Skip to Main Content
What to Expect When Switching Baby Formula

What to Expect When Switching Baby Formula

Navigating formula switches and when to ask your doctor if it’s time for a change.

Every baby is special–even siblings can have very different preferences and needs for baby formula, so it’s perfectly normal to have that conversation with your doctor about a formula that just doesn’t seem to be working. If you decide with the guidance of your doctor to switch formulas, you might notice some changes in your baby's behavior and bodily functions–hopefully for the better!

How long should you try a formula before switching?

Many doctors will recommend trying a formula between 3-5 days before deciding to switch. If you’re ever not sure a formula is a good fit for your baby, it can’t hurt to reach out to your doctor for guidance. Depending on what your issues or concerns are, your doctor may come up with a different plan and different timeline.

Always ask your doctor before you switch

Every baby is different, and that’s why it’s so important to consult your doctor about switching baby formulas because your doctor is able to make recommendations for your baby’s individual needs.

You can ask your doctor these 5 key questions to help you get clarity about what to expect for your specific circumstances:

  • How soon will I know if the formula is a good fit for my baby?
  • How long should we try this formula before we decide to try something else?
  • Have we ruled out the possibility of other things that could be causing the issues my baby is having?
  • What are some things that might happen when I make this switch that are normal and not to worry about?
  • What are the things I should look out for and call you right away if I see them?

Anticipate comfort

One of the most common reasons doctors recommend switching formulas is to address feeding or digestive issues, such as excessive spit-up, gas, constipation or some sort of allergy.

In these cases, you should hope to see relatively fast results. Your doctor can give you the best idea of how long you should try a new formula until it seems to be a better fit for your baby. If the issues persist, check back with your doctor to see if there might be a different root cause, or if it’s time to try another formula.

If you experience feeding issues from switching formulas

When you switch to a new formula, it can be normal to notice some changes in poop color, smell, and consistency.

  • Stool color: You might see greener poop, for example. This could be due to the presence of nutrients like iron in the new formula that pass through your baby's stool. However, if you notice a concerning color that looks like blood, you’ll want to let your doctor know right away.
  • Stool consistency: Some nutrient may make stools little bit harder in texture. Keep an eye out for any indications that your baby might be struggling to poop.
  • Prebiotics: Sometimes introducing prebiotics can make babies a bit gassier and their stools a looser and softer at first. You can always ask your doctor about what sort of timeline to expect for your baby’s body to adjust.

Baby might need some encouragement to try it

It’s not uncommon for babies to hesitate to try new formula–and while we can’t always know for certain, there are a few things that could explain why your baby might need some encouragement to try the new formula:

New routine

We can all be creatures of habit sometimes. If you have a baby that loves routine, it can help to make sure you’re giving them the new formula in the same bottle and during the same feeding times.


Think about how overwhelming it must be for a baby to experience something new every second of every day! Sometimes it just takes time to warm up to new things, especially if your baby has had a busy day. If you can, introduce the new formula at a time when baby is calm and/or hungry.

The body is adjusting

Sometimes we have involuntary reactions to new foods–if the body isn’t used to it, it might reject it at first. Many doctors recommend introducing the new formula in small doses, mixed with the previous formula so that your baby doesn’t feel such a dramatic switch all at once. Always be sure to get clarity from your doctor about when, how much, and how often to feed your baby.

Negative association

If your baby has had negative experiences with a previous formula, they might not understand that you’re giving them something different. Try to encourage them by feeding the new formula when they’re hungry and calm. Your enthusiasm and positive energy might also encourage them to feel good about giving the new formula a try.

It just takes time

Sometimes we’re blessed with a baby that has a strong will, and patience goes a long way. Sometimes we just have to hang in there and keep showing that love that we all have for our children, and trust that we’ll figure out what works eventually. You’re not alone–everyone has ups and downs with feeding babies, but just as quickly as someone can remember the difficulties they had feeding their baby, they can tell you just as quickly it was worth it.

Switching formulas for additional nutrition

Some babies need extra nutrients, and sometimes parents want to get the most nutrition they can from formula. There doesn’t always have to be a problem for a formula switch–if you’re interested in giving your baby additional nutrients not found in other regular formulas, don’t hesitate to ask your doctor about switching to premium formulas that offer those benefits.

Switching formula within the same brand

Whether you’re considering switching within a brand or from one brand to another, the most important thing to compare are the ingredients of the formula. When considering your options with Enfamil, you can always expect to see high-quality, commitment to safety, and complete nutrition in every one of our formulas.

Enfamil also offers loyalty incentives such as rebates, coupons, and formula discounts for members of Enfamil Family Beginnings. There is no cost to joining or being a member, plus you get exclusive access to tips and promotions that can be helpful in your parenting journey.

Wherever you are in your formula finding journey, Enfamil is here to support you every step of the way. Explore our family of formulas to explore and compare your options with the #1 recommended brand by pediatricians.

Frequently asked questions

All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.