How to Change & Transition to Baby Formula

• Breastfeeding is recommended as the best source of nutrition, but formula may be introduced for personal or medical reasons.
• Always consult a healthcare professional before making significant changes to your baby’s feeding routine.
• Formula is the only safe alternative to breastfeeding.
• Infant formulas in Australia are staged to reflect changing nutritional needs as babies grow.
• Introduce new formulas gradually unless otherwise advised by your healthcare professional.
• Mild, temporary changes in digestion or feeding patterns can occur during a transition.
• Seek medical advice if your baby experiences persistent vomiting, blood in stool, a rash, or severe distress.
• Always prepare formula according to the manufacturer’s instructions, using sterilised equipment and correct measurements. This is especially important when changing infant formula brands as preparation directions vary between brands.

Prior to introducing infant formula for the first time, a healthcare professional should be consulted. Healthcare professionals are best placed to support women, especially those who wish to continue breastfeeding either fully or partially. They can do this in a number of ways including navigating feeding challenges, discussing techniques to protect and maintain supply and can provide direction to services that provide information on the right to breastfeed at work and in public places.

There are many reasons why you might be considering a transition to infant formula. While the benefits of breastfeeding are well known, it may not always be possible for every family. Some  may choose to introduce formula due to returning to work, while others may need to initiate the transition due to low milk supply or medical considerations.

For some families, formula may be used to supplement breastfeeding, while others may decide to transition fully. Speaking with a healthcare professional can help you determine the most appropriate approach for your baby.

As babies grow, their nutritional needs also change, particularly around 6 months of age when solids are introduced. In Australia, infant formulas are staged to reflect these developmental shifts.  Stage 1 formulas are suitable from birth and can be used right through to 6 months, while Stage 2 formulas are designed for babies aged 6–12 months. Switching from Stage 1 isn’t always necessary and many families continue using Stage 1 beyond six months if preferred or advised by a healthcare professional. 

You may also consider changing formulas if feeding challenges arise, such as reflux, colic, constipation, or excessive gas. Suspected cow’s milk protein allergy or lactose sensitivity should always be assessed by a healthcare professional who may recommend a specialised formula if needed. While all infant formulas sold in Australia meet strict regulatory and nutritional standards, individual tolerance can vary, which is why any transition should be approached gradually and with professional support. 

Consult your health professional

Before making any significant changes to your baby’s feeding routine, it is essential to consult a healthcare professional. A GP, paediatrician, child health nurse, or Accredited Practising Dietitian can assess your baby’s growth, feeding patterns, digestive symptoms, and medical history to determine whether a formula transition is necessary.

It can be tempting to self-diagnose allergies or intolerances based on common behaviours such as fussiness or changes in bowel movements. However, many of these signs can be part of normal infant development. This is why changing formula without professional guidance is not recommended.

Medical advice is particularly important if your baby is experiencing poor weight gain, blood in their stool, persistent vomiting, eczema that appears linked to feeding, or if they were born prematurely. A licensed professional can provide guidance on how to transition from breastfeeding to formula in a way that safely supports your baby’s needs.

Why babies need formula rather than cow’s milk

Infants under 12 months should not be given regular cow’s milk as their main drink. While cow’s milk can be part of family meals in small amounts once solids are introduced, it does not provide the right balance of nutrients needed to support infant growth and development.

Baby and infant formula, on the other hand, is specifically formulated to provide appropriate levels of key nutrients when breastfeeding is not possible or not chosen. It is designed to support healthy growth and development during a baby’s first year. specifically formulated to provide appropriate levels of key nutrients when breastfeeding is not possible or not chosen. It is designed to support healthy growth and development during a baby’s first year.

There are many situations where formula feeding may be appropriate. As with any feeding decision, it is important to consult your healthcare professional before making changes.

Some babies can switch to a new formula straight away without any issues. However, if your baby has a sensitive tummy or if you’re concerned about digestive upset, a gradual transition can be a gentle and supportive approach.

If you and your healthcare professional decide that a formula change is appropriate, introducing the new formula slowly can help your baby adjust comfortably while allowing you to observe how they respond and ensuring they continue to receive consistent nutrition.  

Unless an immediate transition to recommended by a healthcare professional for medical concerns such as an allergy, some infants may benefit from a gradual transition

Below is a gentle, step‑by‑step method for babies who have five formula feeds per day. You can adjust the schedule based on your baby’s feeding routine and the timing depending on how your baby is adjusting.

Note: Immediate transition may be recommended by a healthcare professional for medical concerns such as allergies.

Step 1: Start slowly, introduce one bottle of the new formula

For the first 1–3 days, replace one feed with the new formula.

