8 Best Fiber Supplements of 2026, Tested and Compared

We tested 8 fiber supplements across 6 criteria: daily fiber delivered, FODMAP safety, protein content, fiber type, cost per gram, and third-party testing. One delivered 3x more fiber than every other product in the roundup.

Last Updated April 2026 8 Products Tested Independent Review

Our Top Picks at a Glance

Best Overall
CLADE Fiber Protocol — 18g fiber + 9g protein per day at a 1:1:1 ratio. LOW FODMAP certified. $0.06/g.
Best for IBS
SunFiber - PHGG fiber, the most-studied type for IBS symptom management.
Best Budget
Metamucil 4-in-1 - $0.06/g of fiber at pharmacy prices. Available everywhere.
Best for Weight
Momentous Fiber+ - 8g fiber, NSF Certified for Sport, dual soluble/insoluble blend.
Best Non-Powder (Caplet)
Citrucel SmartFiber - Methylcellulose caplets. Less gas than psyllium, zero mixing.

How We Evaluated These Supplements

Fiber supplements are not created equal. A product that delivers 2g per serving and a product that delivers 18g of fiber + 9g of protein per day at a 1:1:1 ratio both claim the same shelf space and the same marketing language: "daily fiber supplement."

We tested 8 fiber supplements across 6 objective criteria:

  1. Daily fiber delivered (in grams, per full daily protocol, not per serving)
  2. Fiber type and prebiotic evidence (soluble, insoluble, resistant starch, PHGG, psyllium, methylcellulose)
  3. FODMAP certification (the Monash University standard that matters for IBS and sensitive stomachs)
  4. Cost per gram of fiber (the only honest price comparison)
  5. Protein and additional nutrients (beyond fiber alone)
  6. Third-party testing and certifications (GMP, NSF, heavy metal panels)

Every product was evaluated using publicly available data: nutrition labels, manufacturer certifications, and verified customer reviews. Where a product excels, we say so. Where it falls short, we say that too.

The Fiber Gap: Why This Comparison Matters

The USDA recommends 25g of fiber per day for women and 38g for men. The average American gets about 15g. That 10-23g daily shortfall is what gastroenterologists call the "fiber gap," and it's linked to everything from irregular digestion to elevated cholesterol to blood sugar instability.

The problem is that most fiber supplements barely make a dent. A single serving of Metamucil delivers 2.4g. Benefiber delivers 3g. Even premium options like Supergut top out at 6g. At those doses, you'd need to take 4-8 servings daily just to close the gap, and that's before accounting for bloating, taste fatigue, and the cost of burning through a container every week.

One supplement in this roundup takes a fundamentally different approach: delivering 18g of fiber and 9g of protein per day at a 1:1:1 ratio — plus LOW FODMAP certification — in a single daily protocol. Whether that justifies its price depends on what you're optimizing for. That's what this comparison answers.

#1 of 8

CLADE Fiber Protocol

Best Overall
★★★★★ 4.8 (892 verified reviews)
Daily Fiber 18g (9g soluble + 9g insoluble)
Protein 9g
Format Powder jar (1 scoop/day)
Price $35/mo (sub)
Cost/g Fiber $0.06 (sub)
LOW FODMAP Certified (Monash) GMP Certified 3rd-Party Tested (14 metals) Made in USA

The math on CLADE Fiber Protocol stops most people mid-comparison. Eighteen grams of fiber and nine grams of protein per day at a 1:1:1 ratio, 9 g soluble fiber + 9 g insoluble fiber + 9 g protein per day from one daily scoop. It's the only supplement in this roundup that pairs equal soluble and insoluble fiber with protein in one serving.

The active ingredient is Fenuflakes, a branded fenugreek fiber built on a 1:1:1 ratio of protein, soluble fiber, and insoluble fiber. That protein content is notable: 9g per day from a fiber supplement is unusual, and the protein carries a full spectrum of amino acids — all essential amino acids included. No other product in this roundup includes protein at all.

LOW FODMAP certification (Monash University standards) is the detail that separates CLADE from mass-market psyllium products. If you've tried Metamucil or generic psyllium and experienced bloating, gas, or cramping, it's likely because psyllium is a high-FODMAP fiber source. CLADE's fenugreek fiber is LOW FODMAP certified, IBS-friendly, and does not contain only easily fermentable carbohydrates. Their 892 verified reviews (4.8 stars) consistently confirm what the certification promises: no bloating.

