Enfamil ProSobee vs ByHeart Formula (2026): Which Formula Is Better?
A dairy-free soy formula vs a premium whole-protein cow's milk formula — only comparable if your baby can tolerate both protein types.
By TeachToddler Editorial Team · Updated April 11, 2026 · Formula Comparison
Why This Comparison Matters
Enfamil ProSobee (~$25/12.9 oz) and ByHeart (~$36/24 oz) use fundamentally different protein sources. ProSobee is a 100% soy-based, completely dairy-free formula designed for babies who cannot tolerate cow's milk. ByHeart is a premium cow's milk formula that uses minimally processed whole protein, retaining naturally occurring components like lactoferrin and MFGM that most formulas strip out during manufacturing. These formulas solve different problems — this comparison helps you understand which problem your baby actually has.
- ProSobee: Soy protein isolate, corn syrup solids, zero dairy, DHA/ARA — built for dairy avoidance (mild CMPA, galactosemia, lactose intolerance, vegan families)
- ByHeart: Minimally processed cow's milk with retained lactoferrin, organic lactose, proprietary fat blend, clinically trialed — built for optimal nutrition in dairy-tolerant babies
- Price per ounce: ProSobee at ~$1.94/oz is actually more expensive per ounce than ByHeart at ~$1.50/oz, despite the lower sticker price (ProSobee's can is much smaller)
- The core question: Does your baby need to avoid dairy? If yes, ProSobee. If your baby tolerates dairy and you want a research-backed premium formula, ByHeart
Important: ProSobee solves a specific medical problem — dairy avoidance. ByHeart solves a different one — delivering breast milk-like nutrition from cow's milk. If your baby tolerates dairy, ByHeart offers a meaningfully more advanced nutritional profile. If dairy is the problem, ByHeart's premium features are irrelevant because your baby can't drink it.
Protein: Soy Isolate vs Whole Cow's Milk
The protein story reveals the biggest functional and nutritional gap between these formulas.
- ProSobee protein: Soy protein isolate — concentrated plant protein extracted from soybeans at 90%+ purity. Supplemented with L-methionine to compensate for soy's lower methionine content compared to dairy. Contains isoflavones (phytoestrogens) that the AAP has confirmed safe for full-term infants
- ByHeart protein: Whole cow's milk protein processed using gentle, low-heat methods that preserve naturally occurring lactoferrin — an iron-binding protein found in breast milk that supports iron absorption and has antimicrobial properties. Most formula manufacturing destroys lactoferrin through high-heat processing; ByHeart is one of the few brands that retains it
- Whey-to-casein ratio: ByHeart maintains a proprietary whey-to-casein ratio designed to mimic breast milk (approximately 60:40). ProSobee doesn't have whey or casein — soy protein isolate is a single-source plant protein with its own amino acid profile
- Lactoferrin advantage: ByHeart's retained lactoferrin is clinically significant — lactoferrin enhances iron absorption (reducing constipation from iron supplementation), has direct antimicrobial activity against pathogenic bacteria, and supports immune development. ProSobee, being dairy-free, cannot contain lactoferrin
Carbohydrate Sources
The carbohydrate approach reveals each formula's design philosophy — medical functionality vs breast milk mimicry.
- ProSobee: Corn syrup solids (glucose polymers) as the sole carbohydrate. Completely lactose-free. Corn syrup solids are easily digestible and provide quick energy, but they're sweeter than lactose and lack the prebiotic benefits that lactose provides to the infant gut microbiome
- ByHeart: Organic lactose as the primary carbohydrate — sourced to match breast milk's primary sugar. Lactose promotes calcium absorption, supports Bifidobacterium growth in the gut, and has a lower glycemic index than corn-based sugars. ByHeart does not use any corn syrup, maltodextrin, or glucose syrup
- Gut microbiome impact: Lactose-fed infants consistently develop higher levels of beneficial Bifidobacteria compared to infants fed corn syrup-based formulas. This microbiome difference may have implications for immune development, though long-term outcomes are still being studied
- For lactose-intolerant babies: If your baby has galactosemia or confirmed lactose intolerance, ProSobee's lactose-free formulation is necessary. ByHeart's lactose-rich formula would cause bloating, gas, and diarrhea in these babies
Fat Composition & Brain Development Nutrients
ByHeart takes a notably different approach to fat sourcing that has measurable implications for brain development support.
