Can I Mix Breast Milk With Formula?

It’s okay if your baby needs some supplementation to breastmilk. Parents may choose to introduce formula as a supplement from having a low milk supply, different medical conditions, or you’ve had multiple babies. Infant formula can help provide your baby with the nutrients needed to develop and grow. It is safe to mix formula and breastmilk in the same bottle.


Whether you are bottle-feeding or nursing, your baby is provided with nutrients that only breastmilk can give infants.

The number of proteins, fats, carbohydrates, and other vitamins cannot be duplicated with prepared formula.

Furthermore, studies have shown that it contains antibodies for protection, prevents obesity and Type 1 diabetes, and reduces the risk of sudden infant death syndrome (SIDS).

So yes, nursing and exclusively pumping to feed your baby breast milk is the standard recommendation. But life doesn’t always allow for the perfect scenario all the time.

There may be scenarios that lead to you needed to supplement with formula, and there is nothing wrong with that.

Before combining that powdered formula with water, think about the possibility of mixing with breastmilk instead. 

Types of Formula 

No matter how old they are, you always want to put the best ingredients into the food you prepare for your children.

Supplementing with baby formula should be no different. Aside from breastmilk, it is their only supply of fats, carbohydrates, sodium, vitamins, minerals, water, and other essential nutrients.

The basic ingredients of most formulas are the same, but there are several different types you can pick from. 

  1. Milk-Based Formula – Babies younger than 12 months shouldn’t drink cow’s milk. But this formula is modified to be safe for most babies. 
  2. Hydrolyzed Baby Formula – This is also known as a predigested formula. It contains amino acids that are already broken down, making it easier for the baby to digest. 
  3. Organic Formulas – Usually, these are milk-based formulas but were produced using no pesticides, herbicides, antibiotics, or growth hormones. 
  4. Soy-Based Formulas – These are created from soybeans with nutrients added. Experts suggest that this type of formula only be used with babies that are intolerant to galactose. 
  5. Specialized Formulas – Premature Babies, those with low birth weight, or those with an allergy to lactose require specialized formulas. 

Always talk to your pediatrician before switching formulas or if you have any questions. 

Why Would I Want to Mix Formula and Breastmilk? 

There are so many discussions about the difference between breastmilk and formula. What no one talks about often enough is combining the two sources of nourishment for your baby throughout the day.

You’ll still provide your infant with the nutrients from breastmilk, but they won’t continue to be hungry because they only had a small amount.

The following situations are examples of why you would use a combination: 

1. You are having difficulty with your milk supply

Unfortunately, some mothers can’t produce enough milk to keep their little ones satisfied. They might try all the tricks – hydration, modifying their diet, and pumping regularly – but still cannot supply the amount their baby wants. Changes in hormones, breast augmentations, medications, and even age can contribute to the lack of production.

2. You’ve had multiple babies at once

Having more than one mouth to supply milk can create a drought! If you have previously pumped breast milk, you can mix it with a bottle of formula. 

3. You haven’t been getting enough sleep

Parenting, in general, is a difficult task, and it is okay to ask for help. If you need a break from feeding your child, ask your partner to step in to feed your baby a bottle of formula. A few extra minutes of rest, at any point in the day, can refresh any parent.

4. You’re returning to work

Many mothers do not mind pumping at work to keep an ample milk supply going. However, if that is not something you want to juggle, consider providing baby formula during the day. You can breastfeed before and after work, and the caregiver can supplement with formula during the day. 

Can I Mix Formula and Breastmilk in the Same Bottle? 

If you don’t want to switch exclusively to formula feeding, you can mix the two together in the same bottle.

If you choose to do this, there are some safety guidelines that you need to be aware of. Improper mixing can lead to an over-concentration of nutrients which can be harmful to your baby. 

Powdered baby formula is designed to be mixed with water and provides a certain number of calories per serving.

When you begin to add things to it, even breastmilk, you change the ratio of nutrients.

The water used for the prepared formula helps the kidneys process the nutrients. If it is not diluted, it is potentially too concentrated, and babies cannot process it. 

How to Safely Combine Breast Milk and Formula

According to the Centers for Disease Control and Prevention (CDC), when preparing a bottle of formula, you should use water supplied from a safe source.

No matter what kind of formula you are using, you’ll want to follow the recommended measurements on the container.

If you use too much water, the nutrients become diluted, while not enough water strains the kidneys.

After it has been mixed properly, you can add your breastmilk to the bottle. Ready-to-feed formulas do not require water and can be combined directly with breastmilk. 

Advantages to Mixing 

  1. When your baby first tries formula, they may not like the taste. Mixing it with breastmilk can make this an easier transition. Eventually, your baby will adjust to the new flavor and be able to drink it alone. 
  2. It may help your baby sleep longer since it takes longer for the formula to digest compared to breast milk. It is not recommended to use this method regularly to get your baby to fall asleep. 

Disadvantages to Mixing 

  1. If you are making large batches and your baby doesn’t finish the bottle, you could end up wasting precious breastmilk. Make smaller batches or feed your baby a bottle of breastmilk first and then a bottle of formula. 
  2. Your breastmilk supply may reduce. As the frequency of expressing breastmilk decreases, the supply naturally adjusts. Slowly supplement with formula to keep the production of breastmilk going until you are ready to stop altogether. 
  3. As previously mentioned, there are health risks with mixing breast milk and formula. Improper mixing can lead to kidney problems. It also has a shorter shelf life of one hour.

Are There Any Alternatives? 

When milk alone is not enough for your baby, experts do recommend combination feeding. This is a method where you feed formula and breastmilk but at separate times.

It gives your baby the benefits of “liquid gold” without the risks involved in combining it with formula.

Combination feeding, or mixed feeding, shouldn’t be done without the supervision of a certified lactation consultant or board-certified doctor.

They will help you learn the correct way to mix formula with breastmilk and what works best for your baby.  

Mixing Breast Milk and Formula Is Okay, If Done Safely

There are numerous reasons that parents would want to add a formula supplement to breastmilk.

Whether milk supply is low or the baby needs additional nutrients, mixing the two is a safe and effective way to take care of your baby.

If you follow the guidelines for preparing formula and storing breastmilk, there are many fewer risks.

If you have any concerns about providing supplemental nutrients to your baby, talk to your pediatrician.