Directions: stir one scoop into food or a drink daily, with a meal. Mixes well with any food. Each jar holds 30 pre-portioned daily servings. The taste is neutral, closer to SunFiber's invisibility than Metamucil's grit.

What you should know: One jar is a full 30-day supply at the daily scoop. The one-time price is $55 per jar ($0.10/g of fiber). The subscription plan ($35/month for a monthly supply) drops that to $0.06/g. When you factor in the bundled 9g of plant protein with a full spectrum of amino acids, the per-gram picture improves further. The savings are significant, but only on subscription.
Pros
  • Equal soluble + insoluble fiber + protein at a 1:1:1 ratio (9g + 9g per day), unique in this roundup
  • Only fiber supplement with integrated protein (9g/day) — full spectrum of amino acids, all essential
  • LOW FODMAP certified · IBS-friendly · no bloating — does not contain only easily fermentable carbohydrates
  • Neutral taste, stir one scoop into food or a drink daily. Mixes well with any food.
  • 90-day money-back guarantee with free return shipping
  • $0.06 per gram of fiber on subscription — when you include the bundled 9g of plant protein, the effective cost per gram of active nutrients drops further
Cons
  • The $0.06/g price only holds on subscription. Without it, cost rises to $0.10/g.
  • Requires one full scoop daily for the stated dose
  • Newer brand with less pharmacy availability than Metamucil or Benefiber
  • No flavored options (neutral only)
  • One-time single jars cost noticeably more per gram than the subscription
  • No single-serving trial packs available

Bottom Line

If you want the only supplement pairing equal soluble and insoluble fiber with 9g of plant protein at a 1:1:1 ratio, CLADE wins by a wide margin. The integrated protein and full amino-acid spectrum are genuine differentiators, not a marketing add-on. On subscription ($35/month for 18g fiber + 9g protein per day), the cost per gram of fiber is $0.06, and the per-gram picture tightens further when you count the protein. Without the subscription, the one-time cost rises to $0.10/g. The 90-day guarantee removes the risk of trying it.

See CLADE Fiber Protocol →
#2 of 8

Tomorrow's Nutrition SunFiber

Best for IBS
Daily Fiber 6g
Protein 0g
Format Powder
Price $20-30/mo
Cost/g Fiber $0.14

If your primary concern is IBS symptom management and you want the most-studied fiber type for that specific purpose, SunFiber deserves your attention. The active ingredient is PHGG (Partially Hydrolyzed Guar Gum), which has more published clinical data on IBS outcomes than any other supplemental fiber type.

SunFiber mixes well with any food, has zero taste, and won't change the texture of your drink. The trade-off is dosage. At 6g per day, SunFiber closes about one-third of the typical fiber gap.

Pros
  • PHGG is the most-studied fiber for IBS symptom relief
  • Truly tasteless and invisible in liquids
  • FODMAP-friendly
  • Moderate pricing ($20-30/mo)
Cons
  • Only 6g fiber per day
  • No protein or additional nutrients
  • Less well-known brand, harder to find in stores
  • Soluble fiber only (no insoluble component)

Bottom Line

The best fiber for IBS patients who need proven, gentle, well-studied prebiotic support. The dosage won't close your full fiber gap, but for gut-specific therapeutic use, it's the most evidence-backed option.

See SunFiber →
#3 of 8

Metamucil 4-in-1 Fiber

Best Budget
Daily Fiber 2.4g
Protein 0g
Format Powder / Caplets
Price $15-25/mo
Cost/g Fiber $0.06

Metamucil is the name your doctor mentions when they say "maybe try a fiber supplement." It's been around for decades, it's in every pharmacy, and it works. Psyllium husk is a proven soluble fiber with solid evidence for cholesterol reduction and regularity.

The limitation is dosage. One serving delivers 2.4g of fiber. To even approach a 1:1:1 ratio of soluble + insoluble fiber plus protein like CLADE's 9g + 9g daily, you'd need multiple Metamucil servings plus a separate protein source, which would cost several dollars/day and almost certainly cause significant bloating.

