baby bottle

How Long Does it Take for a Baby to Get Used to Formula Change?

The need to change your baby formula is quite common. New babies, new moms, added to new recipes – new ingredients, sometimes new work together, and sometimes they don’t. In such a case, we go back to the drawing board and try to find the best way forward. Check out My Baby Nursery for all your baby product needs.

The excellent news, babies can change formulas from time to time with little to no issues.

So, if you are looking to change the formula for health concerns or because you want to switch from, say, non-organic to organic, then you will be able to do so.

As for an answer to the question ‘how long does it take for a baby to adjust to formula change?’, we will delve into the research to see what it says and help you figure out what you can expect if you need to make a swap. 

When you choose to bottle feed your baby, you need to consider what type of formula you’ll be providing them.

Not all recipes are the same. One may make your baby spit up, another may cause gas, and a third might be perfect.

The thing is, it’s not good to constantly change your baby’s formula as this can have an impact on them. Babies have underdeveloped digestive systems that are extremely sensitive. So it can damage their stomach.

In addition, you want to make sure that your baby has time to adjust to the new formula. If your little one previously had gas, and they continue to have gas on their new recipe, it could be that they haven’t adjusted yet.

Reasons to Change Formulas

If you’re already using formula consistently (either fully or as a supplement to breast milk), you might wonder why someone would want to change formulas in the first place.

But, there are plenty of reasons why it could be wise to change your baby’s formula. Here are a few: 

The baby negatively reacts to the formula.

Baby Tips

When it comes to your little one, it’s hard to know what works and does not work for your baby.

In most cases, it’s a matter of trial and error. Some new moms might find that while the baby accepts a particular formula brand, they notice some form of reaction later on. 

Allergic reactions may be a common sign that your baby is having a negative response to the formula.

However, to know for sure, you should contact your healthcare provider. If your baby has allergies, you need to switch recipes.

If they have a milk allergy, switching to soy formula is usually best.

If they have other allergies, switching to a hypoallergenic formula or all-natural formula might be safer.

Safety should always come first, and allergies can cause dangerous respiratory symptoms.

Furthermore, some mothers might find that their baby starts to react more outwardly hostile toward a given formula.

Babies may cry, get gassy, spit up or experience unfavourable bowel movements due to procedure. 

Try to keep a close monitor on your baby and use a baby journal to record whatever you may notice.

While the above may be symptoms of a reaction to the specific baby formula, you will need to talk to an expert to confirm. Any signs of issues with your baby should always be taken seriously and acted upon. 


You don’t always need a health reason to switch formulas.

Some parents discover that a particular brand is made with more natural ingredients or does not use GMO’s, and they would prefer to give their baby that.

If you have a particular preference as you learn more about different types of formula, there is nothing wrong with switching your baby to something that you deem to be better for them.

Digestive Issues

Some babies handle specific formulas better than other ones. 

Vitamin Deficiency

If your little one has a vitamin deficiency, they might need to switch formulas like low iron.

Some recipes are fortified with iron or other vitamins to give your baby the required boost if infant vitamins aren’t enough for them.

The baby requires more at each feeding – Price Concerns.

Infant formula can be pricey, especially as you’re looking for the best recipe for your baby.

As babies grow to the six-month mark, they progressively need more and more formula until they start consuming solid foods alongside liquid foods. 

Let’s face it: baby formulas are expensive! If you started on the most costly formula and want to switch to save some cash, that’s fine too.

This is one of the popular reasons that parents change procedures.

Certain brands are cheaper. Some brands don’t seem to have an off-brand version available.

TIP: Buying a cheaper brand or buying in bulk online are both excellent ways to save money on formula too!

Until that point, parents can be overwhelmed with the cost of baby formula. They might find a suitable replacement that has the same nutritional content but is cheaper overall. In this case, it may prove financially wiser to switch to the cheaper but still worthwhile formula.

Another Formula May Be More Nutritious

As times change and production gets better, some moms may notice that a new formula seems more nutritious or better serve their baby’s needs than their current formula. 

Alternatively, they might meet up with their pediatrician and be given a directive to find a new formula brand with more of a particular nutrient, vitamin, or mineral.

For instance, as their baby gets older, doctors may recommend the need to pursue a formula with a bit more iron or the like.  

Whatever your reason, remember that it’s very much okay to switch formulas, and it is a normal part of the process. 

Before getting further into this topic, it may be fair to say that no two infant formulas are made the same.

However, you may want to ensure still that you do not experience the same issues after switching, which is why the next point is so important.

How Long Do Babies Need To Adjust To New Formula?

Some babies will adjust to a new formula in a week.

