Fructooligosaccharides (FOS)
Also known as: FOS, fructo-oligosaccharides, oligofructose, scFOS, short-chain fructooligosaccharides, NutraFlora, Orafti P95
Fructooligosaccharides are short-chain fructans produced either by partial hydrolysis of chicory inulin (oligofructose) or by enzymatic synthesis from sucrose (scFOS). Their short chain length makes them rapidly fermentable, mildly sweet, and highly soluble, so they are used both as a prebiotic and as a partial sugar replacer in gummies, chews, and flavored powders. Dose-response work in healthy adults found bifidogenic effects across 2.5–10 g per day, with gas and bloating rising at the top of that range. FOS often pairs with probiotics in synbiotic formulas.
Research summary
Rapidly fermented in the proximal colon by bifidobacteria and lactobacilli to short-chain fatty acids; studied for effects on microbiota composition and mineral absorption.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| 2.5 g | 2.5–10 g | — | — |
Begin at 2–3 g per day and increase gradually; most people tolerate 5 g without symptoms, while 10 g or more commonly produces gas. Take with meals. Because FOS ferments quickly it tends to cause more bloating per gram than long-chain inulin.
Standardization: ≥95% FOS (dry basis) for scFOS; oligofructose typically ≥90%
Source material: chicory root (oligofructose) or enzymatically from sucrose (scFOS)
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
About 30–50% as sweet as sucrose; useful as a bulking sweetener in gummies and chews. Hygroscopic powder.
Formulation notes
Hygroscopic; protect probiotics in the same fill from moisture. High-FODMAP; not suited to low-FODMAP positioning.
Sources
- The capacity of nondigestible carbohydrates to stimulate fecal bifidobacteria in healthy humans: a double-blind, randomized, placebo-controlled, parallel-group, dose-response relation study. (Bouhnik 2004)PubMed
- Dietary fructooligosaccharides affect intestinal barrier function in healthy men. (Ten Bruggencate 2006)PubMed
Related ingredients
Probiotic Blend (Multi-Strain)
ProbioticA generic placeholder for a multi-strain probiotic blend, typically combining several Lactobacillus and Bifidobacterium species and sometimes Streptococcus thermophilus or a Bacillus spore.
Typical: 10–50 B CFU
Magnesium Oxide
MineralThe most concentrated magnesium source at about 60% elemental magnesium, which is why it dominates in multivitamins and small tablets.
Typical: 200–350 mg
Inulin (Chicory Root Fiber)
PrebioticInulin is a soluble, fermentable fructan fiber extracted mainly from chicory root, though it also occurs in Jerusalem artichoke, agave, and onions.
Typical: 5–10 g
Piperine (Black Pepper Extract 95%)
BotanicalThe pungent alkaloid isolated from black pepper fruit, used in tiny amounts to raise the absorption of other ingredients rather than for its own effects.
Typical: 5–20 mg
Greens Blend (Generic)
OtherA generic greens blend is a placeholder for the dried plant powders typical of greens products: cereal grasses such as wheatgrass and barley grass, spirulina and chlorella, leafy vegetables like spinach and kale, and often fruit or vegetable extracts.
Typical: 3–10 g