows no timing or choking warning.
StrongestFormulation & Form8.62WeakestLabel Directions & Safety6.0- Per serving
- 2,000 mg konjac root extract (Amorphophallus konjac root)
- Cost per dose
- ~$0.33 per serving
- Glucomannan content
- Not stated on the panel
All five scores, pros & cons, full label
What We Like- Veg capsule with one filler
- Third-party tested and cGMP per the listing
- 240 capsules, 60 servings
- Allergens: none
What You Live With- Panel declares extract, not glucomannan
- No timing or choking warning shown in the listing
- Four capsules per serving
- Form
- Veg capsule (hypromellose)
- Serving
- 4 capsules
- Count
- 240 capsules (60 servings)
- Directions
- 4 capsules with 8-12 oz of water (listing gallery)
- Other ingredients
- Rice flour, hypromellose capsules
- Seals
- Gluten-free, soy-free, dairy-free; third-party tested and cGMP (listing)
Our take — BulkSupplements makes a tidy two-ingredient capsule and backs it with a testing badge. For glucomannan, though, the dose of fiber and the way you take it are the product, and this listing is vague on both. Choose it for the ingredient line; choose NOW for the label.
- 08
Best-Known Brand: Lipozene Maximum Strength 1,500 mg
6.7SAC Score™The famous blue diet pill is konjac glucomannan: 1,500 mg per two capsules, up to three times a day before meals, with the choking warning printed. It costs more than twice as much per gram as NOW, in a gelatin capsule with titanium dioxide and FD&C Blue #1, and prints no testing statement.
StrongestLabel Directions & Safety9.0WeakestValue4.0- Per serving
- 1,500 mg proprietary blend: Amorphophallus konjac (from konjac root)
- Cost per dose
- ~$0.55 per serving
- Directions
- 2 capsules 30 minutes before meals, up to three times per day, with at least 8 oz. of water
All five scores, pros & cons, full label
What We Like- Before-each-meal schedule printed
- Complete choking warning
- Two capsules per serving
- Widely available
What You Live With- Highest price per gram on the list
- Artificial color and titanium dioxide
- No testing statement
- 'Clinically proven' claim not backed by the pooled trials
- Form
- Capsule (gelatin)
- Serving
- 2 capsules
- Count
- 120 capsules (60 servings)
- Other ingredients
- Gelatin, water, titanium dioxide, stearic acid, cellulose, magnesium silicate, artificial color (FD&C Blue #1)
- Seals
- None printed
Our take — Lipozene is not a scam ingredient; it is ordinary glucomannan with good directions. It is an expensive way to buy it, in a capsule with additives the others avoid, behind a claim the independent evidence does not support. Buy NOW and follow Lipozene's schedule.
Glucomannan In Four Short Lessons
Take it with a full glass of water, never dry.
Glucomannan expands to many times its size on contact with fluid, and cases of esophageal obstruction are on record (Henry 1986, Vanderbeek 2007). Six of the eight labels here print a choking warning; buy one of those, swallow the capsules with at least a full glass of water, and do not take it lying down or just before sleep.
Buy grams of glucomannan, before meals.
The trials gave 1 g to 1.33 g in capsules about an hour before each meal. Check that the panel declares glucomannan rather than only konjac root extract, and that a serving lands near 2 g. A label that says three capsules daily without a time leaves out the part that makes the dose work.
Expect fullness, not fat loss.
The best-run trial found no more weight loss than placebo over eight weeks (Keithley 2013), and the 2014 meta-analysis found no significant effect (Onakpoya 2014). A lipid benefit is better supported (Sood 2008). Treat glucomannan as a tool for eating less inside a calorie deficit, and ignore any bottle that promises more.
Walsh 1984 (PMID 6096282); Keithley 2013 (PMID 24490058); Onakpoya 2014 (PMID 24533610); Sood 2008 (PMID 18842808); Henry 1986 (PMID 3004635); Vanderbeek 2007 (PMID 17357389).
