Hydrolysate or Hydrolyzed Formulas vs. Amino Acid-Based Formulas

Posted 1.6.11 | Christine Graham-Garo

Quite often, we receive calls from families who are distraught and worried after trying five or six different infant formulas that their child with food allergies was not able to tolerate before finding Neocate, an amino acid-based formula. Often, the formulas they tried in the past were hydrolyzed, or hydrolysate, formulas (such as Alimentum and Nutramigen), which are labeled as hypoallergenic. So I often hear the question. “If this formula is hypoallergenic, why didn’t it work for my baby with food allergies?”

In order to answer this question, I’ll need to explain exactly what a hydrolyzed or hydrolysate formula is and how they differ from amino acid-based formulas, which are sometimes called elemental formulas. The main difference is: hydrolyzed formulas have partial milk proteins in them. Amino acid-based formulas, like Neocate, are milk-free and made up of non-allergenic amino acids, which are the building blocks of protein. That means there is a very slim chance of a child having an allergic reaction to them, as a typical allergic reaction is a reaction to protein.

The reason hydrolyzed formulas can be labeled as hypoallergenic is that the milk proteins in those formulas have been broken down (or hydrolyzed) so that the body’s immune system may not detect the proteins as being an allergen. But with the number of calls we get from families in distress over their little one not tolerating the hydrolysate formula, I can tell you that it is not always the fix-all for a child facing food allergies. This is where an amino acid-based formula comes in. It is sometimes stated that amino acid-based formulas are “super” hypoallergenic, or the least allergenic option. This could be interpreted to mean that amino acid-based formulas are more hypoallergenic than hydrolyzed formulas, although both types of formulas fit the American Academy of Pediatrics' (AAP) criteria that an infant formula must meet to be labeled hypoallergenic.

In general, studies show that amino acid-based formulas are tolerated by almost all severely food-allergic babies. Although many food allergy babies tolerate hydrolyzed formulas, there is a subset that do not - often having symptoms like severe diarrhea, vomiting, rashes and failure to thrive. If you're concerned that your little one isn't tolerating a hydryolyzed formula, talk to your baby's doctor.

A review of scientific research addressed the intolerance concern with hydrolyzed formulas by stating that “there are clinical benefits from the use of amino acid-based formulas in both symptoms and growth in infants and children with cow’s milk allergy who fail to tolerate extensively hydrolyzed formula”1. Another study showed that up to 30% of babies with complex food allergies did not tolerate the hydrolyzed formula ised inthe study2. This is important to know especially if your little one (or someone else’s infant) is still displaying signs of food allergy and is currently using a hydrolyzed formula.

Did your child not tolerate a hydrolyzed formula? What did you do?

- Christine

1 Hill DJ, The efficacy of amino acid based formula in relieving the symptoms of cows milk allergy-A systematic review. Clin Exp Allergy. 2007.
2 Latcham et al, A consistent pattern of minor immunodeficiency and subtle enteropathy in children with multiple food allergy. J Pediatr. 2003.

Read Comments (32)

  • 2013-05-30 | keshia Lankford

    My daughter (2months) has been threw all the formulas enfamil newborn, prosobee, alimentum, pregestmil, and neocate she was tested positive for blood in the stools what’s next? We have a GI specialist appointment on tuesday. If neocate is supposed to be a amino acid based why couldn’t she take it?

  • 2013-06-07 | Christine Graham-Garo

    Dear Keshia,
    How long did you trial the Neocate? Studies say to trial elemental formulas for about 2 weeks. It takes time for the gut to heal all the way.  Its great that you are seeing your doctor soon.  There are other options beyond elemental formulas, but usually these options are the last case scenario. The modular approach is an example. Another option is to try another elemental formula on the market. You will need to talk to your doctor about these paths. But again, I would suggest that you stay on the Neocate for the 2 week period. Hope this helps. Best wishes to you and your little one!

  • 2013-11-14 | Lauren


    My daughter has been on neocate for 3 weeks and has had some improvement, but not much.  When you told Keshia a modular approach or another elemental formula on the market was an option, what did you mean by that?  What would the modular approach be, and what other formulas are out there that would possibly be beneficial?

    Thank you,

  • 2013-11-20 | Christine Graham-Garo

    Hi Lauren,
    Other elemental formulas on the market in the US are Elecare and PurAmino.
    A modular approach is where you basically create your own formula. You must work with your doctor and/or dietitian on this approach. For exmample, you can use a protein source (we have the Complete Amino Acid Mix that can be used), a fat source, and a carbohydrate source, along with vitamins and minerals appropriate for your child. Hope this makes sense. Talk to your doctor or dietitian for more information.

