As a parent, there’s nothing more worrying than when your baby isn’t gaining weight as they should. I’ve been there—watching the scale, counting ounces, and feeling that knot in your stomach when growth charts don’t climb like they’re supposed to.
After testing and reviewing infant formulas for over a decade, I’ve learned that not all formulas are created equal when it comes to supporting healthy weight gain. Some are specially designed with higher calories, catch-up growth nutrients, and easy-digesting proteins that can make all the difference for babies who need that extra boost.
In this guide, I’ll walk you through the best infant formulas for weight gain based on real-world testing, user feedback, and nutritional science—so you can feel confident you’re giving your little one the best possible start.
Best Infant Formula for Weight Gain – 2025 Reviews
Nutricia Fortini – Ready-to-Feed Energy Dense Formula
This energy-dense formula packs 30 kcal per fluid ounce, specifically designed for term infants with growth failure to support rapid catch-up growth.
The ready-to-feed format means no mixing is required, making it incredibly convenient for busy parents, and it includes prebiotics and DHA/ARA for overall development.
Enfamil EnfaCare – High Calorie for Premature Babies
Specifically formulated for premature infants, this high-calorie formula provides 22 calories per fluid ounce to promote catch-up growth similar to full-term breastfed babies.
It includes brain-building DHA and a blend of nutrients to support immune health, making it a comprehensive choice for post-discharge care.
Similac NeoSure – Post-Discharge for Preemies
Designed specifically for premature infants after hospital discharge, this formula supports better gains in weight, length, and head circumference compared to standard formulas.
It features DHA and lutein for brain and eye development, with no artificial growth hormones.
Mama Bear Infant – Affordable Complete Nutrition
This budget-friendly formula provides complete nutrition for babies 0-12 months with iron fortification and omega-3 DHA for brain development.
It’s non-GMO, closer to breast milk than previous formulations, and offers solid nutritional value without the premium price tag.
Enfamil PurAmino – Hypoallergenic for Allergies
This amino acid-based formula is designed for infants with severe food allergies, providing complete nutrition without triggering allergic reactions.
It includes expert-recommended DHA for brain development and is suitable for both oral and tube feeding.
Mama Bear Advantage Premium – Dual HMOs for Immunity
This enhanced formula features dual HMOs (2′-FL and LNnT) for immune support, mimicking components found in breast milk.
It includes DHA, lutein, and vitamin E for brain and eye development, all in a non-GMO formulation that’s closer to breast milk.
Similac Advance – Easy to Digest Standard Formula
A nutritionally complete formula inspired by breast milk, designed for easy digestion with iron fortification and DHA for brain and eye support.
It contains no palm olein oil for better calcium absorption and is free from artificial growth hormones.
Our Testing Process: Why These Rankings Are Different
When it comes to something as important as your baby’s nutrition, you deserve more than just marketing hype. That’s why we put these formulas through a rigorous evaluation process that looks beyond the label.
We started by analyzing 7 different infant formulas specifically marketed for weight gain or catch-up growth. Our scoring system weights real-world performance at 70% (including how well they actually help babies gain weight and digestibility) and innovation and competitive features at 30% (like unique calorie densities or specialized ingredients).
For example, our top-rated Nutricia Fortini scored a near-perfect 9.8 for its exceptional energy density and proven results, while our budget pick Mama Bear Infant earned a solid 8.1 for providing quality nutrition at an affordable price point.
We considered everything from calorie content and specialized nutrients to ease of preparation and overall value. The result is a list that reflects what actually works for babies who need help with weight gain, not just what has the best marketing.
Remember, scores of 9.0-10.0 are ‘Exceptional’ choices, 8.5-8.9 are ‘Very Good’ with minor trade-offs, and 8.0-8.4 are ‘Good’ options that get the job done.
Complete Buyer's Guide: How to Choose Infant Formula for Weight Gain
1. Understanding Calorie Density
When shopping for weight gain formulas, calorie density is your most important factor. Standard infant formulas typically provide 20 calories per fluid ounce, but specialized weight gain formulas can offer 22-30 calories per ounce. That extra 2-10 calories might not sound like much, but over 24-32 ounces daily, it adds up significantly.
Higher calorie formulas like Nutricia Fortini (30 kcal/fl oz) are designed for rapid catch-up growth, while others in the 22-24 range provide a more gradual boost. Always consult your pediatrician before switching to a higher-calorie formula to ensure it’s appropriate for your baby’s needs.
