Similac Sensitive vs. Enfamil Gentlease

If your baby is fussy and gassy, your pediatrician or a well-meaning relative has probably suggested switching to a "gentle" formula. Similac Sensitive and Enfamil Gentlease are the two most popular options — but they work differently, and understanding the difference matters.

Similac Sensitive reduces lactose, replacing most of it with corn maltodextrin. It is designed for babies with lactose sensitivity (difficulty digesting milk sugar). Enfamil Gentlease uses partially hydrolyzed proteins — the milk proteins are partially broken down to make them easier to digest. It targets protein digestion issues rather than lactose sensitivity.

Here is the critical context: true lactose intolerance in infants is extremely rare. Most newborn fussiness and gas is normal — immature digestive systems producing gas as they learn to process any food. Switching formulas may or may not help, and the improvement often coincides with natural digestive maturation rather than the formula change itself.

Give any formula switch at least 1–2 weeks before evaluating. For more on feeding basics, see our baby feeding chart.

The core difference is what each formula changes from the standard version.

Protein: intact vs. partially hydrolyzed

Enfamil Gentlease uses partially hydrolyzed nonfat milk and whey protein. "Partially hydrolyzed" means the proteins are broken into smaller fragments, which may be easier for some babies to digest. This is different from extensively hydrolyzed protein (used in hypoallergenic formulas like Nutramigen or Alimentum) — partially hydrolyzed proteins still contain larger protein fragments and are NOT suitable for confirmed cow's milk protein allergy.

Similac Sensitive uses intact milk protein isolate — the protein is not broken down. If protein digestion is your baby's issue, Gentlease's approach addresses it more directly.

Carbohydrates: corn maltodextrin vs. corn syrup solids

Both formulas replace most lactose with corn-derived carbohydrates. Similac Sensitive uses corn maltodextrin. Enfamil Gentlease uses corn syrup solids. Despite the alarming name, corn syrup solids in formula are not the same as high-fructose corn syrup — they are a glucose polymer used as a carbohydrate source. Both serve the same function: providing calories without lactose.

The EU does not permit corn syrup solids as the primary carbohydrate in infant formula. If this matters to you, neither of these formulas meets that preference — you would need to look at European formulas or standard lactose-based formulas instead.

Fat source: palm olein again

Similac Sensitive does not use palm olein. Enfamil Gentlease does. If your baby is already constipated and fussy, the palm olein difference may compound the issue. Switching to Similac Sensitive addresses both lactose sensitivity and palm olein exposure.

Neither brand will tell you the most important thing: most newborn fussiness resolves on its own between 6 and 12 weeks, regardless of formula changes. The "improvement" many parents see after switching to a gentle formula often coincides with natural digestive maturation.

A 2018 study in the Journal of Pediatrics found that formula switching did not improve outcomes for most fussy babies. The AAP recommends giving any formula at least 2 weeks before switching, and consulting a pediatrician if symptoms persist.

Both Similac Sensitive and Enfamil Gentlease use corn-derived carbohydrates as their primary sugar source. If you switched to a gentle formula specifically to avoid "bad ingredients," you may be surprised to find corn syrup solids or maltodextrin on the label. These are safe and well-studied, but they are worth knowing about.

Store-brand gentle formulas exist and meet the same FDA requirements. Parent's Choice Sensitivity and Up & Up Sensitivity are available at Walmart and Target respectively, at 30–40% less per ounce.

Taste: Both taste different from standard formula. Gentlease has a slightly bitter taste due to the hydrolyzed protein. Similac Sensitive is slightly sweeter. Some babies accept one more readily than the other.

Mixing: Both dissolve reasonably well. Gentlease can be slightly foamier due to the hydrolyzed protein. Let the bottle settle or use a formula pitcher.

Stool changes: Expect stool changes with either formula. Reduced lactose formulas may produce looser stools. Partially hydrolyzed formulas may produce greenish stools. Both are normal and not cause for concern.

Availability: Both are widely available at every major retailer. Neither requires specialty ordering.

Gentle formulas are for mild fussiness and gas — not for true allergy or intolerance. If your baby's symptoms are severe or do not improve after 2 weeks on a gentle formula, talk to your pediatrician about hypoallergenic options.

Similac Sensitive and Enfamil Gentlease address fussiness through different mechanisms. Similac Sensitive targets lactose sensitivity. Enfamil Gentlease targets protein digestion. Neither is hypoallergenic.

Choose Similac Sensitive if: you suspect lactose is the issue, you prefer a palm-olein-free formula, or your baby tends toward constipation.

Choose Enfamil Gentlease if: you suspect protein digestion is the issue, your baby does well with the standard Enfamil line, or your pediatrician specifically recommended it.

Important context: most newborn fussiness resolves on its own by 3 months. If a gentle formula does not help after 2 weeks, do not keep switching — talk to your pediatrician about next steps, which may include a hypoallergenic formula.

If you are switching formulas, tracking feeds and symptoms (gas, spit-up, fussiness, stool changes) for 1–2 weeks gives you and your pediatrician a clear picture. tinylog makes this easy — a few taps per feed.

For hypoallergenic options, see Alimentum vs. Nutramigen vs. PurAmino. For the standard formula comparison, see Enfamil vs. Similac. For constipation-specific guidance, see best formula for constipation.

• Gentlease vs. Sensitive — Same comparison, different angle
• Best Formula for Gassy Babies — What actually helps
• Enfamil vs. Similac — A complete comparison

• U.S. Food and Drug Administration. "21 CFR Part 107 — Infant Formula." Code of Federal Regulations.
• American Academy of Pediatrics. "Choosing an Infant Formula." HealthyChildren.org, 2024.
• Iacovou M, et al. "Randomised clinical trial: reducing the intake of cow's milk protein in infants." Journal of Pediatrics, 2018.
• Koo WW, et al. "Palm olein in infant formula affects bone mineralization and calcium absorption." Journal of the American College of Nutrition, 2006.
• Vandenplas Y, et al. "Guidelines for the diagnosis and management of cow's milk protein allergy in infants." Archives of Disease in Childhood, 2007.
• U.S. FDA. "Infant Formula Guidance Documents and Regulatory Information." fda.gov, 2023.

This guide is for informational purposes only and is not a substitute for professional medical advice. Formula recommendations should be discussed with your pediatrician, especially for babies with allergies, reflux, or other medical conditions.