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Similac® Soy Isomil®

Complete nutrition for sensitive tummies

Fussiness and gas can be a common part of feeding your baby.

Similac Soy Isomil is specially designed to comfort with the gentleness of soy to soothe the tummy.

Soy-based formulas have been clinically shown to help reduce feeding problems. No other soy-based formula has been studied more than Isomil.

Has OptiGRO to support your baby's brain and eye development.

If your baby’s fussiness or gas seems excessive, ask your physician about switching to Similac Soy Isomil.

Soy formulas are not recommended for premature infants with birth weights of less than 1800 g.

Similac Soy Isomil formula product for infants

Available In:

1.45-lb Powder

12.4-oz Powder

1-qt Ready to Feed

Soy for fussiness and gas

Nutrition Information

Powder / 1.45 lb

Serving size: 100 Cal (prepared as directed)*

Amount per serving

  • Calories:


  • Volume, mL:


  • Protein, g:


  • Fat, g:


  • Carbohydrate, g:


  • Water, g:


  • Linoleic Acid, mg:


Vitamins & Minerals

* Nutrient values are applicable when prepared as directed.

Similac® Soy Isomil®
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Similac Soy Isomil Reviews

Rated 4 out of 5 by from This product has been so helpful My guy couldn’t tolerate anything else so this is the product we have been using for the past 5 months. Before this he was always throwing up, gassy, and constipated but he’s now 8 months old and started out a 4lb preemie and is now a 19lb 8 month old. I still receive Neosure coupons for the Strong Moms rewards but I can’t use them.
Date published: 2018-05-24
Rated 1 out of 5 by from this formula didn’t settle well with my son my 3 week old ended up with bloody stool, so his pediatrician said he had a milk allergy. his doctor changed his formula to Enfamil Prosobee which ended up settling great with his tummy and saw a changed in his stool the same day. for financial reasons the pediatrician had to change formula from Enfamil to Similac Isomil, thinking it would work exactly the same because both formulas are soy based, and i was very wrong. this formula led my son to have even more watery stool than with the original milk based formula. i was very disappointed i have to return to the doctor to get my sons formula changed once again.
Date published: 2018-04-15
Rated 2 out of 5 by from This product casued my son constipation all the time. We have been through almost all the formula Similac has to offer soy was our last option. My son did the worst by far on the soy it caused him severe constipation and discomfort and he would still be spitting up a lot 2 hours after he ate . He was also on the pro advance and he spit up a lot on that so we switched him to the pro sensitive and he spit up a lot and it was always chunky. We also tried the spit up and it was to thick for him to get out of his bottle. We switched back to the pro advance because he seems to do the best on it.
Date published: 2018-03-30
Rated 3 out of 5 by from Hoping This Eventually Works We are now on our FOURTH formula in our daughters short three months! We started with Enfamil Newborn from the hospital, that ended up giving her horrible gas pains nonstop. We switched to Enfamil Gentlease, it got better then worse again. So we switched to Smililac Pro-Sensitive it again got better then WAY worse and she was having diarrhea that turned to constipation. We are now using the Similac Soy. It is starting to possibly make a difference but she still has pretty bad gas pains. We say a GI doctor and she put her on a laxative but I really don't want to have to use it. She said soy is very binding. She no longer has diarrhea but her gas pains are still there. Hoping the soy will continue to make a difference or we will unfortunately, once again, will be on the hunt for a new formula. :(
Date published: 2018-03-20
Rated 5 out of 5 by from This product has helped my baby. My 3 month old has been suffering from eczema. She has had dry patches of skin all over her little body. The blotches were getting worse and we couldn't figure out what was going on. We switched creams, bath products and detergent. So we figured it had to be internal. On a bunch, I switched her to the Similac Soy hoping she had a milk allergy and bingo! It's only been a few days and her skin is clearing up wonderfully. The poor thing would tear her skin up itching it all night and finally she has some relief. Thank you Similiac.
Date published: 2018-03-12
Rated 5 out of 5 by from Solved all my problems! My poor baby girl was so fussy with all formula after we switched her from breast milk (couldn’t make enough). Poor little girl would scream for hours with the worst gas. Started the soy formula at 2 weeks & we saw a change in her within the first 24hrs! Thank you!
Date published: 2018-02-07
