NOW Glucomannan 575 mg review
The cheapest option here with the most honest safety label — and pooled trial data saying its weight effect rounds to zero
Reviewed August 26, 2026 · Visit nowfoods.com
What this is: a dietary supplement — not an FDA-approved medicine. It has not been evaluated by the FDA for safety, efficacy or quality, and nothing in this review is medical advice or an endorsement. If you are considering stopping or replacing prescribed medication with any product on this page, talk to your clinician first.
Overview
What NOW Glucomannan 575 mg is
Glucomannan is konjac-root soluble fiber — the original 'fills your stomach before dinner' supplement — and NOW's version costs $27 for two months, less than a single week of everything else in this registry. The evidence treatment is exactly what its modest price suggests: randomized trials exist in quantity, meta-analysed repeatedly, and the pooled verdict on body weight is a statistically insignificant 0.22 kg. What remains defensible is conventional fiber utility — satiety as an adjunct to an actual diet plan, cholesterol within normal range, regularity — which is precisely what NOW claims. Its label also carries the most candid safety language in this registry: an explicit choking and esophageal-obstruction warning regulators require for konjac products, printed where you cannot miss it.
Active ingredients
| Ingredient | Published dose |
|---|---|
| Glucomannan (Amorphophallus konjac root fiber) | 575 mg per capsule; 1,725 mg per 3-capsule serving (2 g dietary fiber) |
Best for
Budget-conscious buyers who want pre-meal satiety fiber and will read 'not statistically significant' for what it means.
Limitations
This is the floor of the category: legitimate, certified, honestly labelled, and supported by trial data saying it barely moves weight. As a fiber supplement it's fine; as a GLP-1 anything, it was never claiming to be.
Evidence rating
Peer-reviewed RCTs
Randomized, controlled human trials exist for this ingredient. Read the notes — trial design and sample size matter.
Claims vs evidence
What the brand says, and what we could verify
The company's mechanism claim is quoted or closely paraphrased from its own site. Of 3 cited studies, we could independently confirm 3 in indexed literature.
The claim
Satiety promotion ('feeling of fullness') positioned as 'a convenient addition to a weight management plan that includes a healthy diet and exercise program', alongside supports-healthy-cholesterol and regularity structure/function claims. No GLP-1 claims.
The evidence
Ingredient-level RCT literature is deep and honestly unimpressive for weight: Onakpoya 2014 (J Am Coll Nutr) pooled glucomannan RCTs and found a nonsignificant −0.22 kg versus placebo; Zhang 2023 (Nutrients) meta-analysed glucomannan in type 2 diabetes; Bessell 2021 (Int J Obes) placed it among isolated-compound supplements with minimal pooled effect. Dosing here (up to 3.45 g/day) matches the protocol used across trials, so unlike some entries in this registry, the product delivers what was actually studied — the studies just didn't show much.
| Cited study | Reported finding | Independently verified |
|---|---|---|
| Onakpoya et al. 2014, J Am Coll Nutr (SR/MA of glucomannan RCTs, PMID 24533610) | Pooled body-weight difference −0.22 kg (95% CI −0.62 to 0.19) — not statistically significant | Confirmed on PubMed |
| Zhang et al. 2023, Nutrients (MA in T2D, PMID 36771306) | Glycemic-parameter meta-analysis of glucomannan in type 2 diabetes | Confirmed on PubMed |
| Bessell et al. 2021, Int J Obes (PMID 33976376) | Isolated-compound supplement MA placing glucomannan among minimal-effect interventions | Confirmed on PubMed |
Facts
Regulation, testing, dosing and price
Every figure is published by the brand. Where something is not disclosed, we say so rather than estimating.
- Regulatory status
- Structure-function asterisk claims throughout. Notably, NOW's own shipping policy requires adult signature for New York orders of products carrying weight-loss claims — regulatory handling disclosure, not FDA action. No warning-letter match in recent exports.
- Third-party testing
- Intertek GMP Supplement Certification badge on the product page
- Halal and Kosher certified
- Non-GMO, vegan, keto-friendly claims
- How it's taken
- Three capsules once or twice daily with at least 8 oz of water, 30–45 minutes before a meal.
- Safety disclosures
- Explicit choking caution printed on the listing: without enough liquid the product may swell in the throat causing blockage or choking; avoid with esophageal narrowing or swallowing difficulty. Adults only; physician consult if pregnant, nursing or medicated.
- Manufacturer
- NOW Foods / NOW Health Group
- Subscription
- Not disclosed on the brand's site
- Guarantee
- Unopened items returnable within 30 days for full refund (return shipping paid by customer)
- Price as published
- 180 capsules (60 servings, ~1 month at max dose)$26.99
- Free shipping over $50; no subscription programme
Assessment
Pros and cons
Editorial judgment applied to the published facts above.
Pros
- One-tenth to one-twentieth the monthly cost of everything else reviewed
- Doses match the protocols used in the actual trials — nothing underdosed or proprietary
- Exemplary konjac safety labelling, including the choking hazard most brands bury
- Third-party Intertek GMP certification
Cons
- Pooled randomized-trial evidence for weight loss is effectively null (−0.22 kg NS)
- Three capsules plus 8 oz of water before meals, twice a day, is a demanding ritual
- Choking risk is real for anyone with swallowing difficulties
- Return policy covers unopened bottles only
Alternatives
If NOW Glucomannan 575 mg isn't what you're after
Metamucil
The most honest marketer in the room — it targets people already on GLP-1s instead of pretending to be one
Peer-reviewed evidenceSupergut GLP-1 Daily Support
The boldest GLP-1 branding in the category sits on top of the thinnest verifiable evidence
Vendor-reported onlyNOW Glucomannan 575 mg: frequently asked questions
Does glucomannan work for weight loss?
Why include it on a GLP-1 site at all?
What's the main safety concern?
Sources
Verified August 26, 2026. Supplement formulations and prices change frequently — confirm current details with the brand.
Medical disclaimer
This review is editorial research about a commercial service. It is not medical advice, and it is not a recommendation to start, stop or change any treatment. GLP-1 medications are prescription drugs with real contraindications and side effects. Decisions about whether they are appropriate for you belong with a qualified clinician who knows your medical history. Prices and terms in this category change frequently — we publish the date each review was verified and link every source, but you should confirm current details with the provider before purchasing.