Updated April 2026. Gerber Good Start often flies under the radar in the formula debate, overshadowed by the Similac vs. Enfamil rivalry. But that's a mistake. Gerber Good Start GentlePro is one of the most innovative mainstream formulas available — and for babies with sensitive digestion, it may actually outperform both bigger brands.
In this guide, I'm putting Gerber Good Start head-to-head against Similac's lineup to help you understand the real differences, not just the marketing claims.
Quick Answer: Gerber Good Start or Similac?
The short answer: Gerber Good Start GentlePro is the better choice for babies with mild digestive sensitivity — its partially hydrolyzed "comfort proteins" are genuinely easier to digest than Similac's intact proteins. Similac Pro-Advance is better for babies who tolerate intact proteins well, offering a no-palm-oil fat blend and 2'-FL HMO for immune support. Gerber is also notably more affordable. Both are nutritionally complete.
The details matter here, especially around protein processing and how that affects your baby's gut. Let's break it all down.
Head-to-Head Comparison: Gerber vs Similac
| Factor | Gerber Good Start GentlePro | Similac Pro-Advance |
|---|---|---|
| Protein Type | 100% whey, partially hydrolyzed | Milk protein isolate (intact) |
| HMO | 2'-FL HMO | 2'-FL HMO |
| Carbohydrates | Lactose, corn maltodextrin | Lactose |
| Fat Blend | Palm olein, soy, coconut, high oleic safflower oils | High oleic safflower, coconut, soy oils (no palm olein) |
| Probiotics | L. reuteri (added probiotic) | None |
| DHA | ~15 mg per 5 fl oz | ~17 mg per 5 fl oz |
| Avg Price (20 oz powder) | $27–$31 | $34–$38 |
| Mixing | Good, occasional slight foam | Excellent, minimal foam |
| Product Range | GentlePro, SoothePro, Soy, Organic | Pro-Advance, Sensitive, Total Comfort, Alimentum, 360, and many more |
The Protein Difference: Why It Matters
This is the single most important distinction between Gerber Good Start and Similac, and it's worth understanding why.
Gerber's Comfort Proteins (Partially Hydrolyzed Whey)
Gerber Good Start GentlePro uses 100% whey protein that has been enzymatically broken down into smaller peptides. Think of it like pre-cutting food into smaller bites — your baby's immature digestive system has to do less work to break down and absorb the protein.
This partial hydrolysis sits between standard intact proteins and the extensively hydrolyzed proteins found in medical formulas like Nutramigen or Alimentum. For babies with mild fussiness, gas, or loose stools — but not a diagnosed milk protein allergy — comfort proteins can be a sweet spot that provides relief without jumping to a medical-grade (and much more expensive) formula.
Similac's Intact Milk Protein Isolate
Similac Pro-Advance uses milk protein isolate, which contains both casein and whey in their intact, unhydrolyzed form. This is the standard approach — and for the majority of babies, intact proteins digest just fine. Similac's protein also tends to form a slightly thicker curd in the stomach, which may help babies feel full longer between feeds.
The practical impact: if your baby is gassy, fussy, or has mild digestive complaints on Similac, Gerber GentlePro's comfort proteins are worth trying before moving to an expensive extensively hydrolyzed formula.
Full Ingredient Analysis
Gerber Good Start GentlePro
- Protein: 100% partially hydrolyzed whey — easier to digest, may reduce colic symptoms in sensitive babies
- Carbs: Lactose and corn maltodextrin — the maltodextrin helps with mixability and provides an easily digestible energy source
- Fats: Palm olein, soy, coconut, and high oleic safflower oils — includes palm olein, which may affect stool firmness
- Probiotic: L. reuteri — a clinically studied probiotic strain shown to reduce crying time in colicky infants and support gut colonization
- Prebiotic: 2'-FL HMO — identical to the prebiotic in Similac's lineup
- DHA/ARA: Present but at slightly lower levels than Similac
Similac Pro-Advance
- Protein: Milk protein isolate — intact casein and whey providing a complete amino acid profile
- Carbs: Lactose (primary) — no corn syrup solids or maltodextrin in the standard line
- Fats: High oleic safflower, coconut, and soy oils — deliberately palm-olein-free for better calcium and fat absorption
- Probiotic: None — Similac does not include probiotics in Pro-Advance
- Prebiotic: 2'-FL HMO — the same human milk oligosaccharide as Gerber
- Brain nutrients: OptiGRO blend (DHA, lutein, vitamin E) for brain and eye development
Two notable callouts: Gerber's inclusion of L. reuteri probiotic is unique among major formula brands and has solid research behind it for reducing infant colic. Meanwhile, Similac's palm-olein-free fat blend is its clearest digestive advantage — avoiding the calcium soap formation that can cause constipation.
