Supplement Formulator
Log inStart formulating

Galactooligosaccharides (GOS)

Prebioticgalactan fiberModerate dose evidence

Also known as: GOS, galacto-oligosaccharides, trans-galactooligosaccharides, TOS, Bimuno, Vivinal GOS

Add to a formula

Galactooligosaccharides are chains of galactose units produced enzymatically from lactose, which makes them structurally similar to some of the oligosaccharides in human milk. They are the standard prebiotic in infant formula and are used in adult gut-health, synbiotic, and stress-support products. Randomized trials in healthy adults have shown increases in fecal bifidobacteria at a few grams per day, and GOS is generally better tolerated than FOS at equal doses. Because the starting material is lactose from dairy, finished GOS may carry trace milk protein and residual lactose.

Research summary

Selectively fermented by bifidobacteria via beta-galactosidase activity; studied for effects on microbiota composition, stool consistency, and immune markers.

Gut & digestionImmune

Dosage

Daily amounts, of compound.

Lowest studiedTypical rangeHighest studiedUpper limit
2.5 g2.5–5 g——

Take 2.5–5 g daily with a meal; tolerance is generally good at this level. Commercial GOS powders and syrups are usually 50–70% GOS on a dry basis with the remainder lactose, glucose, and galactose, so check the CoA and dose by GOS content rather than total powder weight.

Standardization: GOS content stated on dry basis (commonly 50–90%); residual lactose declared

Source material: enzymatic conversion of lactose (dairy-derived)

As supplied: Purity varies widely (about 50–90% GOS); raw-material weight must be scaled to the assayed GOS percentage.

Format suitability

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

Mildly sweet, very soluble; available as powder or syrup. Syrup grades are not suitable for capsules.

Formulation notes

Dairy-derived; may contain trace milk protein and residual lactose, so declare milk as an allergen unless the supplier certifies otherwise. Hygroscopic.

  • Allergen: milk

Sources

  1. Prebiotic evaluation of a novel galactooligosaccharide mixture produced by the enzymatic activity of Bifidobacterium bifidum NCIMB 41171, in healthy humans: a randomized, double-blind, crossover, placebo-controlled intervention study. (Depeint 2008)PubMed
  2. 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

Related ingredients