The 4 Best Fiber Supplements of 2026
The best fiber supplement for most people is Konsyl Daily Psyllium Fiber Powder: 5 g of fiber a teaspoon for $0.43, on NSF/ANSI 173. It is plain psyllium, the fiber with the best evidence for constipation. Build up to 3 teaspoons (15 g) a day, with a full glass of water each time.
By Erin Rose Updated October 12, 2026 How we score
Our picks at a glance
Our pick for: Most people
Konsyl Daily Psyllium Fiber Powder
9.0/10 Our score
9.0/10, the top score of the 11 psyllium powders we score
Good
- On the NSF/ANSI 173 list (checked October 6, 2026)
- Full serving: 5 g per serving (we count 5 g or more)
- Label states the amount, with no blend
Watch for
- Costs 1.9 times as much per dose as the cheapest of its kind we score
- Fiber
- 5 g a teaspoon3 g of it soluble
- A serving
- $0.431 teaspoon, list price
- Testing list
- NSF/ANSI 173
- In the tub
- Psyllium husknothing added
- Tub
- 60 teaspoons, $25.99walgreens.com list price, 12.7 oz tub; the Amazon link is the 19 oz tub
- Per 10 g of fiber
- $0.872 teaspoons
Our take
Why we pick it Psyllium has the best evidence of any fiber for constipation, though it is still rated low certainty. Of the fibers with trials (psyllium, bran and inulin), US gut doctors’ 2023 guideline found that only psyllium appears to be effective: about 2 more bowel movements a week than a placebo (AGA-ACG 2023). In trials, more than 10 g of fiber a day, taken for at least 4 weeks, helped constipation; 10 g a day or less did not (BDA 2025; van der Schoot 2022). This tub is psyllium and nothing else, 5 g of fiber a teaspoon, and it is on NSF/ANSI 173, which checks that it holds what the label says.
What you give up A little money. NOW Whole Psyllium Husks, below, costs $0.51 per 10 g of fiber against $0.87 here, but it is not on a testing list. Fiber also causes gas at first (van der Schoot 2022): start with one teaspoon a day and build up to 3 teaspoons (15 g), the most the label allows.
One more thing Stir each teaspoon into a full glass of water (8 oz) and drink it right away. Psyllium swells, and with too little water it can block the throat (the label warning; FDA rule 21 CFR 201.319). Do not take it if you have trouble swallowing. Take other medicines 2 hours before or after. All the cautions.
Testing record
- NSF/ANSI 173: contents match the label Checked October 6, 2026.
Lists searched September 22, 2026 to October 6, 2026.
Safety: Take psyllium with a full glass of water. Do not take it if you have trouble swallowing. Take other medicines 2 hours before or after. All the cautions.
Our other 3 picks
Each is for a different need: the same psyllium for less, or a fiber to try if other fiber gives you gas.
- If you want organic NOW Psyllium Husk Powder, Organic
- Plain psyllium for less NOW Whole Psyllium Husks
- If other fiber gives you gas Tomorrow's Nutrition Sunfiber
Our pick for: If you want organic
Good
- Full serving: 7 g per serving (we count 5 g or more)
- Label states the amount, with no blend
- No FDA recall for the brand in 24 months
Watch for
- Not on any public testing list we check
- Costs 1.6 times as much per dose as the cheapest of its kind we score
- Fiber
- 7 g a serving1 level tablespoon (9 g)
- A serving
- $0.53brand list price
- Testing list
- None found
- Type
- Psyllium huskorganic powder, nothing added
- Size
- 12 oz tub, $19.99NOW’s list price
- Per 10 g of fiber
- $0.752 servings
Our take
Certified organic plain psyllium husk powder: 7 g of fiber in 1 level tablespoon (9 g), for $0.75 per 10 g of fiber at NOW’s list price ($0.53 a serving). It is the same kind of fiber as our pick. It costs more per 10 g than the whole husks below, and it is not on a public testing list.
Testing record
Not found on any testing list we check.
Lists searched September 22, 2026 to October 6, 2026.
Our pick for: Plain psyllium for less
Good
- Full serving: 7 g per serving (we count 5 g or more)
- Close to the lowest cost per dose (1.1 times the cheapest of its kind we score)
- Label states the amount, with no blend
Watch for
- Not on any public testing list we check
- Fiber
- 7 g a serving2 level tablespoons (10 g)
- A serving
- $0.36brand list price
- Testing list
- None found
- Type
- Psyllium huskwhole husk, nothing added
- Size
- 16 oz tub, $15.99NOW’s list price
- Per 10 g of fiber
- $0.512 servings
Our take
The same plain psyllium husk as our pick, as whole husk flakes: 7 g of fiber in 2 level tablespoons (10 g), for $0.51 per 10 g of fiber at NOW’s list price. That is $0.36 a serving. Of the plain psyllium products that score 7 or more, it costs the least per 10 g of fiber. Stir it into a full glass of water or juice and drink it right away.
