Breast milk is a baby's most natural food — on its own for the first 6 months, and together with complementary foods until at least age 2. But every family's journey is different: a medical necessity, insufficient milk supply, or the mother's working conditions can bring infant formula into the picture. At this point the real issue is not the debate "is formula bad?", but being able to prepare the right formula, in the right measure, hygienically. A badly prepared bottle will tire the baby out no matter what the brand is.

In this article I explain how to choose formula, how to prepare it step by step, storage times, and the mistakes families make most often. Maintaining breastfeeding, increasing milk supply and signs of fullness are covered separately in our breastfeeding guide.

First, Let's Be Clear: Is Formula Really Necessary?

Some families start formula out of the worry that "my milk isn't enough"; yet most of the time the milk is sufficient and the problem lies in breastfeeding technique or frequency. The most reliable signs that milk supply is adequate are:

  • 6 or more wet nappies a day (pale yellow, odourless urine)
  • Regular, expected weight gain after the first few weeks
  • Audible swallowing sounds while feeding
  • The baby relaxing and settling after a feed

If these signs are present, do not rush into formula. Seeing your doctor for a growth-curve check and a breastfeeding assessment prevents unnecessary formula starts. And even if the decision is to start formula, you do not have to stop breastfeeding altogether; mixed feeding is possible for most babies.

What Do the Formula Stage Numbers Mean?

The numbers on the tins indicate differences in composition according to age group:

  • Stage 1 (0–6 months): First infant formula. Protein, mineral and energy content is adjusted to the newborn's kidney capacity.
  • Stage 2 (6–12 months): Follow-on formula. Used alongside complementary foods; iron and protein content is slightly higher.
  • Stage 3 and above (12+ months): Called growing-up milk; it is not essential for a healthy child with a balanced diet.

Phrases on the tins such as "prebiotic", "contains omega", "closest to breast milk" are marketing language; stage 1 formulas are legally subject to similar composition standards. For this reason there is no single answer to the question "which formula is the best?". For a healthy, term-born baby the right choice is a standard first infant formula suited to the age group; a higher price does not mean superiority.

Do not step outside the age group. Giving stage 2 formula to a baby under 6 months means an unnecessary mineral load; insisting on stage 1 in a baby older than 6 months may be insufficient in terms of iron. You can find a month-by-month plan for starting solids in our guide to complementary feeding.

Special Formulas: Who Uses Them, and Why?

Products you see on the shelf such as "AR", "HA", "lactose-free" and "hydrolysed" are formulas with a medical indication and should not be chosen on your own:

  • AR (anti-reflux): Contains a thickening agent. Not every baby who vomits has reflux; distinguishing them is the doctor's job.
  • HA (hypoallergenic): Contains partially hydrolysed protein. It is not an allergy treatment; it may be considered as a preventive measure in at-risk babies.
  • Lactose-free: Can be used for a limited period in temporary lactose intolerance following prolonged diarrhoea.
  • Extensively hydrolysed / amino acid-based: The actual treatment for cow's milk protein allergy. If there are findings such as blood in the stool, persistent eczema or poor weight gain, this diagnosis should be considered; I explained the details in our cow's milk allergy article.

For premature babies there are separate formulas with increased energy and protein density. Never start any special formula on a neighbour's recommendation.

Step by Step: How Is Infant Formula Prepared?

Powdered formulas are not sterile products; although rarely, bacteria may be present in them. That is why preparation technique matters at least as much as the choice of formula.

  1. Wash your hands and clean the worktop.
  2. Clean the bottles and teats. In the first 3–4 months and for premature babies, sterilisation by boiling is recommended; after that, thorough washing with hot soapy water and rinsing is enough for most babies.
  3. Boil the water and let it cool with the lid on for about 30 minutes (roughly 70 °C). This temperature inactivates any bacteria in the powdered formula.
  4. Put the water in the bottle first, then add the powder. If done the other way round the volume will be off and the feed will be too concentrated.
  5. Level off the scoop. Use the tin's own scoop; do not heap it or pack it down. The standard ratio is usually 1 level scoop per 30 mL of water; the instructions on the tin take precedence.
  6. Put the cap on and mix by rolling the bottle. Shaking hard creates extra air bubbles, which can increase gas complaints.
  7. Cool it quickly under running water and test it on the inside of your wrist: it should be lukewarm, not hot.
  8. Never heat it in the microwave. It heats unevenly; "hot spots" can burn the baby's mouth.