It’s best to introduce the new formula during daylight hours, ideally a morning feed or the first feed of the day, so you can monitor your baby’s tolerance throughout the day.

For example:

• Morning feed: New formula
• All remaining feeds: Current formula

Step 2: Add a second feed of the new formula

Once the first step is going well, introduce the new formula into two feeds per day. Continue this stage for another 1–3 days, adjusting as needed.

For example:

• First feed: New formula
• Third feed: New formula
• All other feeds: Current formula

Keep your baby’s usual feeding schedule the same. During this stage, watch for changes in feeding behaviour, comfort, wind, or bowel habits.

Step 3: Gradually increase to mostly new Formula

Over the next several days, begin offering the new formula for the majority of feeds. Go at a pace that feels right for your baby.

For example:

• First, third, and fourth feeds: New formula
• Remaining feeds: Current formula

If your baby continues to tolerate the new formula well, you can increase to four feeds of the new formula before moving fully across.

Step 4: Fully transition to the new formula

If your baby is feeding well and appears comfortable, you can move to 100% of the new formula.

Continue to monitor your baby’s overall wellbeing and consult your healthcare professional if you have any concerns at any stage of the transition.

Transitioning between stages

Moving from Stage 1 to Stage 2 formula typically happens at around six months of age and often coincides with the introduction of solid foods. Follow-on formulas are formulated with adjusted nutrient ratios to support the changing needs of older infants as their diet expands.

Switching from Stage 1 to Stage 2 formula isn’t always necessary unless advised by a healthcare professional. Remaining on Stage 1 may be more beneficial as there are many changes occurring with the introduction of solids, and this can be one aspect that remains the same, smoothing the transition for your baby.

Before making the switch, check that your baby meets the recommended age range stated on the product packaging and speak with your healthcare professional if you are unsure. Every baby develops at their own pace, so ensuring readiness can help support a smooth transition.

Transitioning to specialty formula

Switching to a specialty formula, such as one designed for reflux, colic or allergy concerns, should always involve medical guidance. A healthcare professional can assess your baby’s symptoms, growth, and medical history to determine whether a specialty product is appropriate.

In some medically indicated situations, your healthcare professional may recommend moving directly to the new formula rather than introducing it gradually. A medical professional can advise you on how to change baby formula brands safely.

During a formula transition, it is common to notice some mild, temporary changes as your baby adjusts to the new product. Every baby responds differently, but small variations can be part of the normal adaptation process.

You may observe:

• Changes in stool colour, texture, or frequency
• Mild gas or temporary fussiness
• Slight shifts in feeding patterns or appetite

These changes are often short-lived. However, seek immediate medical advice if your baby experiences persistent vomiting, a rash that appears linked to feeding, blood in their stool, or signs of severe distress. If you are unsure whether a symptom is normal, consult your healthcare professional.

Throughout the transition, follow safe preparation practices. Always sterilise bottles and equipment, use the correct scoop provided, and measure water and powder according to the manufacturer’s directions.

Temporary changes in stool colour, texture, or frequency

It is normal for bowel movements to look slightly different when changing formula. Stools may vary in colour or become a little firmer or looser for a short time as digestion adjusts.

Mild gas or fussiness as digestion adjusts

Some babies may appear mildly unsettled or gassy during the early days of a transition. This is often temporary while their digestive system adapts.

Feeding pattern changes

Your baby’s appetite or feeding rhythm may shift slightly. They may drink a little more or less than usual for a few days as they become familiar with the new formula.

Infant formulas sold in Australia are regulated to meet strict nutritional and safety standards. They are typically categorised by stage and purpose, reflecting the different developmental needs of babies as they grow.

• Stage 1 or starter formula: Suitable from birth, Stage 1 formula is designed to provide complete nutrition for infants who are not breastfed or who are combination fed. It supports healthy growth and development during the early months of life.
• Stage 2 or follow-on formula: May be  introduced from around six months, Stage 2 formula is formulated to complement the introduction of solid foods. It contains adjusted nutrient levels to support older infants as their dietary needs evolve.
• Specialty formulas: These are developed for specific medical or feeding concerns, such as reflux or allergy-related conditions, and should only be used under healthcare professional guidance.

Choosing and transitioning baby formula is a personal decision that should be guided by your baby’s age and individual needs. While all infant formulas in Australia meet strict standards, individual tolerance can vary, which is why careful observation and correct preparation are important.

If you have questions, our experienced team and Accredited Practising Dietitians are here to help. Contact the a2™ Careline to learn more about supporting your baby’s feeding journey. You can also visit our Feeding Support & Resources page for more resources.