Unpleasant Baby Formula Smell

35 hours of research 5 minute read

" Some parents may find the smell of baby formula to be unusual or unpleasant, but this is no cause for alarm! "

Baby formulas can sometimes have an unpleasant odor, which can be concerning for parents. The reason for this can vary, but it typically relates to the ingredients used in the formula.

Why Does My Baby’s Formula Smell Bad?

Why might a baby's formula smell different?

One possible cause of a bad smell in baby formula is the use of certain types of proteins. For example, formulas that contain hydrolyzed proteins, which have been partially broken down for easier digestion, can have a strong smell. This is because the hydrolysis process can create some unpleasant odors. For example, if you have a child with a severe milk allergy and use "allergy-friendly" formulas such as organic or soy varieties—you may notice that they don't taste as good as traditional supermarket brands. This is due to the fact that these formulas contain less protein (and thus lack flavor). But first, let's figure out why baby formula may smell different.

Is It Normal For Baby Formula To Smell Bad?

Baby formula contains vitamins and minerals that your baby requires, but while it is intended to mimic the nutritional value of breastmilk, the comparison ends there.

Every so often we will receive a note from a worried parent that their formula smells strange, even though they may be generally familiar with the flavor notes of a specific formula. The majority of formula brands have a distinct odor.

It is normal for some formulas to have a less attractive, but distinct odor. In some cases, the smell of formula can be fishy, cheesy, or even slightly metallic. And, because each brand has its unique ingredient list, the way each brand smells will differ.

Metallic Smell Many formula brands have a metallic odor, which is caused by vitamins and minerals in the formula.
Cheesy Smell It's lactose-free and hypoallergenic, which contributes to a cheesy aroma.
Fishy Smell Formulas containing DHA may have a slightly more fishy odor. And depending on the batch and how strong the DHA is, some containers of formula may smell fishier than others. Note that the actual levels of DHA will be consistent with the levels explained on the packaging.
Iron Smell You're probably right if your baby's formula smells like iron! You're probably smelling the iron in the formula.
Musty Smell During transit, the boxes may become dusty or the shipping container used may have a strong smell which can transfer to the box of a formula package and give it a musty odor.

Why Might A Formula Smell Musty?

The cause of this is shipping, where the musty odor of the outside package overcomes the smell of the internal packaging. This is generally caused by the external box coming in contact with dust along the way during shipping, and if the particular dust was strong enough in smell it can temporarily seep into the internal box. The most important thing to note about the musty odor is that it is actually external to the formula, meaning that the actual formula is in no way compromised.

If a musty odor is bothersome, you can remove musty odors with a simple and gentle wash of the branded box packaging using the following steps:

  1. Remove the box or can from the box packaging and smell to see if the odor is still present.
  2. If the musty odor remains on the inside of the box, please remove the silver bag and wash it.
  3. If the musty odor remains on the can, you can wipe it down with a clean towel or wash it.

Please keep in mind that the formula is ready for consumption as long as the internal package is not ruptured during transit.

Bad Smell vs. Bad Formula

Many formulas have an unpleasant odor. However, there is a distinction to be made between the formula smelling bad and the formula going bad.

How Does Spoiled Formula Smell?

The smell will be different if the formula has been spoiled. Even if you don't like the smell of your baby's formula, you're probably familiar with it. If either the powdered formula or the final bottle does not smell as you expect, it may be spoiled, and you should proceed with caution.

Also, if the formula is spoiled, the ingredients begin to separate, causing a difference in the consistency.

Prepared Formula

If your baby refuses to drink the bottle or begins vomiting after drinking it, it could be a sign that the formula was in some way contaminated. A prepared formula can spoil within as quickly as an hour if left out at room temperature.

You should use the formula within 2 hours of preparing it and within 1 hour of starting to feed the baby. To reduce the risk of bacterial contamination, it is not recommended to store prepared formula in the refrigerator for any amount of time.

