Breastmilk is amazing, but it’s not always an option for every family. Whether due to low milk supply, postpartum difficulties, adoption, or personal preference, many families turn to infant formula as an excellent way to nourish their babies.
The good news? Infant formula is carefully regulated by the FDA to provide babies with essential nutrients to thrive. It’s a safe, trusted option that supports your baby’s development [1]. In this guide, we’ll walk you through the basics of formula feeding and share tips to help you feel confident in caring for your baby. Let’s get started.
Understanding formula types and forms
Infant formulas are designed to closely mimic breastmilk, but they cannot replicate how breastmilk naturally adapts to meet a baby's changing nutritional needs from newborn to toddlerhood [1]. Breastmilk dynamically adjusts its fat, protein, and immune-boosting components based on the baby’s age, health, and feeding patterns. In a similar way, parents can adjust formula types to align with their baby’s changing needs, providing the best possible nutrition as their child grows.
The main formula types include:
- Cow’s Milk Formula – Suitable for most babies, these formulas contain proteins from cow’s milk modified to be digestible for babies.
- Soy-Based Formula – Often chosen by families following plant-based diets or those with babies who have lactase deficiency or galactosemia.
- Specialized Formulas – Designed for babies with specific health needs, these can include hydrolyzed proteins for easier digestion or hypoallergenic options.
Formulas also come in three convenient forms:
- Ready-to-feed (just pour and serve)
- Concentrated liquid (mix with water), and
- Powdered (measure and shake with water).
Ready-to-feed formulas are the most convenient, while powder options are often the most budget-friendly and environmentally sustainable.
Adapting formula to your baby’s changing needs
While all infant formulas aim to provide complete nutrition, there is no universal "best formula" for every baby. Just as breastmilk naturally adjusts its composition to meet a baby's evolving needs, your baby may benefit from a change in formula as they grow.
Newborns often thrive on standard cow’s milk or hydrolyzed formulas, but as babies reach different developmental milestones, their nutritional needs shift. Some formulas are designed specifically for preemies or younger infants, while others cater to older babies who are beginning to eat solids and need complementary nutrients. For example, formulas for infants under six months often focus on gentle digestion and immune support, while formulas for older babies may include additional iron, DHA, and prebiotics to support brain development and a maturing gut microbiome [2].
Beyond age, other factors—such as digestive comfort, changes in appetite, or emerging food sensitivities—may indicate it’s time to adjust formulas. If your baby experiences persistent gas, reflux, or fussiness, switching to a partially hydrolyzed or probiotic-enriched formula may help. Some families give their child a toddler formula after infancy. Experts debate if they’re necessary, though—so you should consult your pediatrician.
The best formula choice depends on your baby’s individual needs at any given stage. As your little one grows, factors like digestion, nutrient absorption, and immune support may influence which formula works best. In the next sections, we’ll explore important considerations—such as fortification, hydrolyzed proteins, and probiotic-enriched formulas—to help you make informed decisions about your baby’s nutrition.
Key nutrients in formula [3]
- Carbohydrates – Lactose, the main carbohydrate in breastmilk, is usually found in infant formulas. However, lactose-free formulas may include alternatives like sucrose or corn syrup solids for babies with lactose intolerance.
- Proteins – Proteins in formula are essential for growth and development. Cow’s milk protein formulas are common, while soy proteins serve as an alternative. Specialized options also include hydrolyzed proteins, broken down for easier digestion in babies with sensitivities.
- Fats – Often sourced from vegetable oils, fats in formula provide necessary energy. Some formulas also include omega-3 and omega-6 fatty acids like DHA and ARA, supporting brain and eye development.
Extras: HMOs, prebiotics, and probiotics
Some formulas now contain human milk oligosaccharides (HMOs), which are unique sugars naturally found in breastmilk and beneficial for immune and gut health. Among these, 2’-fucosyllactose (2’-FL) is one of the most abundant and studied types of HMO.
Research has shown that formulas with 2'-FL can significantly reduce inflammatory markers in formula-fed babies, bringing their immune profiles closer to those of breastfed infants [4]. This suggests that HMO-supplemented formulas may help support immune resilience and offer benefits that mimic the immune-boosting qualities of breastmilk.
