HOME › FORMULAS › INGREDIENTS › GALACTOOLIGOSACCHARIDES (GOS)
Galactooligosaccharides (GOS)
A prebiotic fibre made from milk sugar. It is in one of our formulas, Digestion & microbiome, and it carries no authorised EU health claim, because EFSA assessed the ones made for it and rejected them.
WHAT WE ARE ALLOWED TO SAY
No authorised claim. EFSA rejected them.
EFSA assessed claims for GOS on digestive discomfort, on pathogens and on a bifidogenic effect, and none of them made it onto the EU register. Later applications for a branded GOS, Bimuno, were turned down too, in 2011 and 2014. So there is no wording to quote here, and we are not going to write a sentence that sounds like one.EFSA assessed claims for GOS on digestive discomfort, on pathogens and on a bifidogenic effect. None of them made it onto the EU register.
In Digestion & microbiome, the one authorised claim on the page belongs to zinc, not to the fibres. The inulin next to it does have an authorised claim on bowel function, but only at 12 g a day, and the formula carries 3 g. GOS is there as a second prebiotic fibre, not as the source of any claim.
WHAT IT IS
No form to choose. One thing to know about where it comes from.
GOS is a short chain of sugars that you do not digest. It reaches the colon intact, where bifidobacteria and lactobacilli ferment it into short-chain fatty acids such as acetate, propionate and butyrate. Our file records no chemical forms to choose between, so the form is not a claim argument. What does matter is the origin: it is made from milk sugar, and that goes on the label.
A non-digestible oligosaccharide, fermented in the colon rather than absorbed. Our file records it leaving the body through the gut, with no oral bioavailability to measure.
Our file records it as made enzymatically from bovine lactose, with possible dairy residues and residual lactose. Milk is a declared allergen, and residual lactose rules it out with galactosaemia.
Our file puts the onset at one to two weeks. That fits a base formula held for eight weeks, not a dose you would expect to feel the same morning.
Our file has the mechanism and the origin, but no supplier grade, purity or lactose content on record yet. Until it does, treat the GOS in our formula as milk-derived, and read the allergen on the label if you are allergic to milk or cannot take lactose.No supplier grade or lactose content is on record yet. Until it is, treat it as milk-derived and read the allergen on the label.
WHERE IT APPEARS
One of the twenty-nine carries GOS.
It sits in Digestion & microbiome, next to inulin, three bacterial strains and zinc, taken before breakfast. The adult trials named in our file used 2.5 – 10 g a day, so at 2,000 mg this formula sits below that range, and we would rather tell you that than leave it out.
THE CEILING
No upper limit has been set.
EFSA has not set a tolerable upper intake level for GOS, so there is no ceiling to draw here. What our file does record is where discomfort starts: above 15 g a day, GOS causes wind and bloating. At 2,000 mg you are well under that, but GOS is not the only fermentable fibre in the formula, so the amounts are added up rather than counted apart.EFSA has not set an upper intake level for GOS. Our file records wind and bloating above 15 g a day, and the fibres in the formula are added up.
Our inulin file lists GOS among the fermentable fibres at risk of doubling up, so the engine counts them together: 5 g in Digestion & microbiome. The fermentable-fibre totals our files give range from 8 – 10 to 10 – 15 g a day. No other VION formula carries GOS today.
The formula is reviewed at 8 weeks. If bloating or wind persists, the GOS dose is reviewed. If SIBO is diagnosed, the formula comes out.
Galactosaemia, because it contains residual lactose. Milk allergy, as it is made from bovine lactose, and care with lactose intolerance, as traces of lactose are possible. A low-FODMAP diet, which removes GOS. With IBS or FODMAP sensitivity, introduce it gradually, as some wind is possible at first. The formula that carries it is not for SIBO or severe immunosuppression. And the usual three: do not exceed the daily dose, it does not replace a varied and balanced diet, and keep it out of reach of young children.
WHAT IT REACTS WITH
No documented pairs yet. One overlap, one allergen.
GOS is one of the 140 ingredients in our library, so it has 139 possible partners. None of them is among the 443 pairs we have documented so far. What we do have is an overlap flagged in another ingredient's file, and an allergen on its label.
Not an entry in our interaction table, but our inulin file lists GOS among the fermentable fibres whose amounts have to be added together. In Digestion & microbiome that is 3 g of inulin plus 2 g of GOS.
Our file records GOS as made from bovine lactose, with possible dairy residues. Milk, including lactose, must be declared as an allergen under Regulation (EU) 1169/2011, Annex II.
No pair with another ingredient or with a medicine is documented for GOS, and our pharmacokinetic file found nothing on liver enzymes. That is an open question, not a clean result.
443 of the 9,730 possible pairs in our library are documented, which is 4.55%, and none of them involves GOS. The rest are not "safe", they are simply unchecked, and we would rather write that down than let the number look like a badge.443 of the 9,730 possible pairs in our library are documented, which is 4.55%, and none of them involves GOS. The rest are not safe, they are simply unchecked.
SOURCES
Everything on this page, with its reference.
Reviewed by VION nutrition team · last reviewed 16 September 2026
140 INGREDIENTS · 64 IN USE TODAY
Every one of them has a page like this.
What it is, what we are allowed to say about it, which formulas carry it, what it reacts with and where each of those statements comes from. No proprietary blends, no hidden amounts.