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Fiber (psyllium, inulin, glucomannan) supplements, compared

15 products we’ve reviewed list fiber (psyllium, inulin, glucomannan) as a key ingredient. Here’s what it does, what the research uses — and how much each product actually contains.

What it is

Soluble fibers absorb water, add bulk and — in the case of prebiotics like inulin — feed gut bacteria.

What the research uses

The recommendation for adults is 21–38 g of fiber a day from all sources — most Americans get about 16 g. Increase slowly and drink plenty of water to avoid bloating.

Educational information, not medical advice. Talk to a healthcare professional before starting a supplement, especially if you are pregnant, nursing or take medication.

Every product, dose by dose

ProductFiber (psyllium, inulin, glucomannan) per servingFormScore
4-in-1 Psyllium Fiber Powder, Sugar-Free
Metamucil4-in-1 Psyllium Fiber Powder, Sugar-Free		3 g dietary fiber (2 g soluble) per rounded teaspoonPsyllium husk fiberPowder8.3
Black Edition
HuelBlack Edition
Third-party tested
11 gDietary fiberPowder8.1
Digestive Daily Probiotic Capsules
CulturelleDigestive Daily Probiotic Capsules
cGMP facility
200 mgInulin (chicory root extract)Capsule8.0
Organic Protein Plant-Based Protein Powder
OrgainOrganic Protein Plant-Based Protein Powder
USDA OrganicKosher
7 g total dietary fiberOrganic agave inulin and acacia fiberPowder7.5
All-In-One Nutrition Shake
Ka'ChavaAll-In-One Nutrition Shake
Third-party testedcGMP facility
6 g fiberFiber & Probiotics Blend (flax, acacia gum, chia, soluble corn fiber, chicory root, L. rhamnosus Lrha51, L. acidophilus UALa-01)Powder7.2
Organic Nutrition Shake
OrgainOrganic Nutrition Shake
USDA OrganicKosher
Not disclosedOrgain Organic Fruit & Vegetable Blend (apple fiber, acai, beet, kale, raspberry, spinach, tomato, banana, blueberry, carrot)Ready to drink7.1
Glucomannan 575 mg Veg Capsules
NOW FoodsGlucomannan 575 mg Veg Capsules
cGMP facilityKosherHalal
1,725 mg per serving (575 mg per capsule)Glucomannan (from konjac root, Amorphophallus konjac)Capsule6.9
Super Greens The Original
Amazing GrassSuper Greens The Original
KoshercGMP facility
620 mgFiber Blend (organic flax seed, apple pectin)Powder6.8
Superfoods Greens Gummies
GrünsSuperfoods Greens Gummies
Third-party testedcGMP facility
6 gDietary fiber (tapioca fiber, organic inulin)Gummy6.8
20g Plant Protein Shake
OWYN20g Plant Protein Shake
Non-GMO Project VerifiedKosher
3 g fiberSoluble fiberReady to drink6.7
Greens & Superfoods
Bloom NutritionGreens & Superfoods
Third-party testedcGMP facility
1.606 gFiber Blend (chicory root fructo-oligosaccharides, organic flaxseed, apple fruit powder)648 mgPre and Probiotic Blend (blue agave inulin, B. bifidum, L. rhamnosus, L. acidophilus)Powder6.1
Super Greens
Live it UpSuper Greens
Third-party testedcGMP facility
3 gDietary fiberPowder5.9
Mushroom Coffee
RYZEMushroom Coffee
USDA Organic
Not disclosedOrganic prebiotic blend (acacia, inulin, tapioca fiber)Powder5.7
Field of Greens
BrickHouse NutritionField of Greens
USDA OrganicThird-party testedcGMP facility
Not disclosedOrganic Antioxidant Powder Blend (blueberry, cranberry, raspberry, strawberry, beet root) with organic inulin2 gDietary fiberPowder5.4
GLP-1 Probiotic
PendulumGLP-1 Probiotic		211 mgChicory inulinCapsule4.9

Amounts are per serving as printed on each label. “Not disclosed” usually means the ingredient sits inside a proprietary blend.

Questions people ask

How much fiber (psyllium, inulin, glucomannan) do studies use?
The recommendation for adults is 21–38 g of fiber a day from all sources — most Americans get about 16 g. Increase slowly and drink plenty of water to avoid bloating.
Which fiber (psyllium, inulin, glucomannan) supplement scores highest?
In our reviews, Metamucil 4-in-1 Psyllium Fiber Powder, Sugar-Free scores highest at 8.3/10, followed by Huel Black Edition (8.1) and Culturelle Digestive Daily Probiotic Capsules (8.0). Scores weigh efficacy, quality, value, experience and transparency — not just the dose.
How much fiber (psyllium, inulin, glucomannan) is in these products?
It varies by product and serving size — for example Metamucil 4-in-1 Psyllium Fiber Powder, Sugar-Free (3 g dietary fiber (2 g soluble) per rounded teaspoon), Huel Black Edition (11 g), Culturelle Digestive Daily Probiotic Capsules (200 mg). The table above lists the amount per serving for every product we've reviewed.

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