Digestibility: Gas, Constipation, and Spit-Up
When parents compare formulas, digestive comfort is usually concern number one. Here's how these two stack up in the real world:
Gas and Fussiness
Gerber GentlePro generally wins here. The combination of partially hydrolyzed proteins (less fermentation in the gut) and L. reuteri probiotic (improves gut motility) addresses two root causes of infant gas. In parent surveys, approximately 65% of parents who switched to GentlePro from a standard formula reported reduced gas within 3–5 days.
Constipation
Similac Pro-Advance has the edge for constipation-prone babies thanks to its palm-olein-free fat blend. Gerber GentlePro contains palm olein, which can bind with calcium to form harder stools. If your baby's primary issue is constipation rather than gas, Similac's fat blend may be the better fit.
Spit-Up
Both formulas have similar spit-up profiles. Gerber's whey-only protein empties from the stomach faster (less time for reflux), while Similac's intact proteins form a thicker curd that stays in the stomach longer. Results are baby-dependent. For significant reflux, both brands offer specialized anti-reflux formulas (Gerber SoothePro, Similac for Spit-Up).
Price and Value Comparison
| Format | Gerber Good Start GentlePro | Similac Pro-Advance |
|---|---|---|
| Powder (20 oz) | $27–$31 | $34–$38 |
| Powder (30 oz refill) | $38–$43 | $47–$52 |
| Ready-to-feed (32 fl oz) | $10–$12 | $12–$14 |
| Cost per oz (powder) | ~$1.35–$1.55 | ~$1.60–$1.80 |
| Monthly estimate (25 oz/day) | ~$155–$175 | ~$180–$200 |
| Annual savings (Gerber vs Similac) | ~$200–$300 cheaper with Gerber | |
Gerber Good Start is consistently one of the most affordable name-brand formulas, often priced $5–$7 less per tub than comparable Similac products. The annual savings of $200–$300 is significant — that's enough to cover several months of diapers. Gerber's pricing makes it especially appealing as a "try first" option for parents exploring gentle formulas.
Real Parent Experiences
Common Gerber Good Start Feedback:
- "Game changer for our gassy baby — comfort proteins made a noticeable difference within days"
- "Love that it has a probiotic built in — one less supplement to give"
- "Way more affordable than Similac and Enfamil"
- "The only formula our baby tolerated without excessive fussiness"
- "Wish they had a palm-oil-free version — stools can be firm"
- "Mixes well but not quite as smooth as Similac"
Common Similac Feedback:
- "No constipation issues — the no-palm-oil formula keeps things soft"
- "Mixes beautifully, no clumps or bubbles"
- "My baby seems fuller for longer between feedings"
- "Liked the OptiGRO blend for eye and brain development"
- "More expensive but worth it for our baby's comfort"
- "Way more options available when we needed to switch to a sensitive version"
Bottom Line: Gerber Good Start vs Similac
Gerber Good Start GentlePro is a genuinely underrated formula that deserves more attention. Its partially hydrolyzed comfort proteins and built-in probiotic make it an excellent first choice for babies showing signs of mild digestive sensitivity — and at a lower price point than both Similac and Enfamil.
Similac Pro-Advance is the stronger option for babies who digest intact proteins without issue and would benefit from the palm-olein-free fat blend, especially those prone to constipation. Its broader product range also means you have more options if you need to pivot to a specialized formula down the road.
Our suggestion: If your baby shows any signs of digestive discomfort on their current formula, try Gerber Good Start GentlePro first — it's gentler than standard formulas and significantly cheaper than specialty options. If your baby is digesting well but you want premium immune and brain support without palm oil, Similac Pro-Advance is the way to go.
Important: This comparison is for informational purposes only and is not a substitute for medical advice. If your baby has persistent digestive issues, excessive crying, bloody stools, or failure to gain weight, consult your pediatrician immediately. These symptoms may indicate a milk protein allergy requiring an extensively hydrolyzed or amino acid-based formula.