HMOs also act as prebiotics, providing food for beneficial gut bacteria like Bifidobacterium [5], which can help prevent harmful bacteria from taking hold and promote a balanced gut microbiome [6].
Other HMOs, such as lacto-N-neotetraose (LNnT), are being studied for their potential to boost immune health and support brain development [7]. While the range of HMOs in formula isn’t as extensive as breastmilk’s, incorporating HMOs, especially 2’-FL, brings formulas closer to breastmilk's natural composition. This supports babies in building a healthy gut and immune system early on.
In addition to HMOs, many formulas include probiotics (beneficial bacteria) and prebiotics (fiber that feeds these bacteria), such as galactooligosaccharides (GOS) and fructooligosaccharides (FOS). These ingredients can help infants develop a balanced microbiome, similar to breastfed babies [8]. The best way to get insight into your baby’s microbiome balance is by taking a Baby Gut Health Test, which will also identify if your baby could benefit from specific probiotic or HMO supplements.
Choosing the right infant formula
Selecting a formula can feel overwhelming with so many options available. Focusing on your baby’s health needs and understanding labels can simplify your decision. Here are a few steps to help you make an informed choice:
Check for FDA regulation
The U.S. FDA regulates all infant formulas to ensure they meet strict nutrition standards. Look for added ingredients that might be beneficial, like DHA, ARA, and HMOs, and try to avoid added ingredients your baby doesn’t, such as certain oils or added sugars.
Review the nutritional composition
Choose a formula with a whey-to-casein ratio that resembles breastmilk (ideally higher in whey), as whey protein is easier on a baby’s stomach [9]. For sensitive tummies, partially-hydrolyzed or fully-hydrolyzed protein formulas break down proteins for easier digestion.
While lactose is generally the preferred carbohydrate due to its health benefits [1], formulas with alternatives like sucrose or corn syrup can be suitable if true lactose intolerance is diagnosed. However, switching to lactose-free products without a clear medical need may lead to unnecessary dietary changes.
Consider added nutrients
Look for formulas fortified with key nutrients, especially if breastfeeding is not an option. Vitamin D, iron, and omega fatty acids (DHA and ARA) support brain, eye, and bone development, while probiotics and prebiotics aid digestive health [10-12]. Formulas containing HMOs, like 2’-fucosyllactose (2’-FL), also support a baby’s immune system and gut health, offering benefits similar to breastmilk’s natural sugars [13].
Identify special considerations
If your baby has allergies or intolerances, specialized formula options are best. Babies with a cow’s milk protein allergy may need an extensively hydrolyzed or amino acid-based formula, which removes the proteins most likely to cause reactions. Babies with galactosemia or lactose intolerance can benefit from soy-based or lactose-free formulas, respectively [14]. In these cases it is best to follow the recommendations of your health practitioner.
Consult your pediatrician
Ultimately, your baby’s health practitioner can be a helpful resource for choosing a formula that fits their dietary and health needs. They can help ensure you’re on the right track, even if you’re considering specific formulas or additives.
Tips for formula preparation and storage
- Preparation – Use clean water and follow the manufacturer’s instructions closely. Avoid over- or under-diluting formulas, as both can affect nutritional quality [15].
- Storage – Prepared formula can be stored in the fridge but should be discarded after 24-48 hours, depending on the type. Never warm formula in a microwave, as this can create hot spots [16].
- Watch for Recalls and Expiration Dates – Regularly check expiration dates and stay updated on any formula recalls to ensure your baby’s formula is safe.
Finding what works for your family
Feeding your baby is a personal decision, and every family’s journey is unique. Whether you choose breastfeeding, formula-feeding, or a combination, what matters most is ensuring your baby receives the nutrients they need to thrive.
Modern formulas are carefully crafted to provide essential nutrients like carbohydrates, proteins, and fats while supporting brain, eye, and immune health with added ingredients like DHA, ARA, and HMOs. Explore options based on your baby’s health, comfort, and digestion. If you’re unsure, your pediatrician is a valuable resource to guide you in finding the best fit for your little one.
At the heart of it all, your love and care make the biggest difference. You’re giving your baby the best start, no matter the feeding path you choose.