Rated 5 out of 5 by from LIFESAVER! My baby was breast fed only until she was about 2 and a half months old...had trouble with milk flow so I had to start supplementing, started with PRO-sensitive but she started screaming 24/7! She was not herself, crying so hard and stiffing her body so bad and not sleeping, switched to this soy, now she is such a happy baby and sleeps ALL NIGHT!!!!!! Thank you Similac!!!!!! You have saved us with this formula!!!!
Date published: 2018-01-26
Rated 5 out of 5 by from love it ! I have a whole new baby ! we tried 2 different formulas and she still had the fussiness and gas. withing 24 hours of using the soy she was a brand new happy baby !
Date published: 2018-01-05
Rated 5 out of 5 by from Works for us My DS has a milk intolerance. Breast milk and regular formula would mess with him so bad. He has been so much better since switching to soy
Date published: 2018-01-05
Rated 4 out of 5 by from Happier baby 3mo old exclusive human milk up until 3 wks ago. Started to cry all the time and baby's' stomach was hard. Switched to regular formula but the fussiness continued. finally 10 days ago saw her pediatrician who suggested a milk allergy and to try soy formula. I stopped dairy products and would nurse occasionally but baby mainly ate soy formula. Much better, not as fussy and is able to nap better. My concern is her stool is black like. breast milk its seedy musty yellow. With regular formula its more dense gray like. But this is runny black. none of the other reviews mentioned anything about stool color.
Date published: 2017-12-13
Rated 5 out of 5 by from 6 months old and now so much happier! My daughter was breastfeed from nb-3 months but due to a slight younger tie started in formula. She was on a regular formula and her poor tummy was so bad. She had horrible diapers and screamed 75% of the day. At her 6 mo th check up the dr have us a sample of Soy Similac. We immediately started her on it and saw a change almost immediately. She could sit still longer, she was happy, and didn’t clear a room! Ty!
Date published: 2017-11-28
Rated 5 out of 5 by from Sanity Saver My breast milk came in late because she was born early so we exclusively use formula. We started out on newborn but she was colicky so we switched to sensitive. She was still colicky so our pedi advised us to try Soy and within a day she was a totally different baby. Didn't cry for hours on end and didn't spit up half of her dinner :)
Date published: 2017-11-17
Rated 5 out of 5 by from Who is this perfect 4 month old and what have you done with my baby??? As a new mother I thought the gas pains fussiness and runny stools we're all just a normal part of early infancy for my daughter. I didn't have anything to compare her experience too. A friend of mine who is a retired registered nurse noticed that her symptoms were not in the ordinary and pointed it out to me. After some research we decided to try her out on just soy Isomil. Lactose intolerance never occurred to me. We started the soy as opposed to the Similac Advance and within 48 hours it was like she was a completely different baby. Her stools now look healthy and firm, she's never fussy unless she absolutely need something like a bottle or a diapering, and although I still give her gas drops for the occasional gas pains those have diminished substantially. I'm so glad we tried her on the soy Isomil and took that chance. It has changed her life and made the quality of everything much better.
Date published: 2017-11-13
Rated 5 out of 5 by from Total lifesaver My breastmilk didn’t come in so we had to use formula. The hospital gave us Similac Advanced Sensitive but my little one developed a wicked case of colic. So we changed to another brand at the peditrician’s recommendation. It helped some but she still suffered from painful excess gas. So we’re trying the Similac soy and what a lifesaver! My sweet girl is happier now & so much less fussy!
Date published: 2017-11-11
Rated 5 out of 5 by from Milk allergy My baby has a milk protein allergy and this is the only formula that helped her. She gained a lot of weight as well. This formula worked wonders for her, and would recommend it to alot of mothers, so they didnt have to experience what I have is scary...
Date published: 2017-11-09
Rated 4 out of 5 by from It is amazing Only thing my little girl can eat i absoulty love it!
Date published: 2017-11-01
Rated 5 out of 5 by from works Wonders This product works wonders on my one month old daughter! She had excessive spitting up with each bottle on similac advanced but after switching her to similac soy she doesn’t spit up! Had worked wonders on her :)
Date published: 2017-10-30