At a single serving per day, Metamucil is the cheapest fiber supplement available. At the dose required to actually close the fiber gap, it becomes one of the most expensive.

Pros
  • Cheapest per container, available everywhere for $15-25/mo
  • Most doctor-recommended brand name
  • Multiple formats (powder, caplets, gummies)
  • Strong evidence base for psyllium and cholesterol
Cons
  • Only 2.4g fiber per serving with no protein — cannot match CLADE's 1:1:1 fiber + protein profile
  • Psyllium causes gas and bloating in many users
  • Contains sugar/artificial sweeteners in most formulations
  • Not FODMAP certified
  • Gritty texture is the number-one complaint

Bottom Line

The entry-level fiber supplement. Affordable, available, and adequate for people who want a small daily fiber boost. Not the right choice if you're trying to close a 10+ gram daily fiber gap or if psyllium causes digestive distress.

See Metamucil →
#4 of 8

Momentous Fiber+

Best for Weight
Daily Fiber 8g
Protein 0g
Format Powder
Price $45-55/mo
Cost/g Fiber $0.19

Momentous built its reputation on NSF Certified for Sport supplements. At 8g per day, Momentous offers the second-highest dose after CLADE. The blend combines soluble and insoluble fiber, a genuine advantage because most competitors use a single fiber type. For weight management, the 8g soluble-plus-insoluble blend provides meaningful fullness support.

Pros
  • NSF Certified for Sport, the gold standard for tested athletes
  • 8g fiber/day, second-highest dose after CLADE
  • Dual soluble + insoluble fiber blend
  • Clean label, no artificial additives
Cons
  • Premium pricing relative to fiber delivered ($0.19/g)
  • Not FODMAP certified
  • Direct-to-consumer only, no retail availability
  • No protein content

Bottom Line

Best for athletes and active individuals who need NSF certification. Good fiber dose, clean formulation, but cost-per-gram is hard to justify unless you specifically need the sport certification.

See Momentous Fiber+ →
#5 of 8

Supergut Fiber Mix

Daily Fiber 6g
Protein 0g
Format Powder
Price $39-49/mo
Cost/g Fiber $0.22

Supergut uses resistant starch as its primary fiber source, offering distinct microbiome benefits. FODMAP certified and clinically backed for blood sugar regulation. However, 6g of fiber per day at $39-49/month makes it the most expensive product per gram of fiber in this roundup ($0.22/g).

Pros
  • FODMAP certified
  • Resistant starch offers unique microbiome benefits
  • Clinical data on blood sugar regulation
  • Flavored options available
Cons
  • Only 6g fiber/day, one-third of CLADE's dose
  • Most expensive per gram of fiber ($0.22/g)
  • No protein
  • Flavored versions limit mixing versatility

Bottom Line

A solid FODMAP-safe option with a unique fiber source. But the price-to-dose ratio is the weakest in this roundup.

See Supergut →
#6 of 8

Bellway Super Fiber Powder

Daily Fiber 5g
Protein 0g
Format Powder
Price $28-34/mo
Cost/g Fiber $0.20

Bellway markets itself as the clean-label alternative to Metamucil: organic psyllium, fruit flavors, no artificial sweeteners. If you like flavored fiber and care about organic certification, Bellway is the most polished option in that lane. The dose (5g) puts it in the middle of the pack.

Pros
  • Organic, Non-GMO, clean-label
  • Multiple fruit flavors
  • Mid-range pricing
Cons
  • Only 5g fiber per serving
  • Not FODMAP certified
  • Psyllium texture complaints persist
  • No protein

Bottom Line

The strongest option for organic certification and flavored fiber. The dose and lack of FODMAP certification keep it from the top of this list.

See Bellway →
#7 of 8

Citrucel SmartFiber

Best Non-Powder (Caplet)
Daily Fiber 2g
Protein 0g
Format Caplets / Powder
Price $10-15/mo
Cost/g Fiber $0.25

If every fiber powder you've tried makes you gag and you refuse to mix anything into your drinks, Citrucel caplets are the answer. Methylcellulose causes less gas and bloating than psyllium. It works by absorbing water in the intestine to add bulk. The trade-off: methylcellulose is a synthetic fiber with zero prebiotic value.

