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Microbiome

Prebiotic Fiber · Inulin / FOS / GOS

Feeds beneficial gut bacteria; go slow to avoid gas.

B
Evidence grade
Human RCTs, biomarker outcomes

Short answer

Start low (2 to 3 g/day) and ramp up. Sudden 10 g doses cause gas.

Product and dose overview

Prebiotic Fiber (Inulin / FOS / GOS) is a microbiome with evidence grade B, meaning it is supported by human RCTs. We track 3 products containing Prebiotic Fiber. Typical doses range from 20 to 4000 mg per serving. The top-ranked product scores 7.2 out of 10 on our composite scale (dose, evidence, price, testing, transparency). Prices range up to $69.00 per month.

Evidence grade: B Products in database: 3 Category: Microbiome

Top Prebiotic Fiber products

ProductBrandDosePrice/mo3rd-party testedScore
NOVOS VitalNOVOS Labs4000 mg$69.00Yes7.2
Nordic Flora Probiotic DailyNordic Naturals20 mg$30.95Yes5.0
ProbioticDoNotAge100 mg$24.99No4.8

Scores are editorial judgments, not a scientific standard. See how we score.

What it is

Fiber that resists digestion until your gut bacteria ferment it.

Why people take it

Trials show shifts in microbiota and short-chain fatty acid production. Digestive tolerance improves over weeks.

Our verdict

Start low (2 to 3 g/day) and ramp up. Sudden 10 g doses cause gas.

Structure & class

Inulin, fructooligosaccharides, galactooligosaccharides.

Mechanism & clinical data

Bindels 2015 review documented microbiota shifts.

Pharmacokinetics

Transit.

Dose & forms

Trial dose
5000 mg
/ day
Range in trials
2000 to 15000 mg
/ day
Common forms
Inulin powder, FOS/GOS blend

What to watch out for

FODMAP sensitivity common. Titrate slowly.

Where this dose comes from

The trial dose above is our editorial pick from the published human trials for this ingredient. We choose the dose that the best-available studies used on the endpoint most relevant to longevity. The range shows the lowest and highest doses tested in published trials. The landmark studies below are the papers we read to set it. You can click through and check our work.

When new trials publish, our automated sweeps flag them. If a new study materially changes the dose, we update it through editorial review and record the old dose, new dose, and the triggering study in every affected product's recommendation history. The dose is never changed automatically.

Regulatory status

EUFood supplement
USDietary supplement
UKFood supplement
CANHP

Timeline

Regulatory events, evidence grade changes, and key research milestones for Prebiotic Fiber, most recent first. Studies link to the paper; regulatory entries name and link the responsible authority.

  • 2025-04 Regulatory single source
    EU Court sharpens the bar for botanical health claims
    A Court of Justice of the European Union ruling in April 2025 further tightened the requirements for how botanical ingredients (herbs, plant extracts) can be marketed with health claims in the EU, effectively removing much of the flexibility of the on-hold list.
  • 2024-06 Regulatory confirmed
    EU report identifies 117 supplement substances as potential health risks
    The HoA Working Group on Food Supplements (26 European countries) published its first report evaluating 117 substances used in food supplements. Of these, 65 were assessed as likely novel foods, 6 were already regulated, 34 had insufficient data, and 12 were prioritized for Article 8 restriction under Regulation (EC) No 1925/2006. The 12 priority substances include ashwagandha, curcumin, melatonin, piperine, St. John's wort, coumarin, p-synephrine, maca, holy basil, Melaleuca, black cohosh, and L-tryptophan. The report drew on 1,500 RASFF alerts reviewed between 2017 and mid-2022.
    Source →
  • 2006-12 Regulatory confirmed
    EU Health Claims Regulation adopted
    Regulation (EC) No 1924/2006 laid down harmonised rules for nutrition and health claims made on foods, including supplements. Only claims listed in the EU Register of authorised claims can be used. Rejected botanical claims are held in a separate on-hold list.
    Source →
  • 1997 Regulatory confirmed
    EU introduces the Novel Food Regulation
    Regulation (EC) No 258/97 required any food or food ingredient without a history of consumption in the EU before 15 May 1997 to be authorised before being placed on the market. This is the framework that captures NMN, spermidine as a supplement ingredient, urolithin A, and many other longevity actives.
    Source →

Landmark studies

Found in these products (3)

All products in our catalog that contain Prebiotic Fiber, ranked by our overall score. Ranking is editorial, never paid.

NOVOS Labs
NOVOS Vital
Multi/greens
Ingredients listed
1 ingredients listedlargest listed: Prebiotic Fiber 4,000 mg
Price per serving
$2.30$69.00 · 30 servings
Testing
3rd-party listed · no public lab certificate

Multi-ingredient bundle

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 7.2/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

100%
of trial dose
$2.88
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with novoslabs.com
Multi/greens
Ingredients listed
1 ingredients listedlargest listed: Prebiotic Fiber 20 mg
Price per serving
$1.03$30.95 · 30 servings
Testing
3rd-party listed · no public lab certificate

CFU not stored

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 5.0/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

1%
of trial dose
$257.92
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with www.nordic.com
DoNotAge
Probiotic
Metabolic
Active per serving
Prebiotic Fiber 100 mgCapsule · 366 servings
Price per serving
$0.07$24.99 · 366 servings
Testing
None listed

CFU not stored

Status as recorded in the catalog from brand materials; not independently verified by NO1GEVITY.

Score & research context 4.8/10

Editorial score, not proof that this product works. Research-dose calculations are not dosing advice.

5%
of trial dose
$3.41
per research-dose day, not label serving
0Trial dose2×
Catalog price · Confirm current price with donotage.org
Editorial guides

Buying guides and comparisons

Neighbouring molecules

Related ingredients

See all in Microbiome →

Molecules in the same class, plus the actives most often formulated alongside Prebiotic Fiber in our catalogue.

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Product shelves
See all in Multi/greens (2)See all in Metabolic (1)

See Prebiotic Fiber in context: the mechanism it acts through, the biomarker it moves, the products that dose it, and the trials that tested it.

View Prebiotic Fiber on the Longevity Map →

Frequently asked questions

What is Prebiotic Fiber?

Fiber that resists digestion until your gut bacteria ferment it.

What dose of Prebiotic Fiber should I take?

The trial dose in published human studies is 5000 mg per day, with a range of 2000 to 15000 mg per day. Always consult a qualified clinician before starting any supplement.

Is Prebiotic Fiber safe?

FODMAP sensitivity common. Titrate slowly.

What is the best Prebiotic Fiber supplement?

We track 3 products containing Prebiotic Fiber. The top-ranked product scores 7.2 out of 10 on our composite scale, which evaluates dose, evidence, price, third-party testing, and transparency. See the comparison table above. Scores are editorial judgments, not a scientific standard.

What is the evidence grade for Prebiotic Fiber?

Prebiotic Fiber has evidence grade B, meaning it is supported by human RCTs. Grade A means replicated human RCTs with hard endpoints. Grade B means human RCTs with biomarker outcomes. Grade C means mixed or small human trials. See our evidence grading methodology.

Independently checked

Data verification

Evidence grade
B
Human RCTs, biomarker outcomes
Research dose
5000 mg
Products tracked
3
Updated continuously
Safety signal
FODMAP sensitivity common. Titrate slowly.

Evidence grades are reviewed when new human RCTs are published. Product counts update automatically as new products are added. Dose ranges reflect published trial data, not brand recommendations. Read how we verify.