  • 2014-01-17 | Laurie

    My baby has a milk protein allergy.  I was breastfeeding removing dairy and soy but he wasn’t gaining weight.  We went to all formula - Alimentum.  He could not tolerate the powder spit up a lot and had a horrible rash on his bum.  Ready to Feed seems ok but again he is spitting up a lot.  Is there something in just the powder formula bothering him?  If so does Neocate contain this?  I would like for him to take a powder.  RTF is expensive and logistically difficult.

  • 2014-01-21 | Christine

    Dear Laurie,
    Both the ready-to-drink and the powdered Alimentum have milk proteins. The milk proteins are broken up which can help with some milk allergic infants, but it doesnt help all infants allergic to milk. Im not sure what is in the powdered Alimentum that would cause the issue. You can call Alimentum to ask. 
    Neocate is different from Alimentum because it is 100% dairy/milk free. Its hard to say exactly what is causing the issue. Rashes and reflux can be milk allergy symptoms.  Neocate may be a good option. Speak to your doctor about Neocate so you are all on the same page.

  • 2014-04-11 | Cynthia

    Response to Laurie, 2014-01-21 Alimentum Powder has corn in it that can cause intolerance to formula. Alimentum Ready to Feed is the only formula without corn. When corn intolerance is a factor, even the elemental formulas (Elecare, Neocate) will cause symptoms. I see this 2-3 times per year in my pediatric hospitalist practice.

  • 2014-06-04 | Kyndal

    My son is 4 months was breastfed until 2 months now he is mostly formula. He is on nutramigen but still seems to be getting hive like bumps…reflux issues and seems to be red on his bum from the nasty green poo he has (sorry if tmi) I tried talking to my sons doctor about other formulas and he said other than thr alimentum and nutramigen there was no choice. So what can I do when my sons pedi isn’t aware of the amino acid formula?

  • 2014-06-04 | Rob

    Hi Kyndal,
    We’re sorry to hear that you’ve had a rough few months. It’s not unusual for pediatricians to be less familiar with amino acid-based formulas. You might visit this site for some helpful tips in discussing Neocate with them:
    Good luck! Call us anytime - 800.365.7354.

  • 2014-08-14 | mirella

    My baby was born at 33 weeks. While in the NICU he was on gs 22 cal thru feeding tube seemed to be doing fine at dicharge he started with gs gentle but became severly constipated and bloating and rash. We were changed to alimentum rtf and did well, we did the powder and symptoms got worse he also having excessive secretions and spits up with the powder. What do u recommend

  • 2014-08-15 | Rob McCandlish, RDN

    Hi Mirella,
    The symptoms you describe are all possible symptoms of cow milk allergy, and often don’t show up right away. However other factors could contribute to those symptoms. For some children with cow milk allergy the symptoms resolve with the formulas that you mentioned, but this doesn’t always happen. If they are symptoms of cow milk allergy, then Neocate could help. We can’t provide medical advice, so the best thing to do would be to talk with your child’s healthcare team. Ask the pediatrician, allergist, or gastroenterologist if they recommend a trial of Neocate and, if so, for how long. This site has tips to help discuss that with them:
    Good luck! Call us anytime - 800.365.7354

  • 2014-08-23 | cassandra

    my son is almost 3months old when we left the nicu he was on Enfamil elecare but he started having bloody stools so they said he had a milk protein allergy so they put him on neocate he has been on it for 2 weeks now and seems to have occasional gagging and not wanting to eat like he used to

  • 2014-08-25 | Rob McCandlish, RDN

    Hi Cassandra,
    It’s not unusual for some infants to take a while to adjust to the taste of an amino acid-based formula. You should check with your healthcare team to see if they have any suggestions or concerns. This guide, with tips from a Feeding Specialist, might have some good tips that you could discuss with them:
    Good luck! Call us if you have questions - 800.365.7354

  • 2014-10-20 | Melissa

    My 3 month old son has been of Algmemtin for a month now and he has really bad dry skin/eczame. My daughter when she was born had the milk protein allergy and was put in elecare but she had blood in her stool. Could he have the allergy to and be causing eczame?