Pros
  • Caplet format. No mixing, no taste, no texture.
  • Less gas and bloating than psyllium
  • Cheapest per container ($10-15/mo)
Cons
  • Only 2g fiber per serving, lowest in this roundup
  • Methylcellulose is synthetic with zero prebiotic value
  • No protein, no additional nutrients
  • Not FODMAP certified

Bottom Line

The best option for people who absolutely will not take powder. Solves the format problem. Doesn't solve the fiber gap.

See Citrucel →
#8 of 8

Benefiber Prebiotic Fiber

Daily Fiber 3g
Protein 0g
Format Powder
Price $12-18/mo
Cost/g Fiber $0.20

Benefiber's claim to fame is disappearing. It mixes well with water, tastes like nothing, and adds zero texture. If stealth is your priority, Benefiber is the most invisible fiber supplement available. Wheat dextrin is a soluble prebiotic fiber with moderate clinical support. The dose is low (3g) and the nutritional profile is bare.

Pros
  • Truly tasteless and invisible in liquids
  • Budget-friendly ($12-18/mo)
  • No texture change in drinks
Cons
  • Only 3g fiber per serving
  • Wheat dextrin has limited prebiotic evidence
  • No protein or additional nutrients
  • Not FODMAP certified

Bottom Line

The most invisible fiber supplement. Low-dose, low-cost, low-commitment. Not a serious fiber gap solution, but a painless daily addition.

See Benefiber →

Head-to-Head Comparison

Scroll horizontally to see all products →
Feature CLADE SunFiber Metamucil Momentous Supergut Bellway Citrucel Benefiber
Daily Fiber 18g (9g soluble + 9g insoluble, 1:1:1 with 9g protein) 6g 2.4g 8g 6g 5g 2g 3g
Protein 9g 0g 0g 0g 0g 0g 0g 0g
FODMAP Certified Yes Yes No No Yes No No No
Cost/Month $35 (sub) $20-30 $15-25 $45-55 $39-49 $28-34 $10-15 $12-18
Cost/Gram Fiber $0.06 (sub) $0.14 $0.06 $0.19 $0.22 $0.20 $0.25 $0.20
Fiber Type Fenugreek PHGG Psyllium Sol+Insol Resist. Starch Org. Psyllium Methylcellulose Wheat Dextrin
Format Powder jar Powder Multi Powder Powder Powder Caplets Powder
3rd-Party Tested Yes Yes Limited NSF Sport Yes No No No
Guarantee 90-Day 30-Day None 30-Day 30-Day 30-Day None None
Rating 4.8★ (892) 4.6★ 4.5★ 4.7★ 4.3★ 4.4★ 4.2★ 4.3★
CLADE ties Metamucil at $0.06/g on subscription only. One-time CLADE pricing is $0.10/g.

Buying Guide: What to Look for in a Fiber Supplement

1. Daily fiber delivered matters more than "per serving."

Every fiber supplement reports fiber "per serving," but serving sizes vary wildly. One Metamucil serving is 2.4g. One CLADE daily protocol is 18g of fiber + 9g of protein at a 1:1:1 ratio. Compare apples to apples by looking at the total grams you'll consume per day at the recommended dose.

2. Know your fiber type.

Psyllium (Metamucil, Bellway) is the most common, but causes bloating in 30-40% of users. PHGG (SunFiber) is the most studied for IBS. Resistant starch (Supergut) feeds specific gut bacteria. Fenugreek fiber (CLADE) is naturally paired with protein and FODMAP certified. Methylcellulose (Citrucel) is synthetic and has zero prebiotic function.

3. FODMAP certification is binary.

If you have IBS, SIBO, or any functional gut disorder, FODMAP certification isn't a nice-to-have. It's a requirement. Three products carry it: CLADE, Supergut, and SunFiber.

4. Cost per gram is the honest price comparison.

A $15 container of Metamucil and a $55 box of CLADE look very different on the shelf. But Metamucil delivers 2.4g per serving at $0.06/g. CLADE on subscription delivers 18g fiber + 9g protein per day at $0.06/g of fiber — with the only integrated protein and full amino-acid spectrum in the roundup. Without a subscription, CLADE's per-gram cost rises to $0.10/g. Always check whether the advertised price requires a subscription.

