Childhood supplements: which ones do babies and children really need?
Of all childhood supplements, only vitamin D has strong evidence for most children: 400 IU (10 mcg) a day from birth for breastfed and partly breastfed babies in the US, while the UK also advises vitamin D for all children aged 1 to 4. Everything else in infancy and childhood is for a particular situation, such as a vegan diet or an early birth, or is usually not needed.
If the vitamin aisle leaves you wondering whether your child is missing out, that feeling is very common. In these years bones, teeth and blood are being built quickly, so a few nutrients earn extra attention, yet most of them arrive through milk and food. Below you'll find where a supplement has real backing, and where a plate of varied food is already doing the job.
Which childhood supplements does the evidence support?
The evidence supports a short list of childhood supplements. Vitamin D comes first, for breastfed and partly breastfed babies from birth, and for formula-fed babies until they drink about 32 oz (1 liter) a day (in the UK, until they take about 500 ml of formula a day). Vitamin B12 joins it for children on a vegan diet, from fortified foods or a supplement. A registered dietitian can look at the rest of a vegan child's diet with you and help fill any gaps.
Iron and fluoride are the two supplements a pediatrician or dentist decides on case by case. Babies born prematurely are often prescribed iron, and for other children iron-rich foods usually do the job. Fluoride reaches most children through toothpaste, and where tap water isn't fluoridated a pediatrician or dentist may prescribe it from 6 months.
It's also worth remembering that drops are only one part of how a child grows strong. Food, active play and exercise for children and rest all do their share, and our sleep page covers bedtime routines and sleep training for families who want them.
Graded by evidence
- strongVitamin D · 400 IU (10 mcg) a day from birth The one routine supplement for breastfed and partly breastfed babies; formula-fed babies may need none once they drink enough formula.
- Vitamins A, C and D drops · Daily drops, UK only Not routine in the US.
- Vitamin B12 · Amount set with a dietitian Essential if vegan.
- Iron · As prescribed Only if advised, with the amount set for the individual child.
- Fluoride · Via toothpaste; prescribed from 6 months where tap water isn't fluoridated A pediatrician or dentist decides, based on your local water.
- weakOmega-3 · No routine dose Oily fish is preferred over capsules or liquids.
- Multivitamins · No routine dose Usually not needed; may help very fussy eaters or children on restricted diets.
- Probiotics · No routine dose Mixed evidence; some evidence for specific strains in colic or diarrhea, and not needed routinely.
Does your child need a multivitamin, omega-3 or probiotics?
Usually not: a multivitamin is rarely needed by a child who eats a reasonable range of foods, though it can be a useful backstop for very fussy eaters or restricted diets. Many families find it easiest to keep every supplement, iron products especially, in a high cupboard with a child-resistant lid, so that gummies are never mistaken for sweets. If a child does swallow more than intended, it's worth calling poison control in the US, or the NHS in the UK, straight away rather than waiting to see how she is.
Omega-3 has weak evidence at this stage. Supplements haven't been shown to improve learning or behavior in most children, so oily fish on the plate is the preferred route. Probiotics sit in the middle: the evidence is mixed, with some support for specific strains in colic or diarrhea, and no case for giving them routinely to a healthy child.
Needs shift as girls grow, and supplements in puberty is for the years after this one. For the wider picture across life stages, see our guide to supplements for women.
How much vitamin D do children need in the US and the UK?
Vitamin D helps the body absorb calcium for strong bones, and milk alone doesn't always supply enough for a breastfed baby, which is why drops are advised from the first days. Our nutrient page on vitamin D explains what it does in the body. In the UK the amounts are 8.5 to 10 mcg a day for breastfed babies from birth and 10 mcg a day at ages 1 to 4, which lands close to the US figure.
The UK adds a second, separate line: daily vitamin A, C and D drops for all children from 6 months to 5 years. These are not routine in the US, where the AAP's advice centers on vitamin D alone.
Mothers who are pregnant or breastfeeding will find prenatal vitamins is the page written for them.
Facts
Common questions
Can a child have too much vitamin D?
It can happen when several products overlap, so it helps to add up everything your child takes. Drops, a multivitamin and fortified formula all count. Bring the labels to your pediatrician, or a pharmacist in the UK, when you start any new product, and ask them to check the total against the NHS safe upper limits.
Does your child need fluoride drops?
Only if your water is low in fluoride. Your water supplier can tell you the level, and a dentist can look at the first tooth when it appears and talk through varnish and toothpaste. Many families find it easiest to ask at the first dental visit, then again if you move or change water supply.
Who can help plan a vegan child's diet?
A registered dietitian can look at what your child actually eats, suggest fortified foods first, then supplements for any gaps that remain. Your pediatrician, or your GP or health visitor in the UK, can arrange a referral, and it often helps to bring a few days of food notes to the first appointment.
Should you give your child iron just in case?
Not as a precaution. The 2026 AAP iron report suggests checking breastfed babies at 9 to 12 months and formula-fed babies at 15 to 18 months, with children who have risk factors checked at annual well-child visits up to age 4. Those checks show whether your child needs iron, so a visit (or your health visitor or GP in the UK) is a good place to ask.
Do probiotics help with colic or diarrhea?
There is some evidence for specific strains in colic and in diarrhea, which means the strain on the label matters more than the word probiotic. It's worth asking your pediatrician or pharmacist which strain was studied for your child's problem, and how long to try it before deciding whether it's helping.
Can you get children's vitamin drops for free in the UK?
Some families can. Healthy Start is a UK scheme that provides free vitamin drops to those who qualify, and it isn't available in the US. A health visitor or midwife can tell you whether your family is eligible and where to collect drops locally; many families find it easiest to ask at a baby clinic.
Next steps
A good place to start is your child's next well-child visit, or a chat with your health visitor in the UK: ask whether vitamin D is covered, and mention B12 if your family is vegan or iron if your baby arrived early. Beyond that, a varied plate does most of the work, and you know your child's appetite, diet and routines better than any chart. What fits your family is yours to decide, because this is not one size fits all.
See a doctor promptly if you have
- a child crossing centile lines on the growth chart, or rapid weight loss or gain
- signs of puberty (breast development) before age 8, or a period before 10
Also in infancy & childhood
The same topic in the stage before and after
Sources
The guidelines and studies this page draws on.
- Vitamins for children, NHS (2025)
- Vitamin D, NHS (2025)
- Final Recommendation Statement: Prevention of Dental Caries in Children Younger Than Age 5 Years: Screening and Interventions, US Preventive Services Task Force (2021)
- Prevention, screening, diagnosis, and treatment of iron deficiency and iron deficiency anemia in infants, children, and adolescents (Powers et al., Pediatrics 2026), as summarized by Contemporary Pediatrics, Contemporary Pediatrics (2026)
- Dietary Guidelines for Americans, 2025–2030, US Departments of Agriculture and Health and Human Services (2025)