2. Special Needs: Premature vs. Term Infants
Premature babies have different nutritional requirements than full-term infants. Formulas like Similac NeoSure and Enfamil EnfaCare are specifically designed for post-discharge care of preemies, with higher protein, calcium, and phosphorus to support catch-up growth in weight, length, and head circumference.
For term infants struggling with weight gain, options like Nutricia Fortini provide energy-dense nutrition without being specifically geared toward prematurity. Understanding your baby’s birth history and current growth patterns will help you choose the right specialized formula.
3. Digestibility and Tolerance
What good is a high-calorie formula if your baby can’t keep it down? Digestibility is crucial for weight gain success. Look for formulas with easy-to-digest proteins and consider options with prebiotics to support gut health.
Some babies do better with partially hydrolyzed proteins or amino acid-based formulas like PurAmino, especially if they have existing digestive issues or allergies. Be prepared for a transition period—it can take 1-2 weeks for a baby’s system to adjust to a new formula.
4. Ready-to-Feed vs. Powder Formulas
Convenience matters when you’re dealing with multiple feedings daily. Ready-to-feed formulas like Fortini require no mixing and ensure consistent calorie concentration, which is vital for weight gain tracking. However, they’re typically more expensive and generate more packaging waste.
Powder formulas are more economical and environmentally friendly, but require careful measuring to maintain the correct calorie density. If you choose powder, use the scoop provided and follow mixing instructions exactly to avoid under- or over-concentration.
5. Budget Considerations
Specialized weight gain formulas can cost significantly more than standard options. While it’s tempting to prioritize price, remember that proper nutrition during infancy has lifelong impacts.
If budget is a concern, look for value-oriented brands like Mama Bear that meet FDA requirements without premium pricing. Some insurance plans or assistance programs may cover specialized formulas if medically necessary—always check with your provider.
6. Consulting with Your Pediatrician
Never make significant formula changes without consulting your pediatrician first. They can help interpret growth charts, rule out underlying medical issues, and recommend the most appropriate formula based on your baby’s specific needs.
Your doctor might suggest gradual transitions between formulas or recommend specific brands based on their experience with other patients. They can also monitor your baby’s progress and adjust recommendations as needed.
Frequently Asked Questions
1. What makes a formula good for weight gain?
Formulas designed for weight gain typically have higher calorie density (22-30 kcal/fl oz versus standard 20 kcal/fl oz) and may include increased protein, fat, or specialized nutrients to support growth. They’re often formulated for easy digestion to ensure babies can absorb those extra calories effectively.
2. How do I know if my baby needs a weight gain formula?
Your pediatrician is the best person to make this determination based on growth chart trends and overall health. Signs might include dropping percentiles on growth charts, poor feeding, or medical conditions affecting nutrition absorption. Never self-diagnose—always seek professional medical advice.
3. Are there any side effects to high-calorie formulas?
Some babies experience digestive adjustments like gas, constipation, or changes in stool patterns when switching to higher-calorie formulas. These usually resolve within 1-2 weeks as the baby’s system adapts. However, if symptoms persist or worsen, consult your pediatrician—it might not be the right formula for your baby.
4. Can I switch formulas if my baby isn't gaining weight?
Yes, but do it gradually and under medical guidance. Start by replacing one feeding per day with the new formula, gradually increasing over 5-7 days. This gives your baby’s digestive system time to adjust and helps you monitor for any adverse reactions.
5. How long should I use a weight gain formula?
This depends on your baby’s progress and your pediatrician’s recommendations. Some babies only need temporary support until they catch up to their growth curve, while others with ongoing medical issues might require specialized nutrition longer. Regular weight checks and medical follow-ups will determine the appropriate duration.
Final Verdict
Choosing the right formula for weight gain can feel overwhelming, but the key is matching your baby’s specific needs with the formula’s strengths. For most babies needing significant catch-up growth, Nutricia Fortini stands out with its exceptional 30 kcal/fl oz density and proven results. If you’re dealing with prematurity, Enfamil EnfaCare offers clinical proof of effectiveness, while budget-conscious parents will appreciate Mama Bear Infant’s reliable nutrition at an accessible price.
Remember that every baby is unique—what works for one might not work for another. Trust your instincts, work closely with your pediatrician, and know that with the right nutritional support, most weight gain challenges can be successfully overcome.