Daily gut routine

NOW Foods Inulin Prebiotic Pure Powder

A cheap, single-ingredient chicory fiber with constipation trials behind it and a well-earned reputation for gas.

Format: Powder, once a day
Type: Prebiotic
Cost: $0.16 a day
Customer rating: 4.6 out of 5 from 5,620 ratings from Amazon

What customers consistently report

Regularity improving within a week or two
A mild sweetness that disappears into coffee or a smoothie
Costing pennies a day

Those are the themes that recur across the reviews. High review confidence — 4.6 from 5,620 Amazon ratings on the 8 oz listing.

Why it might work

Inulin passes the small intestine undigested and is fermented quickly by colonic bacteria, especially bifidobacteria, producing short-chain fatty acids and gas. The fermentation draws water and adds bacterial mass to stool, which is the laxative effect; the gas is the same process and cannot be separated from it. Slower-fermenting fibers such as PHGG or acacia trade some of the effect for less discomfort.

What the research supports

Ingredient-level evidence. A meta-analysis of randomized trials in constipation found inulin improved stool frequency, consistency and transit time against placebo. A 2016 placebo-controlled trial of chicory inulin in constipated adults found more frequent, softer stools. A 2025 randomized trial in constipation-predominant IBS using 9.2 g a day of an inulin-oligofructose mix improved symptom severity and quality of life. The gas side effect appears in all of them. No trial of this brand was found.

What the label discloses

The only ingredient is certified organic chicory inulin (FOS); Non-GMO Project verified. A teaspoon is roughly 4 g and the label says one teaspoon or more as required. No third-party testing certificate is published beyond the organic and non-GMO marks.

Who this tends to suit

We match this product to people reporting constipation and irregular bowel habits. It fits someone whose priority is regularity or a steady daily routine. Whether it is the best fit for you depends on the rest of your answers — what you have already tried, what format you will take, and anything that has to be ruled out.

Where it may not fit

The label supports vegan, gluten-free, dairy-free, no added sweeteners and minimal ingredient list. A powder only works if you will take it once a day, every day.

Side effects and what to be aware of

Inulin is fermented fast, which is the point and the problem: gas and bloating are the commonest complaints, and anyone whose bloating is the main symptom, or who is sensitive to FODMAPs, will usually feel worse rather than better. Start at a teaspoon and build slowly. It is a regularity product, not a comfort one.

Buy it at iHerb

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