  • 2014-10-21 | Rob McCandlish, RDN

    Hi Melissa,
    Yes, your son could have a milk allergy. There’s a pretty strong link between family members: if the first child has an allergy other children are more likely to have a food allergy (compared to families without food allergy.)
    Yes, eczema can be a symptom of cow milk allergy. As your son has been on his current formula for serveral weeks, you may want to check with his healthcare team to see if it would be worth trialing Neocate for 2 weeks. If his eczema is related to cow milk allergy, you’d expect to see an improvement.
    Best of luck!

  • 2014-11-12 | krista

    Hi my son is 9 weeks. We have tried 5 different formulas so far. The similac advanced, alimentum, and nutrimagen all gave him the diahrea a red ring on his butt and his butt was raw you could see flesh. Then we tried similac soy he was ok for a few weeks then he got constipated bad and couldnt go to the bathroom. Now we are trying the similac sensitive, he is still if not worse very gassy, hardly ever poops his stomach makes a bad noise, has a red ring on his butt, has bad acne on his face he burps and has acid come up his throat and he has milk come out his nose and mouth at the same time and cant breathe, he also screams and we cant get him to stop, he eats like every 2 hours i know its soon but seems like hes starving, his eyes water, and he sneezes alot and his doctor said once we tried the alimentum then there was nothig else we can do. Now my son had blood wodk and had potassium in his blood. His sister was lactose intolerant and was on alimentum and did ok. Im lactose intolerant also. I dont think they know about neocate coukd that be an option? They havebt even tried to refer us to a gastro or allergist yet, my daughter saw a gastro though. Please help anyway you cab any advice would help thanks

  • 2014-11-13 | Rob McCandlish, RDN

    Hi Krista,
      We’re sorry to hear that your son (and you) have had such a rough few weeks. We often hear from families who, like you, have been through many formulas with little to no improvement in symptoms. For infants with a cow milk allergy, most might feel better on one of the formulas you mentioned, but many might not fully improve. If your son’s symptoms are due to cow milk allergy, Neocate could help. It would be best to bring this up with his doctor to see if they would recommend trialing Neocate or referring to a specialist. This site has resources that might be helpful in having the conversation with your doctor:
      Best of luck,

  • 2014-11-23 | Yana

    Hi. This might be a late comment? What about hypoallegrneic Elecare there is for infants with dha and for jr. I used it with my 1st and using it with my 2nd. And i read a lot of good reviews….

  • 2014-11-24 | Rob McCandlish, RDN

    Hi Yana,
      The formulas you mentioned are similar to Neocate in that they are made with amino acids. However, they are made on shared equipment with dairy-containing formulas and use soy oil. These are factors that lead some families and clinicians to choose Neocate instead. Aside from this, there are a number of features and services that Neocate offers that other amino acid-based brands do not because at Nutricia we’re focused on specialized medical nutrition.

  • 2015-09-09 | Amy

    We have recently gone from EBF and I had been dairy free for 5 weeks with no improvement. The doctor gave is alimentum to try, however after 2-3 days I always want to go back to nursing because besides a slight decrease in reflux symptoms, he is extremely gassy which wakes him up all
    Through the night and he gets bloated and cannot made a bowel movement without pain and discomfort for 3 days. I always feel like my breast is best, by realize 2 feedings in that I am wrong. I know I haven’t give him time to get used to the alimentum, but I never expected the gassiness and discomfort still. I want to try neocate but I know I should give this a try for a solid week or 2 before we switch. I suspect severe food allergies as it runs in our families, especially my first cousins children. Are these normal for alimentum and should we continue or is this adverse reaction and we should switch? I have a sample in my cupboard, just not sure yet.

  • 2015-09-10 | Nutrition Specialist

    Hi Amy,
      You’ve been through so much - we’re sorry to hear you are still struggling. Since your 5 weeks of no dairy didn’t result in improvement on EBM, some healthcare teams might not expect formulas made from dairy (even broken down dairy) to be successful either. We can’t give you advice about whether or not you should switch to Neocate, but if the healthcare team has given you a sample already they might not be opposed to trying Neocate sooner than after a full week or two on the other formula. Definitely check with the healthcare team for their guidance, though.
      Best of luck,

  • 2015-10-06 | Aviva

    I know that Neocate is soy free, which is wonderful. Why is there no soy and corn free option? My child is very reactive to corn and has not been able to tolerate any elemental. It seems like there should be a soy and corn free option. Is this on the horizon?

  • 2015-10-06 | Nutrition Specialist

    Thanks for your question, Aviva. No plans at this time, though we have been getting more requests for such a formula. We’ll pass this to our product development team. For now, families with a medical need for such a formula have to work with their healthcare teams to create one from scratch using available components, like our Complete Amino Acid Mix.