Testing record
Not found on any testing list we check.
Lists searched September 22, 2026 to October 6, 2026.
Our pick for: If other fiber gives you gas
Tomorrow's Nutrition Sunfiber
8.0/10 Our score
8.0/10, tied for the top score of the 13 other fiber powders we score
Good
- On the Informed Choice list (checked October 6, 2026)
- Full serving: 6 g per serving (we count 5 g or more)
- Label states the amount, with no blend
Watch for
- Costs 3.7 times as much per dose as the cheapest of its kind we score
- Fiber
- 6 g a serving1 scoop (7 g)
- A serving
- $0.83brand list price
- Testing list
- Informed Choice
- Type
- PHGG (guar fiber)dissolves clear
- Size
- 30-day (210 g) tub, $24.99Sunfiber’s list price
- Per 10 g of fiber
- $1.392 servings
Our take
6 g of guar fiber (PHGG) a scoop, on Informed Choice. The label says it dissolves clear, with no grit. In one trial in people with IBS, 6 g a day eased bloating more than a placebo, though overall symptoms did not improve (Niv 2016). If you have IBS, ask your doctor which fiber to try. Try psyllium first if you can. $0.83 a scoop at list price.
Testing record
- Informed Choice: banned substances, monthly retail samples Checked October 6, 2026.
Lists searched September 22, 2026 to October 6, 2026.
Which one is for you?
| Your situation | What to buy |
|---|---|
| Constipation, or you eat little fiber | 5 g of fiber a teaspoon, so 2 teaspoons is 10 g. In trials, more than 10 g of fiber a day, taken for at least 4 weeks, helped constipation; 10 g a day or less did not (BDA 2025; van der Schoot 2022). Start with 1 and build up to 3 teaspoons a day (15 g), the most the label allows: $1.30 a day at list price. Our pick: Konsyl Daily Psyllium Fiber Powder (above). |
| Price matters most | The same plain psyllium for less: NOW Whole Psyllium Husks, $0.51 per 10 g of fiber (above). |
| You want organic | Plain USDA organic psyllium, 7 g of fiber in a level tablespoon, $0.75 per 10 g: NOW Psyllium Husk Powder, Organic (above). |
| Psyllium gives you gas | Methylcellulose, a fiber gut bacteria do not ferment (Dellschaft 2026); fermenting is what makes gas (ACG 2021): Citrucel Methylcellulose Fiber Powder. Or guar fiber, which dissolves clear: Tomorrow's Nutrition Sunfiber, $0.83 a scoop (above). |
| You want fiber you cannot taste | Wheat dextrin dissolves fully. It adds fiber but does not act as a laxative (McRorie and McKeown 2017). On NSF/ANSI 173, $1.07 per 10 g: Benefiber Prebiotic Fiber Powder, Unflavored. |
| You want it flavored | Psyllium with a sweetener (aspartame), 3 g of fiber a rounded teaspoon. The label allows up to 3 a day, about 9 g. $0.88 per 10 g: Metamucil 4-in-1 Psyllium Powder, Sugar-Free Orange. |
| You want a prebiotic | Inulin feeds gut bacteria but is not a laxative, and it can bring gas (BDA 2025). Start with a teaspoon, 4 g of fiber, $0.75 per 10 g: NOW Organic Inulin Prebiotic Powder. |
| You will only take a gummy | Gummies add fiber, but their fibers (polydextrose and inulin) did not help constipation in UK dietitians’ review (BDA 2025). The tested ones are on our testing page. |
Two of our four picks (Konsyl and Sunfiber) are on a public testing list (NSF, USP or Informed); both NOW products are not. Which fiber is on which list.
| Item | Value |
|---|---|
| NOW whole husk | $0.51 |
| NOW inulin | $0.75 |
| NOW psyllium | $0.75 |
| Konsyl psyllium | $0.87 |
| Metamucil sugar-free | $0.88 |
| Benefiber wheat dextrin | $1.07 |
| Sunfiber PHGG | $1.39 |
Metamucil, Benefiber and Citrucel
Metamucil is psyllium too, with sugar or a sweetener added. A rounded teaspoon of the sugar-free kind gives 3 g of fiber. The label allows up to 3 a day, about 9 g. It costs $0.88 per 10 g of fiber at Walgreens’ price, close to our pick.