Every product here is the same fiber, so the ranking turns on the label. The largest share of the score, 30 percent, asks whether a serving and its directions reproduce the trials: about 1 g to 1.33 g of glucomannan in capsules before meals, 2 to 4 g a day, declared as glucomannan rather than as an extract weight. The next 20 percent is specific to this fiber: glucomannan swells, obstruction cases are documented, and a label that prints the water, the timing and the choking warning is safer than one that does not. Testing and manufacturing follow at 20 percent, read from the label or the listing. Formulation covers the capsule and excipients, and value closes the score as a tie-breaker. Every number we cite was read from the product's own Supplement Facts panel.
Dose vs the Trials · 30%
The trials gave glucomannan in capsules before meals: 1 g three times a day in Walsh 1984, 1.33 g three times a day in Keithley 2013, and 2 to 4 g a day across the studies Keithley 2005 reviewed. We scored how closely a label serving and its directions reproduce that pattern, whether the panel declares glucomannan or only konjac root extract, and how easily the serving splits into pre-meal doses.
Label Directions & Safety · 20%
Glucomannan swells on contact with water, and cases of esophageal obstruction are on record (Henry 1986, Vanderbeek 2007). A label that prints a full glass of water, a time before the meal and a choking warning scores highest; a label that prints only a serving size scores lowest.
Testing & Manufacturing · 20%
Third-party testing, GMP certification and lab statements, read from the label or the listing gallery. A printed third-party statement outranks an in-house quality claim; no statement at all scores lowest.
Formulation & Form · 15%
What surrounds the fiber: a vegetarian capsule beats gelatin, two excipients beat five, and artificial colors or titanium dioxide cost points. Pure powder has the cleanest ingredient line but has to be measured and drunk before it gels.
Value · 15%
Cost per gram of fiber at the listed price. A tie-breaker only: a cheap capsule with incomplete directions does not out-rank a properly labelled one.
How Glucomannan Works
- 1
It soaks up water and swells
Glucomannan is strongly hygroscopic: it absorbs fluid and expands to many times its original size, forming a thick gel. That is the whole mechanism, and it is why the water you take with it is part of the dose.
- 2
The gel takes up room and slows the meal
Taken before eating, the gel adds bulk in the stomach. Reviews credit its effects to satiety and to a small loss of energy in the stool (Keithley 2005).
- 3
The lipid effect is the better-supported one
Across 14 randomized trials glucomannan lowered total and LDL cholesterol and fasting glucose, with a small drop in body weight (Sood 2008).
- 4
Weight loss itself is unproven
A 2013 trial found no more weight loss than placebo and no change in hunger or fullness ratings, and a 2014 meta-analysis found no significant effect on weight (Keithley 2013, Onakpoya 2014).
What to Expect From Glucomannan
Fullness, or nothing
Taken with a full glass of water about half an hour before a meal, the fiber gels in the stomach. Some people feel fuller; in the 2013 trial fullness ratings did not differ from placebo.
The gut adjusts
Abdominal discomfort, diarrhea and constipation were the adverse events recorded in the trials. Start with one serving a day and keep the water generous.
Where the trials measured
The positive early trial and the negative 2013 trial both ran eight weeks. One reported a 5.5 lb loss, the other no difference from placebo. Judge it against your own food log, not the label.
A fiber habit with rules
Keep it before meals with a full glass of water, away from bedtime, and leave a gap from medications. Stop if swallowing ever feels difficult.
The bottom line
NOW's capsule is the reference glucomannan.
1.725 g per serving, once or twice a day before a meal, with the water rule and the choking caution printed, in a vegetarian capsule. It is the trial routine written on a bottle.
The powder is the value play, if you respect it.
Pure glucomannan at about fourteen cents a serving. It has to be stirred into a full glass and drunk before it gels, and it must never be taken dry.
The label is a safety feature.
Carlyle and Nature's Way print the fullest warnings; Nutricost prints none. For a fiber that swells, that difference is worth more than a few cents a serving.
Lipozene is glucomannan at a premium.
The same konjac fiber with a good dosing schedule, an artificial dye and a claim the pooled trials do not support, at more than twice the price per gram.
Quick Answers
What is the best glucomannan pick overall?
NOW Foods Glucomannan 575 mg by NOW Foods is our #1 pick (SAC score 8.8/10). If you want to try glucomannan the way it was studied, this is the bottle that tells you how. Take three capsules with a full glass of water half an hour before your biggest meal, never dry and never lying down, and treat it as a fullness aid inside a calorie deficit rather than a fat burner.
