Most standard infant formulas do not contain probiotics. The majority of formulas on the market are made without live bacteria, though a small number of specialty products do include specific probiotic strains. If you’re looking for a formula with probiotics, you’ll need to read labels carefully, because it’s far from the default.
Which Formulas Contain Probiotics
Only a handful of infant formulas sold in the U.S. include probiotics. Nutramigen with Probiotic LGG, a hypoallergenic formula, is one well-known example listed among formulas marketed in the U.S. through the FDA. Some other brands offer probiotic-containing lines, but they represent a small slice of the overall formula market. The vast majority of standard, sensitive, and organic formulas contain no live bacteria at all.
The strains you’re most likely to encounter in probiotic formulas include Bifidobacterium lactis BB-12, Lactobacillus rhamnosus GG, and Lactobacillus reuteri DSM 17938. Each of these has been studied in infants and selected for its ability to survive the acidic environment of the stomach. When a formula does include probiotics, the label will list the specific strain name along with the number of live organisms, typically expressed in CFU (colony-forming units).
What Probiotics Actually Do in Formula
The goal of adding probiotics to formula is to nudge a baby’s gut bacteria closer to what you’d see in a breastfed infant. Breast milk naturally contains beneficial bacteria and feeds them with specialized sugars, creating a gut environment rich in helpful microbes. Formula-fed babies tend to develop a different bacterial profile, with fewer beneficial species and more of certain less desirable ones.
Formula enriched with Bifidobacterium animalis has been shown to shift gut bacteria patterns, stool pH, and levels of a key immune protein (fecal IgA) to more closely resemble those of breastfed infants. Bifidobacterium lactis BB-12 increases the abundance of beneficial bacteria while lowering counts of less favorable species like Enterobacteriaceae and Clostridium. Lactobacillus rhamnosus GG supplementation reduces the proportion of a type of bacteria linked to gut imbalance.
Evidence on Colic and Crying
The strongest evidence for probiotics in early life involves colic. A meta-analysis found that probiotics significantly reduce excessive crying, the hallmark symptom of infantile colic, likely through anti-inflammatory effects in the gut. Multiple clinical trials back this up with consistent results.
In one study, Lactobacillus reuteri DSM 17938 given to colicky infants for 21 days produced a 100% treatment success rate, with significant reductions in mean crying time and improvements in maternal depression scores. Another trial using the same strain over 30 days found significantly shorter crying times, increased levels of beneficial Lactobacillus bacteria, and reduced markers of gut inflammation. A 90-day study using two Bifidobacterium breve strains in both breastfed and formula-fed infants also showed a significant drop in crying time.
It’s worth noting that most of these colic trials used probiotic supplements added to feeds rather than probiotic-containing formula specifically. The bacteria are the same, but the delivery method differs.
Prebiotics Are More Common Than Probiotics
If you’ve been scanning formula labels, you’ve probably noticed ingredients like GOS, FOS, or 2′-FL more often than any probiotic strain. These are prebiotics, not probiotics, and the distinction matters. Probiotics are live bacteria. Prebiotics are specialized fibers and sugars that feed beneficial bacteria already in your baby’s gut.
Breast milk is naturally rich in human milk oligosaccharides (HMOs), complex sugars with over 200 identified types. HMOs act as prebiotics with strong effects on promoting the growth of Bifidobacterium species. For years, it was impossible to synthesize HMOs, so formula makers used alternatives like galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS), inulin, and polydextrose. Today, several synthetic HMOs like 2′-FL and LNnT are added to many mainstream formulas.
Prebiotics show up in far more formulas than probiotics do. So when a formula is marketed as supporting digestive health or gut development, it’s often relying on prebiotics rather than live bacteria. Check the ingredient list to know which you’re getting.
How to Read the Label
If a formula contains probiotics, the label will typically list the full strain name, including the genus, species, and an alphanumeric strain code. For example, you might see “Lactobacillus reuteri DSM 17938” or “Bifidobacterium lactis BB-12.” The label should also state the number of viable organisms, usually something like “1 x 10⁸ CFU.” If you don’t see a specific bacterial strain and a CFU count on the packaging or ingredient list, the formula doesn’t contain probiotics.
Don’t confuse prebiotics on the label with probiotics. Ingredients like “galacto-oligosaccharides,” “2′-fucosyllactose,” or “fructo-oligosaccharides” are prebiotics. They’re fiber-like compounds, not live organisms.
Safety Considerations
For healthy, full-term infants, the probiotic strains used in commercial formula have a solid safety track record. These strains go through evaluation before they can be added to formula products.
The picture is very different for premature or medically fragile infants. The FDA has raised specific concerns about probiotic products used in hospitalized preterm babies, warning that these infants are at risk of invasive, potentially fatal infections caused by the very bacteria or yeast in the probiotics. The agency reported that probiotic products contributed to serious illness, including one infant death in 2023 and more than two dozen adverse events since 2018. These cases involved probiotic supplements used in hospital settings rather than commercial formula, but the underlying concern applies: live organisms carry real risk for babies with immature immune systems.
Many GRAS (Generally Recognized as Safe) notices for probiotic strains explicitly exclude infant formula from their approved uses. The FDA has urged that high-quality clinical trials be conducted before these products are used broadly in vulnerable infants. For preterm babies, any probiotic use should be a conversation with the medical team overseeing their care, not a decision made from the formula aisle.