Powdered Formula - Check The Expiration Date (European Style)

When a powdered formula begins to deteriorate, it will break down and separate. This should be visible, but you'll definitely be able to smell the difference. 

The expiration date on most European baby formula brands is guaranteed to be at least 6 months after purchase. To avoid forgetting, write the date you opened the container on the lid.

Sources of DHA Can Cause Fishy Smells

Another possible cause of a bad smell in baby formula is the use of certain types of oils or fats. For example, formulas that contain fish oil or algae oil can have a fishy or seaweed-like smell. This is because these oils contain compounds that can produce strong odors.

DHA, or docosahexaenoic acid, is an omega-3 fatty acid that is required for brain development in infants. Because of the importance of this nutrient, DHA is now included in the majority of infant formulas.

What Is The Best DHA Source In Formula?

DHA is found primarily in seafood such as fish, shellfish, and algae. Several types of fish and fish products are good sources, with several grams per serving.

Why Is DHA Important for Babies?

  • Growth of the Eyes

    DHA is abundant in the retina. Photoreceptors, the neuronal cells that allow us to see, contain more DHA than any other cell in the body. DHA levels in photoreceptors that are healthy maximize retinal function and protect against damage from bright light exposure and oxidative stress.

  • Growth of the Brain

    When measured in terms of brain weight, the primary growth rate of brain development occurs from birth to years of age. (However, some parts of the brain develop throughout childhood and adolescence.) The tissue content of the long chain omega 3 fatty acid DHA is critical during this stage of development. DHA-rich frontal lobes are thought to be responsible for executive and higher-order cognitive activities such as planning, problem solving, and focused attention, according to research.

HiPP AR, HA, Comfort, Dutch

Fish Oil

Holle Cow

Fish Oil

Holle Goat

Plant-Based Algae


Algal Oil


Plant-Based Algae


Fish Oil


Marine Fish Oil Powder

Aptamil Nutribiotik; Aptamil Gold

Tuna Oil and Algal oil

Do Formula-Fed Babies Require DHA?

Formula-fed babies can get more DHA by eating baby formula with recommended DHA levels. DHA is an essential nutrient in your baby's diet for a variety of reasons, so make sure your child is getting enough to support their development.

DHA Deficiency

DHA is essential for the growth and development of the central nervous system in fetuses and infants. There is also evidence to suggest that DHA deficiency can cause ADD/ADHD, mental retardation, and visual development and function failures, including blindness from retinitis pigmentosa.

Advantages of DHA for Children

  • ADHD symptoms may be improved
  • Asthma may be reduced
  • Improves sleep quality
  • Improves brain health
  • Reduces the risk of heart disease

Strange Baby Formula Smells

Overall, a bad smell in baby formula can be a sign of various things, most typically being the result of a certain ingredient's use in the formula. It's important for parents to pay attention to the smell of their baby's formula and to follow proper storage and preparation guidelines to ensure the safety and quality of the formula. Baby formula contains vitamins and minerals that your baby requires, but while it is intended to mimic the nutritional value of breastmilk, the comparison ends there. If in doubt, it's always best to consult a pediatrician or healthcare professional.

We hope that this blog has provided valuable insights into common questions such as "why does baby formula smell so bad," "why does baby formula smell like fish," and "why does baby formula smell like metal." These concerns can understandably cause worry for parents, as your baby's nutrition and well-being are of utmost importance.

Understanding the reasons behind these unusual smells can help alleviate some of those worries. While slight variations in formula odor can be due to the ingredients used or the manufacturing process, significant and persistent changes should be addressed.

If you ever notice a substantial difference in the smell of your baby's formula or have further questions or concerns about their nutrition or any aspect of their care, don't hesitate to seek advice and guidance. Your baby's health and well-being are always the top priority, and healthcare professionals are there to provide the support and expertise you need.

Most Popular Baby Formulas

  1. HiPP Dutch Formula
  2. Holle Bio Formula
  3. Holle Goat Formula