Benefiber is on NSF/ANSI 173, but it is wheat dextrin, a fiber that dissolves fully and does not form a gel. Reviews find it does not act as a laxative and can even constipate (McRorie and McKeown 2017). Buy it to add fiber you cannot taste, not for constipation.
Citrucel is methylcellulose, sold as a drug for constipation. It worked as a laxative at doses as low as 1 g a day in a trial in constipated people (Hamilton 1988), and gut bacteria do not ferment it. The powder’s label gives no serving weight or count, so we could not price it per gram; the caplets cost $4.40 per 10 g. Every type compared.
Where we disagree with the big guides
Yahoo Health’s best overall is a psyllium blend with probiotics that it marks as third-party tested. We did not find that brand on the NSF, USP or Informed lists. Its pick for constipation is Metamucil 4-in-1, which is psyllium, as ours is. Its gut-health pick is on NSF Certified for Sport (our testing page). We read the guide on October 6, 2026.
The 7 we show, out of the 36 we score, and how we checked them
| Product | Score | Fiber | Per 10 g | Testing list | Size and list price | Buy |
|---|---|---|---|---|---|---|
| Konsyl Daily Psyllium Fiber PowderKonsyl · psyllium powder · psyllium husk | 9.0/10 | 5 g1 teaspoon (6 g) | $0.87 | NSF/ANSI 173 | 60-serving bottle, $25.99 | Buy on Amazon |
| NOW Whole Psyllium HusksNOW · psyllium powder · psyllium husk | 7.0/10 | 7 g2 level tablespoons (10 g) | $0.51 | Not found* | 16 oz tub, $15.99 | Buy on Amazon |
| Tomorrow's Nutrition SunfiberSunfiber · other fiber · PHGG (guar fiber) | 8.0/10 | 6 g1 scoop (7 g) | $1.39 | Informed Choice | 30-day (210 g) tub, $24.99 | Buy on Amazon |
| NOW Psyllium Husk Powder, OrganicNOW · psyllium powder · psyllium husk | 6.0/10 | 7 g1 level tablespoon (9 g) | $0.75 | Not found* | 12 oz tub, $19.99 | Buy on Amazon |
| Metamucil 4-in-1 Psyllium Powder, Sugar-Free OrangeMetamucil · psyllium powder · psyllium husk | 4.5/10 | 3 g1 rounded teaspoon (5.8 g) | $0.88 | Not found* | 113-serving bottle, $29.99 | Buy on Amazon |
| Benefiber Prebiotic Fiber Powder, UnflavoredBenefiber · other fiber · wheat dextrin | 6.5/10 | 3 g2 teaspoons (4 g) | $1.07 | NSF/ANSI 173 | 8.7 oz tub, $19.99 | Buy on Amazon |
| NOW Organic Inulin Prebiotic PowderNOW · other fiber · inulin | 4.5/10 | 4 g1 level teaspoon (about 4 g) | $0.75 | Not found* | 8 oz tub, $16.99 | Buy on Amazon |
* Not found on the public NSF, USP or Informed lists (searched September 22, 2026 to October 6, 2026). More: which fiber is on which list and the best psyllium.
The score. Five marks: does a serving give at least 5 g of fiber, which we count as a full serving (constipation trials used more than 10 g a day; this line is ours); is the product on a public testing list (a brand’s own testing claim, with no listing, earns half the 3 points); what 10 g of fiber costs against the cheapest in its group; does the label state the amounts; and any FDA recall naming the brand. Dose and testing are worth up to 3 points each, cost up to 2, label and recalls up to 1 each, for 10 in all. A score says nothing about which fiber type works; the text above does. How we score.
Not scored, and why.
- Konsyl Organic Daily Psyllium Fiber: On NSF/ANSI 173, but Konsyl sells through retailers and we found no retailer price (October 6, 2026).
- BulkSupplements Organic Psyllium Husk Powder: On NSF/ANSI 173 and NSF Certified for Sport. We score only products with a price we could check, and we had none for this powder (October 6, 2026).
- Benefiber Caplets: On NSF/ANSI 173, but we could not confirm the fiber per caplet from the label.
- Citrucel Powder (orange and sugar-free): Its drug label gives 2 g of methylcellulose per heaping tablespoon but no serving weight or servings per tub, so a cost per gram cannot be worked out. We score Citrucel caplets instead.
