Formula & water.
Any iron-fortified formula. Distilled water, boiled, every bottle. Water in first. That’s most of it.
Every answer here is checked by an International Board Certified Lactation Consultant, the clinical credential for infant feeding. Where our IBCLC’s guidance differs from a published source, the answer says so.
Step 1: Choosing a formula
Iron-fortified. Then whatever fits your budget.
The brand matters less than you’d think. Iron is the part that counts.
The AAP recommends iron-fortified formula from birth to one year for every baby who isn’t breastfed, or is only partly breastfed. Once that box is ticked, it comes down to price and how well your baby’s tummy handles it.
Source: AAP (HealthyChildren.org)
Most babies start on cow’s-milk formula and stay on it.
Soy isn’t an automatic fix for a milk allergy: the AAP says up to 50% of babies allergic to cow’s milk protein also react to soy. Hydrolysed and amino-acid formulas are made for babies with a diagnosed allergy or condition. Fussiness on its own is common and usually has nothing to do with the formula. Thinking of switching? Ask your pediatrician first.
Step 2: Powder or ready-to-feed
Same nutrition. Different trade-offs.
- Powder What most families use. Cheapest over time. Not sterile: it can carry germs such as Cronobacter, which is why the water gets boiled.
- Liquid concentrate Mixed with an equal amount of water.
- Ready-to-feed No mixing. Commercially sterile, so the lowest risk of contamination or measuring mistakes. Also the most expensive.
Whichever you use, follow the water-to-formula ratio on that product’s label.
Sources: AAP (HealthyChildren.org); CDC; Nemours KidsHealth
Step 3: Water
Distilled. Boiled. Every bottle.
Use distilled water and boil it for every bottle, at every age.
Powdered formula isn’t sterile and can carry bacteria such as Cronobacter. Very hot water kills them. Skip tap water: it can carry contaminants like lead. Your formula label says how to boil the water and when to mix.
Yes. Boil it the same way.
It’s a better choice than tap water, which can carry lead. But it isn’t sterile.
Step 4: Making a bottle
Water first. Every time.
- Wash your handsAnd wipe down the surface you’ll prepare on.
- Boil distilled waterYour formula label says how long to boil it and when to mix.
- Water in, then powderMeasure the water first, then add exactly the scoops on the label.
- Cap it and shakeShake, don’t stir.
- Cool it, then testIt’ll be too hot to drink. Cool it under cold running water or in a bowl of cold water, then test a few drops on your wrist: warm, not hot.
- Never stretch it
- Too much water leaves your baby short of nutrients. Too little makes their kidneys work too hard.
- From the fridge?
- No need to warm it. If your baby prefers it warm, stand it in warm water. Never the microwave.
- Check the date
- Never use formula after its Use By date.
- Store tins cool and dry
- Indoors. Not in a car or garage.
Sources: CDC; Mayo Clinic; FDA Boiled distilled water: guidance from our IBCLC
Step 5: How long it keeps
Leftovers go. No exceptions.
| Formula | How long |
|---|---|
| Made, not yet fed | Within 2 hours. Not using it by then? Into the fridge right away, and use within 24 hours. |
| Once a feed starts | Within 1 hour. Then throw out what’s left. Mixed with saliva, it can grow bacteria. |
| Opened tub of powder | Most within 1 month. Room temperature, lid closed, not in the fridge. Check your label. |
Making night bottles ahead is fine, as long as they go straight into the fridge.
Source: CDC
Step 6: One more rule
Formula and water. Nothing else in the bottle.
No cereal, no sugar. The AAP warns cereal in a bottle can make a baby more likely to gag or breathe the thickened milk into their lungs, and that doesn’t change once solids start: cereal goes on a spoon. Thickened or anti-reflux formula is a separate case, used only under medical supervision.
The short version.
Formula & water in 6 lines.
Choosing a formula Any iron-fortified formula. The brand matters less than you’d think.
Powder or ready-to-feed Powder, liquid concentrate and ready-to-feed: same nutrition, different trade-offs.
Water Distilled water, boiled, for every bottle, at every age.
Making a bottle Water first, then exactly the scoops on the label. Never stretch it.
How long it keeps Once a feed starts, finish within 1 hour, then throw out what’s left.
One more rule Formula and water. Nothing else in the bottle.