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Xylooligosaccharides (XOS)

Prebioticxylan fiberModerate dose evidence

Also known as: XOS, xylo-oligosaccharides, PreticX, corn cob oligosaccharides

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Xylooligosaccharides are short chains of xylose produced by enzymatic breakdown of xylan from corn cobs or other plant cell walls. They are notable for acting at much lower doses than inulin or FOS: randomized trials in healthy adults have reported increases in fecal bifidobacteria at roughly 1–3 g per day, with little gas or bloating. That potency lets formulators fit an effective prebiotic dose into capsules, tablets, or gummies where gram-level fibers will not work. XOS is used in synbiotic capsules, gut-health gummies, and compact daily formulas.

Research summary

Selectively fermented by bifidobacteria via xylanase and xylosidase activity; studied for effects on microbiota composition and immune markers at low gram doses.

Gut & digestionImmune

Dosage

Daily amounts, of compound.

Lowest studiedTypical rangeHighest studiedUpper limit
—1,000–2,000 mg——

Take 1–2 g daily with a meal; tolerance is good at this level because the total fermentable load is small. Effects in trials developed over four to eight weeks. Commercial XOS ranges from about 35% to 95% purity, so dose by assayed XOS content.

Standardization: XOS content stated on dry basis (commonly 35%, 70%, or 95% grades)

Source material: corn cob xylan, enzymatically hydrolyzed

As supplied: Grades vary (35–95% XOS); scale raw-material weight to the assayed XOS percentage.

Format suitability

  • Capsule
  • Powder
  • Tablet
  • Softgel
  • Gummy
  • Liquid

Mildly sweet, soluble, and low-dose enough for capsules, tablets, and gummies.

Formulation notes

Hygroscopic; use desiccant when co-encapsulated with probiotics. PreticX is a branded XOS; generic material is widely available.

Sources

  1. Xylooligosaccharide increases bifidobacteria but not lactobacilli in human gut microbiota. (Finegold 2014)PubMed
  2. Xylo-oligosaccharides alone or in synbiotic combination with Bifidobacterium animalis subsp. lactis induce bifidogenesis and modulate markers of immune function in healthy adults: a double-blind, placebo-controlled, randomised, factorial cross-over study. (Childs 2014)PubMed
  3. Xylo-oligosaccharide (XOS) in combination with inulin modulates both the intestinal environment and immune status in healthy subjects, while XOS alone only shows prebiotic properties. (Lecerf 2012)PubMed

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