Compare Supplements

Side-by-side comparison of 2 supplements

Fos4.5

Fructooligosaccharides

High safety

Gos5.0

Galactooligosaccharides

High safety

Evidence

Likely helps

Evidence Score4.5/10

Studies: 11

Meta-analyses: 3

Probably helps

Evidence Score5/10

Studies: 10

Meta-analyses: 2

Dosage & timing

Dosage:

5-10 g/day. The meta-analysis found larger bifidogenic effects above 5 g/d, and the dose-finding study concluded 10 g/d was the optimal well-tolerated dose. Do not extrapolate upward: at 20 g/d excess flatus became significantly more frequent and more intense

Best Time:

With meals · with food

Take with food

Form:

Short-chain FOS (scFOS) powder

Dosage:

3.5-5.5 g/day. Going higher is not supported: in the one IBS trial, 3.5 g/d improved more symptoms than 7 g/d, and in stressed students 2.5 g lowered cold-or-flu symptom scores across all stress levels while 5 g helped only at lower stress

Best Time:

With meals · with food

Take with food

Form:

Trans-galactooligosaccharide (B-GOS) powder, the form used in the trials

What you'll notice

📈 Higher faecal bifidobacteriapositive

1-2 weeks

🩸 Lower homocysteinepositive

4 weeks

🚫 No glycaemic benefit where inulin had onenegative

n/a

📈 Higher faecal bifidobacteriapositive

1-2 weeks

💚 Fewer stress-related GI symptomspositive

8 weeks

🚫 No global symptom response in IBSnegative

n/a

Safety

High safety

Contraindications:

Strict low-FODMAP diet — FOS is one of the oligosaccharides that diet removes
Hereditary fructose intolerance

Drug Interactions:

Lactulose (and other fermentable laxatives)

Side Effects:

Excess flatusBloatingAbdominal distension, rumbling and pain

High safety

Contraindications:

Strict low-FODMAP diet — GOS is one of the oligosaccharides that diet removes
Active symptom flare in FODMAP-sensitive IBS

Drug Interactions:

Lactulose (and other fermentable laxatives)

Side Effects:

Flatulence and bloatingAbdominal discomfort or altered stool consistency

Works well with

Inulin

complementary

Galactooligosaccharides (GOS)

complementary

Probiotics

enhances

Fructooligosaccharides (FOS)

complementary

Inulin

complementary

Probiotics

enhances

How they work together

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