Swallowing too much air and a fast-flowing teat are common causes of gas complaints. I have gathered practical advice on colic and gas in our article on gas pains and colic in babies.

How Much Formula, How Many Feeds a Day?

Amount is what families struggle with most. Rather than giving a rigid table, I would like to remind you of two basic principles:

  • A rough guide: In the first 6 months the total daily amount of formula is roughly 150 mL per kilogram. For a 5 kg baby that means a total of 750 mL over 24 hours. This is not a target but a checkpoint.
  • The number of feeds decreases with age: While 8–12 feeds in 24 hours is normal for a newborn, as the months pass the number of feeds drops and the amount taken at each feed increases.

The most reliable guide, however, is the baby. Do not force the bottle to be finished. If the baby turns their head away, pushes the teat out, relaxes their hands and drifts off to sleep, they are full; struggling to make them finish the rest encourages vomiting and, later on, feeding resistance. Conversely, if the baby is still searching after finishing the bottle, is restless and has tightly clenched fists, you can increase the amount slightly at the next feed.

The right measure is not a single feed but weekly weight gain and the growth curve. Drinking less on one day is not a problem; the curve falling over a period of days is.

Storage Rules: Learn the Times by Heart

Situation Safe time
Freshly prepared formula Give immediately
Formula standing at room temperature Maximum 2 hours
In the fridge (4 °C, not fed from) Maximum 24 hours
Formula the baby has fed from, left over Discard within 1 hour
Warmed formula Never reheated or stored
Opened tin of powdered formula Usually 4 weeks (check the tin's instructions)

Additional notes:

  • Store the opened tin in a dry, cool place with the lid tightly closed; do not put it in the fridge (moisture causes clumping).
  • Do not put a wet spoon into the tin.
  • When going out, rather than preparing the formula and taking it with you, it is safer to carry boiled water in a flask and the powder in a separate container, and make it up on the spot.
  • In the summer months these times become even shorter; never compromise on formula that has been standing in the heat. I discussed the risk of fluid loss that hot weather creates in babies in our article on fluid loss in summer.

The 6 Most Common Mistakes

  1. Adding extra powder "to make it more nourishing" — Increases the renal load, causes dehydration and constipation.
  2. Diluting it to "make it last" — Leads to a calorie and protein deficit and poor weight gain; carries a risk of serious salt imbalance.
  3. Giving water alongside the formula (before 6 months) — A baby under 6 months does not need extra water and it can be harmful.
  4. Adding honey, sugar, molasses or cereal to the formula — Honey carries a risk of botulism before the age of 1; the others mean unnecessary calories and allergy risk.
  5. Leaving the bottle in the cot / feeding while the baby sleeps — Increases the risk of tooth decay and middle ear infection.
  6. Changing brands at every bout of fussiness — Switches made without giving the baby time to adapt do not solve the problem, they create confusion.

It is normal for stool patterns to change with feeding; the stools of formula-fed babies are usually darker and stronger-smelling. If the consistency becomes hard and straining begins, you can take a look at our article on constipation in babies.

When Should You See a Doctor?

In the following situations do not try changing the formula on your own — see a doctor:

  • Blood or mucus in the stool
  • Forceful, projectile vomiting or vomiting that recurs after every feed
  • The baby failing to gain weight or losing weight (especially not regaining birth weight by the 2nd week)
  • Turning blue, choking, wheezing during feeds or marked difficulty breathing
  • Allergic signs such as a widespread rash or swelling of the lips and eyelids (sudden swelling with breathing difficulty is an emergency)
  • Persistent diarrhoea, fewer than 6 wet nappies a day, a dry mouth, crying without tears and other signs of dehydration
  • Ongoing refusal to feed, being too lethargic to wake
  • A fever of 38 °C or above in a baby under 3 months

Apart from these, your regular well-child check-ups are the best setting for decisions about formula choice, amounts and the feeding schedule. During well-child follow-up, where the growth curve is monitored, the feeding plan is personalised for your baby.

In Summary

Infant formula is a safe method of feeding when the right stage is chosen, the tin's measurements are followed exactly and hygiene rules are observed. Three key sentences: do not play with the measurements, prepare it fresh, stick to the times. Special formulas, meanwhile, are chosen through examination — not through advertising.

To assess your baby's feeding, weight gain and formula choice together in Gaziantep, you can book an appointment. You can find detailed information about my clinic and working hours on my Gaziantep paediatrician page.