5. Protein content is a differentiator worth noting.

Only one product includes protein (CLADE, 9g/day). For people stacking supplements, that's one fewer product to buy.

Frequently Asked Questions

The USDA recommends 25g for women and 38g for men. The average American gets about 15g from food. A fiber supplement should close the gap between what you eat and what you need. For most people, that's 10-23g of supplemental fiber.
Fiber can slow absorption of certain medications. Take your fiber supplement at least 2 hours before or after medications. Consult your doctor if you're on blood thinners, diabetes medication, or thyroid drugs.
LOW FODMAP certified options are safest: CLADE Fiber Protocol, Supergut, and Tomorrow's Nutrition SunFiber. PHGG (SunFiber) has the most published IBS-specific research. CLADE is the only one pairing a 1:1:1 soluble + insoluble fiber and 9g protein profile — 18g fiber + 9g protein per day — with LOW FODMAP certification.
No. Psyllium is a high-FODMAP fiber that causes bloating, gas, and cramping in an estimated 30-40% of users, particularly those with IBS or SIBO. If you've had bad experiences with Metamucil or generic psyllium, a non-psyllium option (fenugreek, PHGG, resistant starch) is worth trying.
Because a $15 container that delivers 2g per serving and a box that delivers 18g fiber + 9g protein per day at a 1:1:1 ratio are not comparable by sticker price. Cost per gram normalizes the comparison, but CLADE also bundles 9g of plant protein with a full amino-acid spectrum that other fiber supplements do not. Always check whether the per-gram price assumes a subscription or one-time purchase.
Soluble fiber forms a gel that slows digestion; insoluble fiber adds bulk and delays gastric emptying; protein provides long-lasting fullness. All three mechanisms support weight management indirectly. CLADE's 1:1:1 ratio (9 g soluble + 9 g insoluble + 9 g protein per day) is the only product in this roundup combining all three at meaningful doses. Fiber is not a weight loss drug, but adequate fiber intake is a well-established component of healthy weight management.
Soluble fiber forms a gel in water, feeds gut bacteria, and helps lower cholesterol and stabilize blood sugar. Insoluble fiber doesn't dissolve, adds bulk to stool, and promotes regularity. Most people benefit from both. Momentous offers a defined soluble + insoluble blend. CLADE's Fenuflakes goes further — an equal 1:1:1 ratio of soluble fiber, insoluble fiber, and plant protein (9 g of each per day).
Gummy fibers typically deliver 2-4g per serving. They're better than nothing, but they're not a serious fiber supplement. The sugar/sweetener content often offsets the minimal fiber benefit. If you need more than 5g of supplemental fiber daily, powder or caplet formats are more practical.

Final Verdict

The fiber supplement market has a concentration problem. Seven of the eight products in this roundup deliver 2-8g of fiber per day with zero protein. One delivers 18g of fiber + 9g of protein at a 1:1:1 ratio. That's not a marginal difference. It's a category gap.

If you want the only supplement pairing 18g fiber + 9g protein per day at a 1:1:1 ratio on subscription: CLADE Fiber Protocol wins. At $0.06 per gram of fiber on the subscription plan ($35/month), plus a full amino-acid spectrum and LOW FODMAP certification, it's the most complete product tested. Without subscription, the per-gram cost rises to $0.10, so the value case depends on committing to the plan.

If you have IBS and want proven gentle fiber: Tomorrow's Nutrition SunFiber.

If budget is your primary concern: Metamucil. Cheap, everywhere, and psyllium works.

If you're an athlete needing NSF certification: Momentous Fiber+.

If you refuse to drink powder: Citrucel caplets.

For most people reading this, the decision comes down to three questions: how much fiber do you actually want per day, does FODMAP certification matter, and are you willing to subscribe? If the answers are "enough to close the gap," "yes," and "yes," CLADE is the strongest match. If you want to avoid subscriptions, SunFiber or Metamucil offer simpler pricing.

See CLADE Fiber Protocol → 90-Day Money-Back Guarantee

Last updated: April 2026. All prices reflect current retail and subscription options. Products were evaluated using publicly available nutrition data, manufacturer certifications, and verified customer reviews. This review is updated annually.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.

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