- ProSobee fats: Palm olein, soy oil, coconut oil, and high-oleic sunflower oil. DHA from algal oil, ARA from fungal oil. The palm olein content has been associated in studies with slightly harder stools and reduced calcium absorption, and the soy oil adds additional omega-6 fatty acids
- ByHeart fats: A proprietary organic fat blend designed to replicate breast milk's fat profile. Includes milk fat (providing MFGM — milk fat globule membrane) along with plant oils. No palm oil. DHA levels are set to match what clinical research suggests is optimal for neurodevelopment
- MFGM (milk fat globule membrane): ByHeart's whole-milk processing retains MFGM — a complex of phospholipids, sphingomyelin, and gangliosides that surrounds fat droplets in breast milk. Randomized controlled trials have shown MFGM supplementation improves cognitive development scores and reduces ear and respiratory infections in formula-fed infants
- ByHeart's clinical trial: ByHeart is one of very few formula companies to conduct its own randomized clinical feeding trial before launch. Their study demonstrated that ByHeart-fed infants had softer stools and less gas compared to infants on a leading cow's milk formula, with equivalent growth outcomes
ByHeart's Differentiator: ByHeart conducted a prospective, randomized clinical feeding trial — something almost no US infant formula brand does. Their results showed comparable growth to established formulas with improvements in stool softness (closer to breastfed infants) and reduced gas/fussiness. Combined with retained lactoferrin and MFGM, ByHeart's science-backed approach is genuinely distinctive among premium formulas.
Gut Health & Immune Function
The gut health profiles of these formulas differ substantially, reflecting the inherent properties of their protein and carbohydrate sources.
- ByHeart gut support: Lactoferrin has direct antimicrobial properties — it binds iron that pathogenic bacteria need to grow (starving them) and can directly disrupt bacterial cell membranes. Combined with lactose feeding beneficial Bifidobacteria and MFGM supporting gut barrier integrity, ByHeart offers a multi-layered gut health approach
- ProSobee gut support: ProSobee does not include added prebiotics, probiotics, or immune-active proteins. Soy-based formulas produce a different gut microbiome profile than cow's milk formulas — typically with fewer Bifidobacteria and more Clostridium species. While clinically adequate, this is a less diverse microbial profile
- Iron absorption: ProSobee is iron-fortified at levels higher than cow's milk formulas to compensate for phytates in soy protein that reduce iron bioavailability by 20–40%. ByHeart's lactoferrin naturally enhances iron absorption, meaning the added iron is more efficiently used
- Stool patterns: ProSobee tends to produce firmer, more formed stools (influenced by soy protein and palm olein). ByHeart's clinical trial data shows softer, more breast milk-like stools — a practical benefit for parents dealing with constipation concerns
Price, Availability & Daily Logistics
Real-world factors like cost, access, and preparation affect which formula families can sustain month after month.
- ProSobee cost: ~$25 for 12.9 oz (~$1.94/oz). Monthly cost: approximately $150–$180. Available at virtually every US pharmacy, grocery store, Walmart, Target, and Amazon
- ByHeart cost: ~$36 for 24 oz (~$1.50/oz). Monthly cost: approximately $130–$160. Available direct from byheart.com (subscription saves ~15%), Amazon, Target, and Walmart. ByHeart's subscription model provides reliable monthly delivery
- Counter-intuitive pricing: Despite the higher sticker price, ByHeart is cheaper per ounce ($1.50 vs $1.94) because ProSobee comes in a much smaller can. Over a month, ByHeart can actually cost less than ProSobee depending on consumption rates
- Taste and acceptance: ProSobee has a distinct soy flavor and faint beany smell. ByHeart tastes mild and creamy with a clean milk flavor. Most babies accept ByHeart easily; some babies need a transition period to accept ProSobee's taste
- Mixing: Both dissolve well. ProSobee can produce some foam when shaken vigorously — swirling instead of shaking reduces this. ByHeart mixes cleanly with minimal frothing
Which Formula Should You Choose?
Your baby's dairy tolerance status is the only thing that matters for this decision.
- Choose ProSobee if: Your baby has a confirmed mild cow's milk protein sensitivity (with pediatrician approval), galactosemia, primary lactose intolerance, or your family requires strictly dairy-free feeding. ProSobee provides complete plant-based infant nutrition that the AAP has confirmed supports normal growth in full-term infants
- Choose ByHeart if: Your baby tolerates cow's milk and you want a clinically trialed, science-forward formula with retained lactoferrin, MFGM, organic lactose, and a breast milk-modeled protein ratio. ByHeart represents the current frontier of premium cow's milk formula design
- Do NOT choose ProSobee if: Your baby has a soy allergy, is premature (AAP advises against soy for preterm infants due to mineral absorption concerns), or has severe CMPA (10–14% cross-react with soy — use a hydrolyzed formula instead)
- Do NOT choose ByHeart if: Your baby has any level of dairy intolerance or cow's milk protein allergy. ByHeart's whole, intact cow's milk protein — while gently processed — will trigger the same immune response as any cow's milk formula in allergic babies
- If cost matters: ByHeart's per-ounce cost ($1.50) is actually lower than ProSobee's ($1.94). If your baby tolerates dairy, ByHeart is the better value per ounce while offering a meaningfully superior ingredient and nutrition profile