What’s the difference between Stage 1 to Stage 4 formula?
Confused about baby formula stages? Get insights on differences from Stage 1 to 4 to make informed feeding choices for your baby.
This guide breaks down exactly what's in each stage. We'll examine the science behind the stages, translate the confusing ingredient lists, and give you clear, practical advice.
Formula Stage Comparison
| Formula Stage | Age Range | Key Nutrients | Benefits | Kendamil Example |
|---|---|---|---|---|
| Stage 1 | 0–6 months | - Whey-to-casein ratio ~60:40 - Closely mimics early breast milk - Easy to digest |
Designed as a breast milk alternative for newborns; supports digestion and early growth | Stage 1 - Organic First Infant Milk 800g |
| Stage 2 | 6–12 months | - Increased iron content - Slightly higher protein - Supports introduction of solids |
Meets changing nutritional needs; replenishes iron stores and supports solid feeding | Stage 2 - Organic Follow On Milk 800g |
| Stage 3 | 12–36 months | - Higher protein levels - More casein for longer satiety - Supports growing appetite |
Bridges the gap between infant formula and toddler diet; supports sustained energy | Stage 3 - Toddler Milk 800g |
| Stage 4 | 36 months + | - Higher calcium and vitamin D - Balanced protein - Added iron and zinc |
Supports bone and muscle development during toddlerhood | — |
Stage 1 formula - nutritional composition
Stage 1 formula serves as the first alternative to breast milk for newborns from birth to 6 months. These formulas are carefully designed to mimic the nutritional profile of breast milk as closely as possible. The protein composition in Stage 1 formulas typically maintains a whey-to-casein ratio of approximately 60:40, which matches the protein balance found in human breast milk during early lactation. This ratio is significant because whey proteins are easier for newborns to digest than casein proteins.
Stage 2 formula - developmental benefits
Stage 2 formulas are developed for babies from 6 to 12 months of age, coinciding with the period when most infants begin consuming solid foods. The nutritional composition of Stage 2 formulas reflects the changing nutritional requirements of growing babies. The most notable change is an increase in iron content, as the iron stores babies are born with typically begin to deplete around 6 months of age.
Stage 3 formula - transition and adaptation
Stage 3 formula is specifically formulated for babies between 12-36 months, bridging the gap between infant formula and toddler milk. This stage corresponds with a period when babies are consuming more varied solid foods but still need significant nutrition from milk. The protein content in Stage 3 formulas is typically higher than in previous stages, with some formulas adjusting the whey-to-casein ratio to include more casein, which provides longer-lasting satiety for growing babies.
Stage 4 Formula – Nutritional Support for Toddlers Over 3 Years
Stage 4 formula is designed for children aged 36 months and older. Often marketed as "growing-up milk," this product category is essentially milk fortified with additional vitamins and minerals to support general health during early childhood.
Unlike earlier stage formulas, Stage 4 products typically do not contain prebiotics, HMOs, or specialised ingredients found in infant or follow-on formulas. Their primary role is to provide supplemental nutrients such as vitamin D, calcium, iron, and zinc, which may be beneficial for children with dietary gaps or picky eating habits.
It’s important to note that Stage 4 milk was developed as a marketing category to target parents of children over 3 years old, while avoiding regulations that restrict the promotion of infant formula for children under 36 months. As such, Stage 4 milk is not essential for every child, especially those with a balanced and varied diet, but may serve as a convenient option for added nutritional support when needed.
Signs your baby may be ready for the next stage
Physical and behavioral cues often indicate when a baby might benefit from transitioning to stage 2 formula onward. Increased hunger represents one of the most common signals. If your baby seems dissatisfied after regular feedings or wakes more frequently at night for feeds despite previously sleeping longer stretches, their nutritional needs might be changing.
Conclusion
Understanding the differences between formula stages is key to meeting your baby's changing needs. From Stage 1 that mirrors breast milk for newborns, to Stage 2 with added nutrients for six-month-olds, to Stages 3-4 supporting toddlers. Each formula is designed for specific developmental phases. The transition between stages should be guided by your baby's growth rate, health needs, and professional advice.
When deciding whether to switch stages or brands like Kendamil, always consult your pediatrician first. Your baby's growth metrics will provide clear indicators of readiness for the next stage. Remember to research thoroughly and compare nutritional profiles across brands.