The scGOS/lcFOS Blend: How Prebiotics Support the Baby's Gut
Some infant formulas include a specific combination of short- and long-chain oligosaccharides. Here's what that blend is, and why it's built the way it is.
A blend designed with purpose
Prebiotics are nutrients that feed the beneficial bacteria living in a baby's gut, and they're linked to a range of health benefits. scGOS/lcFOS, used in a 9:1 ratio, is one of the prebiotic blends found in infant formula.
It combines short-chain galacto-oligosaccharides (90%) with long-chain fructo-oligosaccharides (10%), inspired by the range of oligosaccharide sizes found in nature.
Why chain length matters
Oligosaccharides differ in how many sugar units they're built from — their degree of polymerisation. According to a 2025 systematic review, scGOS chains span 2 to 8 units, while lcFOS chains run past 23. Together, they cover a broad, diverse structure.
That diversity matters because different chain lengths behave differently once they reach the gut. Shorter chains tend to ferment quickly, while longer ones break down more slowly and can stay active further along the colon. Combining both gives beneficial bacteria a steady supply of fuel across a wider stretch of the gut.
"
scGOS/lcFOS 9:1 is one of the most extensively studied prebiotic blends used in infant formula.
— Summary of the scientific evidence on prebiotic blends in infant formula
What the clinical evidence shows
A 2025 systematic review and meta-analysis pooled 18 publications covering 1,675 infants and toddlers, with 11 of those studies included in the meta-analysis itself. Formula supplemented with scGOS/lcFOS 9:1 was consistently associated with higher levels of bifidobacteria, softer and more frequent stools, lower stool pH, higher faecal acetate and lactate concentrations, and higher faecal secretory IgA levels — all markers linked to a healthier gut environment.
The blend has also been shown to be well tolerated in healthy term infants, with clinical studies consistently reporting normal growth patterns, including appropriate weight gain, linear growth, and head circumference growth.
A well-established regulatory background
European Regulation (EU) 2016/127 specifically references the combination of 90% oligogalactosyl-lactose and 10% high-molecular-weight oligofructosyl-saccharose for use in infant formula, up to 0.8 g per 100 mL.
Conclusion
scGOS/lcFOS 9:1 combines complementary short- and long-chain oligosaccharides for a broader fermentation profile in the gut. It is backed by a substantial body of clinical evidence and a well-established regulatory foundation under EU law.
