Often new parents are nervous about mixing and matching infant formula they offer their babies. They worry if they switch from one formula brand to another, they may cause their baby fussiness, stool changes, upset or worse–that they could put their baby at risk.

It’s safe to mix and match infant formulas if you are following standard mixing instructions. Really.

Although spitting up or gassiness is usually not due to the protein in formula (cow’s milk versus soy versus hypoallergenic), sometimes changing formula helps new babies and their parents who worry. Switching them up can even help clarify worries in some scenarios when a parent worries about excessive gassiness, intolerance, or significant urping or spitting up.

Experimentation with formula brands in an otherwise healthy newborn is okay. But it’s not necessary at all, either.

It’s fine to make a bottle that is ½ formula from the blue can and ½ formula from the yellow one. Fine to serve Simulac one week, Enfamil the next, Earth’s Best or Goodstart followed by Soy formula the following day. Fine to buy one brand that’s on sale only to buy the other brand next week.

However, all this being said, I usually recommend families don’t switch often. Let time unfold and give your baby a chance to settle in. Don’t react to every single poop. Give your baby a week or two on a formula before you give up or reach for a new can.

Recently one of my best friends found that when she served her baby organic formula he got constipated but when she used non-organic, he didn’t. She was determined to provide him as much organic food as possible but really hated seeing him strain to poop.

This is where Goldilocks come in. She texted me one night assuming that she couldn’t mix and match formulas, but “just wanted to check and see.” I felt she could. Viola! She found that making the “just right” formula (1/2 organic mixed with a ½ conventional) provided a bit more balance for her newborn son. She found that when she fed him the Golidlocks bottle, the hard stools and potential constipation improved.

Fine by baby. Fine by pediatrician. Mama Bear felt better, too.

Parents often want to buy the formula on sale; they wonder can they switch it up and save money? I say yes. There is no danger in providing your baby differing formulas from one day to the next.

Think of it this way: babies who are breast-fed have a slightly different milk each and every meal due to mom’s variant diet. Although fat, calories, and protein count remain constant, flavor and variety changes. A slightly different recipe at every feed.

Goldilocks Infant Formula Rules:

  • Never add sugar or juice or cow’s milk to infant formula.
  • Don’t fix what isn’t broken. No need to switch formula if no concerns.
  • Don’t dilute or concentrate the formula you make for your baby. Standard powdered formulas usually mix 1 scoop to every 2 ounces of water. Follow directions and use the scooper that comes with the formula.
  • In the US, in my opinion it’s safe to use tap water to mix infant formula. However, some families may want to avoid excess fluoride consumption from tap water for babies exclusively formula fed. Here’s info from the CDC on fluoride for formula feeders. No need to purchase distilled water (in plastic bottles) and no reason to boil water prior to mixing either–if you want, you can remove fluoride with a reverse osmosis filter system.
  • If your baby is super cranky, doesn’t react well to a change in the formula you offer, or you’re worried about a potential intolerance or allergy, talk with their pediatrician about a plan for selecting the best infant formula for your baby.
  • Continue to feed infant formula until 12 months of age. No Goldilocks mixing with cow’s milk or other milk-substitutes prior to that 1st birthday.

Here’s some physician-reviewed information on infant formulas from the NIH:

Standard milk-based formulas:
• Almost all babies and infants do well on these formulas. Fussiness and colic are common problems. Most of the time, cow’s milk formulas are not the cause of these symptoms and parents do not need to switch to a different formula.
• These formulas are made with cow’s milk protein that has been changed to be more like breast milk. Lactose and minerals from the cow’s milk, as well as vegetable oils, minerals, and vitamins are also in the formula.
Soy-based formulas:
• These formulas are made using soy proteins. They do not contain lactose. The American Academy of Pediatrics recommends soy formulas for parents who do not want their child to eat animal protein, and for infants with galactosemia or congenital lactase deficiency.
• Soy-based formulas have not been proven to help with milk allergies or colic. Babies who are allergic to cows’ milk may also be allergic to soy milk.
Hypoallergenic formulas (protein hydrolysate formulas):
• This type of formula may be helpful for infants who have true allergies to milk protein, and for those with skin rashes or wheezing caused by allergies.
• Hypoallergenic formulas are generally much more expensive than regular formulas.