What is the best budget option?
NOW Foods Glucomannan Pure Powder 8 oz at $15-17. If you are disciplined about stirring half a teaspoon into a full glass of water and drinking it straight away, NOW's powder gives you the studied fiber for pennies. If that sounds like a chore you will skip, buy the capsule; the dose you take is the one that counts.
How much do these picks cost?
Across our ranked picks, prices run from about $12 to $32 — exact price and cost per serving are listed on every pick card above.
How were these picks ranked?
Every product here is the same fiber, so the ranking turns on the label. The largest share of the score, 30 percent, asks whether a serving and its directions reproduce the trials: about 1 g to 1.33 g of glucomannan in capsules before meals, 2 to 4 g a day, declared as glucomannan rather than as an extract weight. The next 20 percent is specific to this fiber: glucomannan swells, obstruction cases are documented, and a label that prints the water, the timing and the choking warning is safer than one that does not. Testing and manufacturing follow at 20 percent, read from the label or the listing. Formulation covers the capsule and excipients, and value closes the score as a tie-breaker. Every number we cite was read from the product's own Supplement Facts panel.
Every Claim Ranked Above Traces Back To One Of These
8 peer-reviewed sources, each linked to PubMed
- [1] Walsh DE, et al. Int J Obes. 1984;8(4):289-93. PMID 6096282 — Effect of glucomannan on obese patients: a clinical study. In an eight-week double-blind trial in 20 obese subjects, 1 g of glucomannan with 8 oz of water one hour before each of three meals produced a mean weight loss of 5.5 lb and lowered total and LDL cholesterol; no adverse reactions were reported.
- [2] Keithley J, Swanson B. Altern Ther Health Med. 2005;11(6):30-4. PMID 16320857 — Glucomannan and obesity: a critical review. A critical review concluding that at 2 to 4 g per day glucomannan was well tolerated and produced significant weight loss in overweight and obese individuals, probably by promoting satiety and fecal energy loss, while calling for further safety and efficacy trials.
- [3] Sood N, et al. Am J Clin Nutr. 2008;88(4):1167-75. PMID 18842808 — Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis. Pooling 14 randomized trials with 531 participants, glucomannan lowered total cholesterol by 19.3 mg/dL, LDL cholesterol by 16.0 mg/dL, triglycerides by 11.1 mg/dL, fasting glucose by 7.4 mg/dL and body weight by 0.79 kg.
- [4] Keithley JK, et al. J Obes. 2013;2013:610908. PMID 24490058 — Safety and efficacy of glucomannan for weight loss in overweight and moderately obese adults. In 53 overweight and moderately obese adults, 1.33 g of glucomannan with 8 oz of water one hour before each meal for eight weeks was well tolerated but produced no more weight loss than placebo and did not change body composition, hunger or fullness.
- [5] Onakpoya I, et al. J Am Coll Nutr. 2014;33(1):70-8. PMID 24533610 — The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials. A meta-analysis of eight randomized trials found a non-significant difference in weight loss between glucomannan and placebo (mean difference -0.22 kg); adverse events included abdominal discomfort, diarrhea and constipation.
- [6] Zalewski BM, et al. Nutrition. 2015;31(3):437-42.e2. PMID 25701331 — The effect of glucomannan on body weight in overweight or obese children and adults: a systematic review of randomized controlled trials. A systematic review of six randomized trials found some short-term reductions in body weight in individual adult trials but no favorable effect of glucomannan on body mass index in any trial.
- [7] Henry DA, et al. Br Med J (Clin Res Ed). 1986;292(6520):591-2. PMID 3004635 — Glucomannan and risk of oesophageal obstruction. A British Medical Journal report on the risk of oesophageal obstruction with glucomannan, the reason labels now tell users to take it with plenty of water.
- [8] Vanderbeek PB, et al. Clin Toxicol (Phila). 2007;45(1):80-2. PMID 17357389 — Esophageal obstruction from a hygroscopic pharmacobezoar containing glucomannan. A case report of esophageal obstruction from a glucomannan-containing product; the authors note that the fiber is strongly hygroscopic and expands rapidly to many times its original size.
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