  • 2016-09-20 | Zoya


    My daughter is 3.5 months and been having very mucousy stool for about 5 weeks now which has been getting worse. We noticed a tiny blood spot in her stool in addition to her having issues sleeping and while asleep at night lifting her legs up time and time again and throwing them down so hard that would wake us up,so i contacted her Dr. I have been on a dairy/soy-free diet and two weeks ago we tested her poop and no sign of blood. The mucous did remain however. I had the stool tested again couple of days ago and they found blood again. I was giving her alimentum powder and my breast milk while on the diet. I then was advised to feed her alimentum RTF and no breastmilk and I have been for the past three days. I still see streaks of blood in her stool but hardly any mucous. What has been upsetting though is how itritated and fussy she has become, crying or screaming almost all day. My question: Is this a possible side effect of alimentum RTF?!!! Thanks.

  • 2016-09-21 | Nutrition Specialist

    Hi Zoya,
      Alimentum RTF is a formula that’s made with extensively hydrolyzed dairy protein. That means the protein comes from milk, but has been broken down into smaller pieces. For many infants with a cow milk allergy this type of formula will fully resolve symptoms. However, for other infants with cow milk allergy, it will only partially resolve symptoms, or may not resolve symptoms at all. For those infants, the next step would be an amino acid-based hypoallergenic formula like Neocate. The next step would be to ask your daughter’s doctor for advice on how long to wait to see if her symptoms improve before trialing a formula like Neocate. Please call us if you have any questions - 800.365.7354 - and best of luck!

  • 2016-09-27 | Zoya

    Thanks Rob.

  • 2017-01-27 | Ellen

    Hi -

    My 3 month old son has been on neocate for a month and has started passing mucous in his stool in the past week. He usually has 1-2 bowel movements a day. I am worried that he started passing mucus (though no blood). He is not congested and is otherwise as is normal. Please advice.

  • 2017-02-02 | Nutrition Specialist

    Hi Ellen,
      Glad to hear that your son seems to be doing well - that’s always good news! The presence of mucus may mean something or nothing at all. We often think of mucus as a symptom of a food allergy, which could suggest that he hasn’t fully improved on Neocate. However, mucus can just be a byproduct of your son’s new “normal” of being on an amino acid-based formula like Neocate, and the impacts it has on the types of bacteria in his gut. We’ve certainly heard that from other Neocate parents. Remember: every little one’s experience is unique!
      The best thing to do is to check with your son’s healthcare team. They may decide to test to see if there is any blood in the stool that is not visible, just to be sure.
      Best of luck!

  • 2017-02-06 | stephanie Harry

    Hi there,
    My daughter has been having bloody stools off and on for 6 months now. We have been on puramino a+ for 1 week now and she is having full bloody tinged diapers versus just strands here and there. Why would this happen on an amino acid based formula? She had been diagnosed with eosinophilic colitis.  Thanks!

  • 2017-02-08 | Nutrition Specialist

    Hi Stephanie,
      Just to be clear, the formula you mentioned is not one that we make. With any change in formula, there can be an adjustment period of up to about 2 weeks. Symptoms in that window of time can be variable. The best thing to do would be to check with your daughter’s doctor to get his or her thoughts.
      With Neocate infant formulas, we test every batch to ensure that there is no dairy protein, and they are made in our dedicated 100% dairy protein-free facility. This virtually eliminates the possibility that there might be trace amounts of dairy protein that could elicit an allergic reaction to cow milk.
      I hope this helps - best of luck to you!

  • 2017-02-12 | Angela harmon

    Hello. My daughter is on elecare atm. Been on it since Jan 11. She still has mucus in poop. And screams when she poops. She is allergic to cow protein. And lactose intolerant.  Highly allergic to soy. I recently discovered elecare has soy oil? She is 2mo. So She has to be on infant formula. Does your company use soy oil in your formula like elecare?

  • 2017-02-13 | Nutrition Specialist

    Hi Angela,
      In the United States, Neocate hypoallergenic infant formulas - Neocate Syneo Infant and Neocate Infant DHA/ARA - are the only ones that do NOT use soy oil. You can read more about that here: http://bit.ly/NoSoyNeocate
      Let us know if you have further questions,

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Food Allergy Living is a resource for parents of children with food allergies, brought to you by Nutricia, the makers of Neocate. For more in-depth information about our purpose & authors, see our About Food Allergy Living page.