What Is Formula?

Breast milk is magic, but its stand-in is pretty impressive too

There is no question that when it comes to breast milk vs. formula, that we advocate for breastfeeding when possible, for as long as it makes sense for your family. That said, with all of the pressure moms are under, the challenges of being a working mom and the endless scenarios that could impact your breastfeeding relationship no matter where you are in the journey, it’s important to understand alternative options.

Maybe your freezer breaks down and you lose your stash. Maybe your supply takes a hit while you battle mastitis, or you simply have a crazy week that doesn’t allow for enough pumping sessions. Or, maybe you’ve exclusively breastfed for nine-months and now your supply is dwindling and it’s time to introduce a supplement. Formula can be a solution to fill that gap (and relieve some stress!) when you need it.

While we all know the benefits of breast milk, formula is a wonderful, modern invention helps ensure all babies are fed and happy, and that’s the most important thing. Here are a few answers to those pressing questions.

What is formula? What’s in it?

Formula is mainly a combination of protein, fat and carbohydrates. It also provides important nutrients and often includes beneficial additives like iron, DHA and probiotics. There are three major types approved by the FDA: cow’s milk-based formula, soy-based formula and protein hydrolysate formula. Specialized prescription formulas are also available for premature babies and infants with specific medical conditions.

Why can’t we give babies cow’s milk or soy milk? How is formula different?

Formula was created to resemble a mother’s breast milk as much as possible, though includes some significant alterations. Cow’s milk-based formula contains more lactose than cow’s milk, plus more easily digestible fats in the form of vegetable oils. High concentrates of proteins and certain minerals that can overwork baby’s immature kidneys are removed from cow’s milk when it’s made into formula, and more iron, vitamin C and other nutrients are added. Soy-based formula has the same nutrients added, but it doesn’t contain lactose, making it a great fit for babies with dairy allergies. Protein hydrolysate formulas contain a protein that’s been broken down (hydrolyzed) into a smaller size than in cow’s milk and soy-based formulas, making them gentler on the tummies of babies with extra sensitivities, including protein allergies.

What’s the difference between ready-to-feed, liquid concentrate, and powder formula?

Ready-to-feed formula comes in a liquid form and you don’t have to add any water. Just pour it into a bottle and feed. A liquid concentrate or powder formula must be diluted with the appropriate amount of water before feeding. Sometimes, the ready-to-feed and powder versions of the same formula will have slightly different ratios of ingredients, but all the necessary and important ones are present in both types. It’s truly up to your personal preference (and your baby’s), as well as your budget and what works best for your lifestyle.

How do I mix it? Can I use tap water?

If your tap water supply is clean, it’s okay to use for preparing formula. If you have concerns about water purity, check with your pediatrician and your water department. You could also choose to use filtered water, bottled water, or nursery water, which have various levels of fluoride added in. The optimal fluoride levels in the water you mix into your formula depend on how often you’re using it: see the CDC’s guidelines here. The most important part of preparing formula is to follow the directions on the container, which provide the appropriate ratio of water to formula.

Choosing a formula

There are endless formula options and choosing the right one will depend on your baby’s needs and your lifestyle. Even if you plan to only breastfeed, mastitis, broken freezers, lost luggage, etc. might happen. Talk to your doctor or your lactation counselor about what to look for if you find yourself in need of a supplement. Once you choose a brand, stick with it, so you don’t throw off your baby’s digestion.


The best feeding routine is one that keeps your baby full and healthy. Any amount of breast milk you provide is an amazing gift, and sometimes, despite our best efforts and intentions, we need some help. Breastfeeding is a commitment and should be taken seriously. If you want breast milk to factor into your feeding plan for your baby, you have options: Ashland Health can help get you the right breast pump for your needs, connect you with an IBCLC, and more. Contact us today.