Other babies might take longer, up to six weeks. Instead of giving your baby a timeline, it’s better to pay attention to symptoms and discomfort.

One of the easiest ways to do this is to document it.

For example, if your baby was constipated, keep track of how often they have a bowel movement.

Note any new symptoms, such as gas or signs of discomfort.

As you keep track of those symptoms, you can review previous symptoms so that you can see if your baby is starting to improve or not.

If they are not, they might not have adjusted yet or need a different formula. If your baby hasn’t improved in three weeks, give your pediatrician another call.

Switching Formula Brands

Switching from one type of formula to another is common, but most people worry about switching brands. Not all brands are made the same, but switching between brands is excellent.

Remember that it might take a little bit longer for your baby to adjust to the new formula, though. Give them a week or two to determine if they can tolerate the new procedure.

Transitioning To A New Formula

If you decided to give your baby a new formula, there are two ways to do it.

You can switch cold-turkey to a new recipe, or you can transition into a new procedure. There are pros and cons to both ways.

Switching All At Once

If you switch all at once, it means that you abruptly stop giving your baby one formula and immediately switch to another.

This is common for parents to change due to allergies, but there are a few things to know first.

How Long Does It Take For A Baby To Adjust To Formula Change?

When you switch all at once, you can go through an adjustment period. Some babies will adjust within a few days, but others might take weeks to change. It depends on your baby and the formula.

Switching from soy formula to a milk-based formula will be harder on the digestive system, and it might take your baby a while to get the hang of digesting it.

While you’re going through the adjustment period, you might notice that your baby has sporadic gas or tummy troubles. This is normal.

If the problems persist, discuss other options with your pediatrician, or ask them how long it takes for the baby to adjust to formula change. They will have experience regarding the specific formula that your baby is on.

Slowly Transitioning

Slowly transitioning your little one from one formula to the next involves mixing recipes. You substitute a little bit of the old formula with the new formula. Then, each day you add a little bit more of the new procedure to the bottle until your baby is only drinking the new formula.

How Long Does It Take For A Baby To Adjust To Formula Change?

baby bottle

When you slowly transition your little one, you will have a more extended adjustment period.

It will take a week to switch to the new formula completely, so you won’t be able to see how well they adjust until after that. The adjustment period is usually a bit different than switching formulas suddenly.

Fewer Side Effects

Babies that are suddenly switched from one formula to the next might have gas or indigestion from the switch, especially if you switch brands.

When you slowly transition formulas, your little one will have enough transition to get used to the new procedure. This means that they will have fewer digestive problems.

When Should You Transition Slowly?

Transitioning slowly is ideal if your baby does not have allergies or severe discomfort from the previous formula. It’s also a great idea if you are switching between brands.

If you don’t have to switch suddenly, go with transitioning slowly to give your little one time to adjust.

How to Change Formulas

So, how do you go about actually switching formulas? 

You should consult a trusted caretaker or your loved one before making a switch.

Your baby’s health care professional is just that – a professional.

They would’ve advised other mothers on how to switch formula dozens of times before, and they might have their tips to share regarding the process and making it a smooth one.

They will also be able to give you direct pointers regarding which formulas you should look for. 

Once you’ve spoken to your baby’s doctor and found a suitable replacement, don’t expect things to change overnight.

Babies can be pretty fussy and love their routines – so adjusting may take some time. All that is needed is a little more time and some patience on your part. 

Use a gradual process. 

You should introduce the new formula slowly if your baby is picky with bottle feeding.

Try to give them a little bit of the new procedure during the middle of the day or whenever your baby is historically happier or calmer.

This keeps your little one grounded and feeling like their world isn’t changing too much or too fast.

This being said, you can always switch formulas right away if needed.

It all depends on your little one and their personality or sensitivity. Or if the need to change was due to health or allergy concerns. 

However, switching gradually instead of right away may be a good choice.

It would help if you fed your little one more of the new formula over time and keep an eye on how their body handles the change. 

Check their demeanour and even their diapers for any significant changes. 

Monitor how much food they continue to eat.  

If all seems good, continue to increase the new formula amount until it’s replaced the old formula entirely. My Baby Nursery is your one-stop baby product store.

How Long to See a Real Change?

The pressing question was, how long does it take for a baby to adjust to a formula change?

In most cases, it can take about a week to ten days for a new formula brand to fully settle in your child’s digestive system.

You might get an immediate response from your baby in terms of flavour or preference, but it’ll take at least a couple of weeks to see actual improvement, if at all or, even a change for the flip side of things. 

Sometimes, you may not notice a change, and that is okay and even welcomed.

