Best Fiber Supplements 2026: Cost per Effective Dose
Top pick for Fiber: NOW Psyllium Husk Powder, Organic (12 oz) — 7g per 1 tbsp (9 g), Non-GMO Project Verified, USDA Organic, $0.37/day. Our best-value pick.
All Fiber Supplements Compared
The fibre type matters more than the brand. Fermentable fibres such as inulin have the stronger prebiotic evidence and reliably feed bifidobacteria, but they also produce the gas and bloating people blame on the product; wheat dextrin and methylcellulose ferment far less and are much better tolerated at the cost of a weaker prebiotic effect. Whichever you choose, build up over a week or two — starting at a full serving is the usual reason a fibre supplement gets abandoned. This page compares fibre types against each other; if you have already settled on psyllium and just want the cheapest way to take it, the psyllium husk comparison covers whole husk, powder and capsules side by side.
All 6 products sorted by cost per labelled serving (lowest first). Dose, certification, and pricing verified against NIH DSLD and manufacturer data.
Read the dose column before the price column. Servings in this category are not equivalent — they range from 2 to 7 g per serving. A lower cost per day here can simply mean a smaller serving, so the cheapest row is not automatically the best value.
| Product | Brand | Dose / Serving | Cost / Day | Certification | Pick | Buy |
|---|---|---|---|---|---|---|
| NOW Organic Inulin Prebiotic Powder (8 oz) | NOW Foods | 3g / 1 tsp (~3 g) | $0.13 | USDA Organic, Non-GMO | Buy | |
| Benefiber Prebiotic Fiber Powder (wheat dextrin) | Benefiber | 3g / 2 tsp (~3.5 g) | $0.22 | None listed | Buy | |
| Metamucil 4-in-1 Psyllium, Sugar-Free (72 servings) | Metamucil | 3.4g / 1 rounded tsp (~5.8 g) | $0.25 | None listed | Buy | |
| Konsyl Daily Psyllium Fiber Powder (19 oz) | Konsyl | 5g / 1 tsp (6 g) | $0.29 | Single-ingredient psyllium | Quality Pick | Buy |
| NOW Psyllium Husk Powder, Organic (12 oz) | NOW Foods | 7g / 1 tbsp (9 g) | $0.37 | Non-GMO Project Verified, USDA Organic | Best Value | Buy |
| Citrucel Methylcellulose Fiber Powder | Citrucel | 2g / 1 tbsp (2 g fiber) | $0.62 | FDA OTC monograph drug | Buy |
Our Picks
Best Value: NOW Psyllium Husk Powder, Organic (12 oz)
7g per 1 tbsp (9 g). Non-GMO Project Verified, USDA Organic. $0.37/day. 38 servings per container at $14.10.
Quality Pick: Konsyl Daily Psyllium Fiber Powder (19 oz)
5g per 1 tsp (6 g). Single-ingredient psyllium. $0.29/day. 90 servings per container at $25.99.
How We Rank Fiber Supplements
Every product is evaluated on three criteria:
- Cost per day. Not cost per pill or cost per bottle — what it actually costs per day at the product's labelled serving. Where a category's servings differ in strength we flag it above the table, because cost per day is only comparable when the doses are.
- Third-party certification. USP Verified, NSF Certified for Sport, and ConsumerLab Approved indicate independent testing for purity, potency, and contaminants.
- Bioavailable form. We prioritize products using the specific chemical form shown to be most effective in published research.
Rankings are not influenced by affiliate commissions. We earn the same commission regardless of which product you choose. Read our full methodology.
Personalize Your Fiber Choice
Not sure which fiber supplement is right for you? Use our free tools:
- DNA Supplement Analyzer — upload 23andMe or AncestryDNA data to check for genetic variants affecting fiber metabolism. Runs entirely in your browser.
- Lab Results Interpreter — enter your blood test values to get personalized dosing recommendations.
- Supplement Stack Builder — build a complete protocol based on your age, sex, medications, and goals.
- Supplement Audit — already taking fiber? Check if you have the right form and dose.