I have migrated this post over because I still get emails from parents that had the same issues and didn’t know where to turn. Hopefully it helps provide some insight into transitioning off of a hypoallergenic formula. I’m sure it has some relevance to transitioning between any formulas too.

Definitely consult with your pediatrician prior to making any changes to their diet, especially with kids that have sensitivities or allergies. A pediatric gastroenterologist is also a good resource to help sort things out because it can be a tricky and potentially dangerous endeavor with today’s food allergies and intolerances.


My oldest child was put on Nutramigen hypoallergenic formula when he was about 3 weeks old due to his unrelenting colic. At our 4 month appointment the pediatrician suggested that it was time to start weaning him off. This is something that I was terrified of doing because I felt like it was going to ruin how far we had come since the “colic days”. I didn’t want to do ANYTHING that could send us back to nightmare land! But obviously the kid couldn’t live on hypoallergenic food his entire life so at some point we’d have to tackle the issue.

After our appointment we went home and decided to start the process. We mixed his bottle with 3 scoops of Nutramigen to a half of a scoop of Gentlease formula. Everything was fine until a couple hours later when he projectile vomitted like the exorcist across the room. No seriously! I have never seen anything like it in my life, he shot puke 7 feet across the room, out of his nose and mouth repeatedly for about 3 minutes!! I don’t even know where all of this liquid came from, it soaked the dogs who were laying on the floor below him, it soaked the rug, it covered the wood floors. It scared the crap out of me! Then he proceeded to scream for 45 minutes until he passed out. We continued with the mixed bottles for 3 days and it was a nightmare, he continued to scream for these 3 days. Surprise surprise it was like we were right back in the midst of the colic. So I pulled the plug, enough!

I was torn with what to do, was his body going to have to build up a tolerance? If so we’d have to suck it up and deal with it until he adjusted. OR perhaps until his body was ready it would do us no good to keep torturing the kid because it wouldn’t work until he was ready. Which one? I had no idea.

So I headed back to the pedi and asked him and he shared with me some info that would’ve been nice to know at the previous appointment! Here’s what he told me in simple non-medical terms.

The stomach lining has fingers on one side where the food comes in contact and on the other side is the blood stream. In babies like mine and others with sensitivities the problem is within the lining. The lining isn’t fully meshed and woven together yet so that means when they eat, the milk proteins seep through the gaps in the lining and come in contact with the bloodstream. Think of it as a tightly woven knit fabric versus a crocheted blanket, one has a lot more large holes than the other. Kids with developed gut linings are the former, kids with sensitivities are the latter.

There are things in the bloodstream that think the milk protein is a foreign invader and therefore they attack it. This is what causes the discomfort, pain, and problems with the baby, because the body is attacking the food. So what that means is that until the lining fully grows together with NO gaps the baby will continue to have the same reaction, the body will continue to attack the food, the milk protein.

What this means for us is that we have to wait it out, there’s no telling how long it will take for his stomach lining to fully develop, it’s trial and error. So we were told to go back to regular Nutramigen again for another 2 months and then try again, if he has a reaction then we go back to the Nutramigen for another 2 months and try again, etc. We keep doing this until he has no reaction which means that his stomach has now fully developed.

I asked the pedi if my little guy would still be fussy when we finally switch over and he said that you really shouldn’t notice any change in him with the switch IF his body truly is ready. So if you’re out there trying to wean your baby keep that in mind, if they’re crying and reacting negatively to the switch that means that they are NOT ready, their body isn’t ready yet and no amount of trying is going to help. You just have to wait it out.

He also warned us not to switch too frequently, that’s why he said to wait for 2 months before trying again. Because what happens is those things in the blood that attack the milk protein have a memory and if you allow them to attack the food enough times they will end up ALWAYS attacking it and this can result in an adult that can’t have milk protein, they’re lactose intolerant, etc.

Hopefully that helps some of you in the same boat, at least give you some info and background.

UPDATE: We were able to finally successfully wean him at about 10 months. We tried again at 6 months and it was the same bad reaction, I wasn’t sure if this was from the introduction of real food or whether it was the formula, we decided to err on the side of caution and keep at least one variable controlled so we went back to the Nutramigen. Tried again at 8 months and while this was an improvement you could still tell that something just wasn’t right based on his demeanor, appetite, and stools. 10 months was it and he did fine, we transitioned completely by slowly increasing the amount of Gentlease formula into the Nutramigen bottles over the course of 2-3 weeks. Starting with 1 scoop, upping the ratio finally to half and half, then 3:1 ratio, etc.

The next hurdle was transitioning to regular milk at 1 year old. I was super apprehensive about this too, considering we had just finally been able to switch formulas the month prior. We started slowly with the regular milk (whole Vit. D) a little taste, an ounce, 2 ounces, etc. Shockingly there was NO reaction. Nothing. Within one week he was able to drink exclusively regular milk.

There are some tips from Nutramigen on weaning over here

and here