Vitamin D drops, probiotics and baby sleep: is there a link?

About the scope of this page: Dr. Sam holds a Doctor of Pharmacy and is a licensed pharmacist, not a physician. What follows is a general explanation of how a medicine, supplement or remedy connects to sleep, and it is no substitute for your child’s pediatrician. Before giving your child any medicine, supplement or remedy, talk to your child’s pediatrician and follow the product label.

The quick answer

For many babies, vitamin D drops are a standard part of infant care, and you should carry on giving them as your pediatrician recommended. They do not treat sleep, and a bigger dose will not make sleep better. Probiotics are another matter: optional products that vary widely, with mixed evidence for colic and no demonstrated effect on sleep.

If a question about supplements is really a question about sleep, Actually Sleeping can help. Dr. Sam, a pharmacist, leads the practice, so supplement questions get serious attention and medical ones are directed to your pediatrician, while the plan focuses on how your baby sleeps.

Vitamin D: what research shows

• Why it is given. The AAP advises a vitamin D supplement for every infant, except babies taking in enough vitamin D-fortified formula. Breastfed babies in particular need it. Your pediatrician will tell you which product to use and how much.
• Sleep. In the VIDI randomized trial, infants who received a higher daily vitamin D dose gained no sleep benefit up to age 2 compared with those on the standard dose. The researchers did observe an association between higher vitamin D blood levels and better sleep, but an association does not prove that vitamin D causes better sleep.
• More does not mean better. The AAP points out that fat-soluble vitamins build up in the body and could make a child ill at very high levels. Use the measuring device supplied with the product, and never give a double dose.

Probiotics: what research shows

• Colic studies disagree. Trials of a single probiotic strain reported benefits in breastfed babies with colic, but a later trial that also included formula-fed babies found none. Even where crying decreased, that is not the same thing as longer sleep.
• Regulation. According to the FDA, it has not approved any probiotic product for use as a drug or biological product in infants of any age. Probiotics are usually sold as foods or dietary supplements.
• Babies born preterm. In 2023 the FDA warned that probiotic products given to preterm infants in hospital had contributed to serious infections, including the death of one infant. If your baby arrived early, do not begin a probiotic without your pediatrician.

Why parents think they see a difference

Babies change quickly. A new supplement often begins during the same weeks as a growth spurt, a nap shift or the natural easing of colic at around 3 to 4 months. It is easy to give the drops credit for a change that simply came with time.

Questions for the pediatrician

• “Does my baby need vitamin D drops, given how they are fed?”
• “Is a probiotic reasonable for my baby’s crying, and which one, if any?”
• “My baby was born early. Is any supplement unsafe for them?”

A sleep problem is not solved with medicine

Continue giving vitamin D as your pediatrician recommended. For sleep, look elsewhere: at the schedule, the routine and the way your baby falls asleep. Each of those differs from baby to baby, which is why age charts like wake windows by age are only a place to begin.

Actually Sleeping shapes all of that into a plan for your baby: age, feeds, temperament, the way they currently fall asleep and your family’s day. You receive bootcamp-style coaching before the first night, 1:1 check-ins every day and nap coaching until naps are solid. Your custom plan decides how night feeds are handled, based on your baby’s age. Parents talk about the difference in the client video reviews.

Book the free consultation to go over your baby’s sleep.