- Kirkland Signature Fiber Capsules: No regular price we could confirm.
- up&up Psyllium Fiber Capsules (Target): Sold only at Target, not on Amazon, so we cannot link it.
- Konsyl Daily Psyllium Fiber Capsules: No retailer price found.
- Organic India Psyllium Capsules: No US price found.
- Nutricost Psyllium Husk powder and capsules: No price we could confirm.
- Anthony's psyllium and inulin powders: No label we could confirm the fiber grams from.
- Kate Naturals Organic Psyllium Husk Powder: No label we could confirm the fiber grams from, and no regular price.
- It's Just! Psyllium Husk Powder: No price or label we could confirm.
- Regular Day Sunfiber: On Informed Choice, but sold only on Amazon and we found no label or regular price to score.
- LOAM Prebiotic Fiber Formula: On NSF/ANSI 173, but Amazon lists it as not yet available (October 6, 2026).
- Heather's Tummy Fiber (acacia): Sold as a medical food, and we found no store listing we could match to its label.
- Metamucil Fiber Thins and Premium Blend: No retailer price found.
- Amazon Basics Fiber Gummies: No brand or store list price.
- OLLY Kids Friendly Fiber and SmartyPants Kids Digestive Fiber: Children's products. These pages cover adults.
- Glucomannan capsules (NOW, Nutricost, Nature's Way): Sold for weight loss, where a review of trials found no real effect (about 0.2 kg; Onakpoya 2014). Not part of these guides.
More: fiber types compared, the best psyllium, how much fiber a day and which fiber is third-party tested (including one for drug-tested athletes).
Sources
- Chang L, et al. AGA-ACG Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation. Gastroenterology. 2023. PubMed 37211380
- Dimidi E, et al. British Dietetic Association guidelines for the dietary management of chronic constipation in adults. J Hum Nutr Diet. 2025. PubMed 41081513
- van der Schoot A, et al. The effect of fiber supplementation on chronic constipation in adults: an updated systematic review and meta-analysis. Am J Clin Nutr. 2022. PubMed 35816465
- Lacy BE, et al. ACG Clinical Guideline: Management of Irritable Bowel Syndrome. Am J Gastroenterol. 2021. PubMed 33315591
- Niv E, et al. Randomized clinical study: partially hydrolyzed guar gum (PHGG) versus placebo in the treatment of patients with irritable bowel syndrome. Nutr Metab (Lond). 2016. PubMed 26855665
- Jovanovski E, et al. Effect of psyllium (Plantago ovata) fiber on LDL cholesterol and alternative lipid targets, non-HDL cholesterol and apolipoprotein B: a systematic review and meta-analysis of randomized controlled trials. Am J Clin Nutr. 2018. PubMed 30239559
- Gibb RD, et al. Psyllium fiber improves glycemic control proportional to loss of glycemic control: a meta-analysis of data in euglycemic subjects, patients at risk of type 2 diabetes mellitus, and patients being treated for type 2 diabetes mellitus. Am J Clin Nutr. 2015. PubMed 26561625
- McRorie JW Jr, McKeown NM. Understanding the Physics of Functional Fibers in the Gastrointestinal Tract. J Acad Nutr Diet. 2017. PubMed 27863994 (McRorie is listed at Procter & Gamble, which makes Metamucil, on a 2015 paper (Gibb 2015, PubMed 26561625).)
- Dellschaft N, et al. Randomised Placebo-Controlled Trial of Methylcellulose and Psyllium Gels on Inulin-Induced Colonic Gas. Aliment Pharmacol Ther. 2026. PubMed 42728685
- Hamilton JW, et al. Clinical evaluation of methylcellulose as a bulk laxative. Dig Dis Sci. 1988. PubMed 2839321
- FDA. 21 CFR 201.319, warning for water-soluble gums and hydrophilic gums used as active ingredients (eCFR, read October 6, 2026). Metamucil drug facts label (DailyMed, read October 6, 2026).
- Other guide, read October 6, 2026: Yahoo Health, “We tested 20 fiber supplements” (updated May 1, 2026).
- Labels: each brand’s page, the NIH Dietary Supplement Label Database or DailyMed. Testing: NSF/ANSI 173, NSF Certified for Sport and Informed Choice, read October 6, 2026; Informed Sport and USP Verified as listed on September 22, 2026. Recalls: openFDA. Prices: each brand’s own list price (Walgreens, iHerb, Vitacost or Sam’s Club where named), checked October 6, 2026.