Rated 5 out of 5 by from Very helpful We started supplimenting with formula for my son at 5 days old. We tried the Pro-Advanced formula, but we soon discovered that with that aND breastmilk, he has awful reacoons to dairy. After cutting dairy and switching him to the Isamil formula and had no other problems so far. We had also used this formula for our other two children when they were infants with great results! It's a really great formula for infants with dairy problems.
Date published: 2017-10-28
Rated 5 out of 5 by from Amazing This formula helped tremendously. She went from constipated, fussy, and gassy to a happy healthy baby within 10 hours
Date published: 2017-10-18
Rated 5 out of 5 by from Very helpful for my son's twin boys I had always given my children soy formula after breastfeeding for a couple of months due to the amount of allergies in our families. It was the best formula for them. When my son & his wife recently had twins she decided to breastfeed and give formula to supplement. They tried one brand and then switched to Similac Pro Sensitive, but there were some issues. The twins were continuously spitting up and sometimes it would be chunky. From the beginning I had suggested they try the soy formula.They just turned 3 months and they finally decided to go with my suggestion. What a huge difference it has made with the babies. Less fussiness and way less spitting up. I think they wish they had taken my advice from the beginning.
Date published: 2017-10-08
Rated 5 out of 5 by from Only Formula we could use This is by far the best formula out there!
Date published: 2017-10-02
Rated 5 out of 5 by from Breast feeding life saver! My sweet little angel is 16 days old today. After a whole week of exclusively breast feeding and no sleep we figured out she has a dairy sensitivity. I've had to cut out all dairy from my diet to be able to continue feeding her partially. Similac soy has made it possible for me to feed her while my body is cleansing from all the dairy and is gentle enough for her to finally be able to sleep. We could not be happier with the results and the product.
Date published: 2017-09-30
Rated 4 out of 5 by from This product helped my baby We started off with regular similar formula but quickly learned our little princess has a lactose intolerance and switched to soy. It took over a week to finally get adjusted with her stool back to normal, less fussiness and trapped gas. But I’m so glad we figured the problem out so quickly and was able to fix it.
Date published: 2017-09-29
Rated 5 out of 5 by from Gentle on Baby's Stomach We tried all the samples our doctor gave us including the other brands, but found our baby has some milk sensitivity and switched to soy. She spits up less than before, and her fussiness is in check! My friend recommended it and I'm glad she did!
Date published: 2017-09-27
Rated 3 out of 5 by from This product is very good, but.... This product seems to be working as far as the frequent spiting up. However, every time I give my grandson a bottle, he has runny stool. What should I do?
Date published: 2017-09-22
Rated 5 out of 5 by from It is AMAZING. After, trying several different ones. This one is the ONLY one that been great. No spit up and NO diarrhea. GREAT PRODUCT! After trying several different Similac's and several different Geber and Enfamil. Similac Soy is amazing. She immediately started to feel better. She doesn't spit up at all and she doesn't have diarrhea at all like she was with all the rest. Similac has always been my brand but, I didnt know what to do when she couldn't keep down the Advance or the Sensitive.
Date published: 2017-09-18
Rated 5 out of 5 by from Love it Helped my twins with their reflux problems!
Date published: 2017-09-17
Rated 5 out of 5 by from Love this! We love the similac soy formula for our baby's sensitive belly!
Date published: 2017-09-09
Rated 5 out of 5 by from We love Similac! We started our new baby girl on Similac Advance but she was fussy and crying all the time, so we switched to Similac Soy Isomil and it was a godsend. She has been a completely different baby since we switched. She is such a happy baby & I am so thankful for Similac.
Date published: 2017-09-06
Rated 5 out of 5 by from I love it. When i had my son i strictly wanted to breast feed but after a while i started noticing that he would puke everything up with in minutes of being done eating or he would be so constipated he would scream in pain. No matter what i did to my diet nothing worked. Well our doctor found out he was lactose intolerant and allergic to my breast milk so the recommended that we try soy. Ever since i started him on soy formula he has been able to eat more and go better. Just wish i could by bulk in the similac formula he goes through a can of the powder ever 3 days and goes through the premade bottles every day . He eats so much of it.
Date published: 2017-08-28
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Has your family been affected by Hurricane Michael?

If you or someone you know has been affected, find out how Similac® can help.