If you’ve switched your baby to, say, an organic formula – you may not physically or immediately see any changes; however, you know that the switch was for the best – based on your definition.  

Of course, if you’re switching formulas because the last type of formula was causing health concerns, improvement should be immediate whenever you change.

This is especially true if your baby has a milk allergy to cow’s milk and you are switching to a hypoallergenic formula or a soy formula. 

Talk to your doctor if things don’t improve after using a formula to take care of any allergic reactions or the like.

Signs Your Baby Is Having A Hard Time With The New Formula

Sometimes, you’ll realize that you just switched formulas, and your baby is having a hard time with the new one.

This isn’t always easy to spot, though. Watch for these signs that your baby might need to switch formulas again.

Allergic Reaction

If your baby has any signs of an allergic reaction to a new formula, it’s essential to switch his formula and contact your pediatrician immediately.

This is something to watch out for if your baby was previously on soy formula and you’ve changed them to one that is milk-based.

Milk allergies are common in infants. Allergic reactions can be mild or severe. Symptoms include:

  • Rashes
  • Hives
  • Vomiting
  • Excessive diarrhea (some diarrhea in infants is regular. Contact your pediatrician to determine if your baby falls within the normal range.)
  • Respiratory problems

Every formula is not created the same.

If you recently switched formulas and have noticed a sudden onset of these symptoms, it’s a sign that your baby might have an upset stomach from their new recipe.

  • No longer sleeps through the night
  • Cries more frequently
  • Tenses up
  • Excessive gas, constipation
  • Vomiting
  • Grimaces or scrunched up face as though they are in pain

What To Do If Your Baby Is Having A Hard Time Adjusting?

Although it makes sense to switch formulas again, that’s not always the answer.

If your baby has an allergic reaction, you’ll need to change procedures.

If they have a mild symptom, like gas, there are other things you can try.

Gas relief drops and burping your baby more while feeding them can both work to alleviate gas in infants.

If you’re not sure, contact your pediatrician.

They are there to help your baby when they’re sick and provide you with guidance as you strive to be the best mother you can be.

Should You Mix Formulas?

In most cases, it is not advisable to mix two formulas.

Mixing formulas can be tricky when you’re testing to see if the new formula works well with your infant’s body.

Or if you are switching formulas due to allergic reactions. 

When formulas are mixed, it may be difficult to tell whether the old recipe is acting up again or if the new procedure is to blame.

Plus, some formulas don’t mix well together.

However, some sources have cited that it may be okay to mix the two if you switch for preference.

For instance, you are changing from a non-organic to an organic formula.

You may be able to add one scoop with knowledge of the next just until your baby adjusts to the procedure. You can always run this by your pediatrician for more clarity. 

Other Things to Consider When You Switch Formulas With Your Baby

It’s not uncommon for babies to have strange digestive reactions to things.

Their bodies are more sensitive, so even a formula that will eventually end up settling with their system could cause minor issues at first.

This is normal, so you have to stick with it for up to 8-10 days. Again, don’t hesitate to contact your doctor for any reason.

It is also customary to be concerned, and all your questions are valid. 

If you notice any concerning reaction post switching, you may undoubtedly cease the new formula and go back to the old recipe until you find a better solution–while voicing your concerns.

You don’t have to introduce the new formula gradually by either alternating or combining it with the old formula-you can switch over to the new recipe right away.

Mixing formulas is not recommended because if your baby does not do well on feeding, you won’t tell which recipe or ingredient is causing the problem.

Also, the formulas may not mix well.

Make sure you give your baby enough time to try the new formula, usually 3 to 5 days. Some babies will adjust right away.

Others may have slight changes in stool pattern, gas, and spitting until they become accustomed to the new formula. If you have questions or concerns, check with your baby’s doctor.

To that end, don’t throw out all of your old formulae when you get the new brand.

You may need to go back to what you and your baby know, at least temporarily, until you make sure that the new formula is precisely what’s suitable for your situation and your baby’s unique needs.


All in all, it can take your baby some time to adjust to a new formula, but the exact timeframe will vary from infant to infant–up to 10 days is a reasonable time frame if you are noticing adverse effects.

Expect to spend that amount of time both getting your baby used to the new formula and waiting for their body to give you a sign that everything is running smoothly. 

Gradual progress and change are expected, so don’t worry if the improvement isn’t immediate.

Keep in regular contact with your doctor and update them on the progress of the switch so they can assist you if anything more serious comes up. Online baby product directory at My Baby Nursery.

When it comes to formula feeding your baby, every answer is unique. That’s why we’re always here if you have other questions about the procedure or different motherhood needs. Let us know how we can help!

Scroll to Top