When the crying will not stop, the gut is one of the first places to look.
NurtureBio is a daily synbiotic for babies and toddlers, formulated with four infant-friendly probiotic strains and five human milk oligosaccharides. Made to support a balanced gut microbiome during the colic window and the months that follow.
Formulated with pediatric microbiome researchers · Third-party tested · Made for ages 0 to 48 months
What colic actually is, and where the gut fits in
Colic is the term pediatricians use when an otherwise healthy baby cries for more than three hours a day, more than three days a week, for more than three weeks. It usually starts in the first few weeks of life, peaks around six weeks, and resolves by three or four months. No one knows the single cause. The current science points to a combination of an immature gut, an immature nervous system, and a microbiome that is still under construction.
That last piece is where research has moved the most in the past decade. The gut microbiome of colicky infants tends to look different from that of non-colicky infants. Researchers have spent significant time studying the species Limosilactobacillus reuteri in this context, particularly in breastfed babies, and the broader role of the gut microbiome in infant comfort and digestion is now part of mainstream pediatric conversation.
What is actually in the sachet
Four infant-friendly probiotic strains and five human milk oligosaccharides, in one daily synbiotic.
The probiotic side of the blend
These are the kinds of bacteria commonly found in the guts of breastfed babies, selected for their relevance to early-life gut health.
- B. infantis A foundational bifidobacterium that thrives on HMOs and is closely associated with the infant gut.
- B. bifidum Two well-studied bifidobacteria strains that support gut balance during early life.
- L. reuteri One of the most studied probiotic species in infants, including for crying and fussiness research.
The prebiotic side of the blend
HMOs are the prebiotic carbohydrates naturally abundant in breast milk. They feed the beneficial bacteria in the baby's gut.
- 2'-Fucosyllactose The most abundant HMO in breast milk for most mothers.
- Difucosyllactose A fucosylated HMO that supports a breast-milk-like gut environment.
- Lacto-N-tetraose A core HMO involved in early microbiome shaping.
- 3'-Sialyllactose A sialylated HMO involved in gut and brain development.
- 6'-Sialyllactose A sialylated HMO that helps nourish beneficial bacteria.
Curious about the specific strains? See our full formulation page
Why a synbiotic makes sense for the colic window
Probiotics introduce beneficial bacteria
Four infant-friendly strains, including L. reuteri, which has been widely studied in infants.
HMOs feed the bacteria that matter
Five human milk oligosaccharides modeled after the prebiotics naturally abundant in breast milk.
Together they support a balanced gut environment
Which is part of what the body uses to support comfortable digestion during a noisy developmental window.
A daily sachet, made for the first four years.
Mixes into breast milk, formula, water, or soft food.
Shop NurtureBioMade for the colic window and the months that follow
NurtureBio is formulated for babies and toddlers ages 0 to 48 months. Many parents start during the colic window itself, when daily fussiness is at its peak. Others begin after the worst of it has passed, as part of a daily routine that supports gut health from the start.
It mixes easily into breast milk, formula, water, or soft foods, depending on your baby's age and what works for your day.
Why parents trust NurtureBio
Built with the researchers who study this
Our Scientific Advisory Board includes Dr. Jim Versalovic, Dr. Ardythe Morrow, Dr. David Newburg, and Dr. Diana Taft. They are among the most cited researchers in human milk and infant microbiome science.
Active research at the University of Cincinnati
We are conducting clinical research at the University of Cincinnati College of Medicine to advance the science of breast milk and infant gut health.
Built by parents who lived this
NurtureBio was started by Stuart and Christina Smith after their son fell from the 30th to the 6th growth percentile and went through five rounds of antibiotics in five months. They could not find a product that took the infant gut microbiome seriously, so they built one with help from leading researchers in the field.
A daily synbiotic, one sachet at a time
NurtureBio Infant and Toddler Synbiotic
30 sachets. One per day. Mixes into breast milk, formula, water, or soft food.
Free shipping on subscriptions Third-party tested Made in France
Common questions from parents
Can probiotics help with my baby's colic?
The research on probiotics and infant colic has focused most heavily on the species Limosilactobacillus reuteri, particularly in breastfed babies. NurtureBio is a daily synbiotic that includes L. reuteri along with three other infant-friendly strains and five human milk oligosaccharides. It is not a treatment for colic, and it is not a substitute for medical care. Many families use it as part of a daily routine that supports gut health during the early months and beyond.
What is colic, exactly?
Colic is generally defined as a healthy baby crying for more than three hours a day, more than three days a week, for more than three weeks. It usually starts in the first few weeks of life and resolves by three or four months. The cause is not fully understood, but research points to a combination of gut, nervous system, and microbiome factors.
When does colic usually start and end?
Colic typically begins around two weeks of age, peaks around six weeks, and resolves on its own by three or four months. It can feel much longer than that when you are in the middle of it.
What is the difference between colic and normal crying?
All babies cry. Colic is the term used when crying is significantly more intense, more prolonged, and harder to soothe than typical infant fussiness. The "rule of threes" is the most common clinical definition pediatricians use.
Is colic a sign of something serious?
In most cases, no. Colic is considered a developmental phase, not a medical condition. That said, persistent crying can occasionally be a sign of something that needs medical attention. If your baby has fever, vomiting, poor feeding, blood in the stool, or a sudden change in behavior, call your pediatrician.
How is NurtureBio different from gripe water or gas drops?
Gripe water and gas drops are short-term remedies aimed at easing immediate discomfort. NurtureBio is a daily synbiotic formulated to support the gut microbiome itself, with probiotics and human milk oligosaccharides modeled after breast milk. They are different categories of product.
How do I give NurtureBio to a young baby?
One sachet per day, mixed into a small amount of breast milk or formula. For older babies on solids, it can also be mixed into water or soft food. Follow the directions on the package.
How long until I notice anything?
Every baby is different, and colic itself follows a developmental curve that often improves on its own around three to four months. Gut health products generally work best with consistent daily use over time. NurtureBio is built as ongoing daily support, not as a quick fix.
Is it safe to give with breast milk and formula?
Yes. NurtureBio is formulated to mix into either, and it is also fine in water or soft food once your baby is on solids. Always follow the directions on the package.
Can I use NurtureBio while my baby is on antibiotics?
Many families do use NurtureBio during and after a course of antibiotics as part of a daily gut support routine. If your baby is on a specific medication, check with your pediatrician.
What ages is NurtureBio for?
NurtureBio is formulated for babies and toddlers ages 0 to 48 months.
When should I call my pediatrician?
Call your pediatrician if your baby's crying is accompanied by fever, vomiting, poor feeding, blood in the stool, a sudden behavior change, or signs of dehydration. NurtureBio supports daily gut health and is not a substitute for medical care.
Support your baby's gut through the loudest months and beyond.
A daily synbiotic for babies and toddlers, made with the ingredients their gut is biologically wired to use.
Shop NurtureBio