Sleep deprivation is one of the most complex challenges of early motherhood. Many breastfeeding moms turn to melatonin to get a good night's sleep, but its effects on breastfed babies aren't fully known. While melatonin transfers into breast milk and may affect infant's circadian rhythms, its safety and long-term effects are not yet well understood for breastfed babies.

Understanding this connection is crucial for improving perinatal health. This article breaks down what we know about its safety, risks, and better alternatives for improving perinatal health.

Melatonin plays a key role in helping the body fall asleep and stay asleep. It works with the body’s natural clock, or circadian rhythm, to promote regular sleep patterns. To understand how melatonin may affect premature infants or babies born at full gestational age, knowing how the body makes it is essential.

Melatonin is made by the pineal gland, a small part of the brain that becomes active when it gets dark. This triggers melatonin production, helping the body feel sleepy. Melatonin levels usually rise in the evening and fall in the morning, supporting the sleep-wake cycle.

However, exposure to artificial light at night, such as from phones or TVs, can disrupt the pineal gland's melatonin production. This interference occurs because artificial light has a strong ability to suppress melatonin levels in humans.

In mothers, changes in melatonin levels may also affect the melatonin in breast milk, which plays a vital role in shaping a baby's sleep-wake cycle. Additionally, factors like poor diet and stress can inhibit melatonin synthesis, making these considerations particularly important for breastfeeding mothers.

Melatonin supplements are artificial forms of the hormone. Many people use them to manage sleep problems such as insomnia or jet lag. These supplements can help reset the body’s internal clock and improve nocturnal sleep in some cases, often referred to as melatonin treatment.

However, synthetic melatonin is not the same as the natural melatonin your body makes. Taking melatonin from outside the body, also called exogenous melatonin, may affect how much melatonin ends up in breast milk. Since melatonin levels in breast milk can influence a baby's sleep patterns, it is essential to understand the possible effects before using supplements while breastfeeding.

Melatonin does pass into breast milk. Studies show that melatonin levels in breast milk follow a daily pattern, with higher levels at night and lower levels during the day. This natural fluctuation may help regulate an infant’s sleep, especially for preterm birth babies, who have immature melatonin production. 

Melatonin has a short half-life in the body, and levels in breast milk tend to rise and fall in line with the mother's natural melatonin production. It has a short half-life, which means it breaks down quickly. Still, the timing of melatonin use can affect how much is present in breast milk during feeding. Taking melatonin supplements late at night may lead to slightly higher melatonin levels during nighttime feedings.

Several factors can influence melatonin levels in breast milk. These include the mother's light exposure, sleep habits, stress, and overall health. For example, exposure to bright lights at night can lower pineal melatonin synthesis. Breastfeeding moms with poor sleep or high stress may also have lower melatonin production, which could reduce melatonin in breast milk.

Breast milk melatonin follows the mother’s daily circadian melatonin cycle, with higher levels at night and lower during the day. This pattern may help infants begin to recognize the difference between day and night, especially in the early months when their own melatonin production hasn’t fully developed. 

Some studies suggest that breast milk melatonin could support infant sleep patterns and even reduce symptoms like fussiness during the night for breastfed babies. It has been associated with reducing infantile colic in some cases, though more research is needed.

Melatonin supplements are widely used to support sleep, but its safety during breastfeeding is still being studied. While some moms may consider melatonin use to manage sleep loss after childbirth, it’s important to weigh both the possible benefits and risks for themselves and their babies.

Some breastfeeding moms consider melatonin supplements to support sleep, but its effects during the postpartum period and on infants are not yet fully understood. Early research suggests a few potential benefits, though more studies are needed:

• May support maternal sleep by helping regulate rest during periods of postpartum insomnia.

• Could help maintain a regular sleep-wake cycle when used at night.

• Might aid infant circadian rhythm development through higher nighttime melatonin levels in breast milk.

• May offer benefits for preterm infants who do not produce their own melatonin in the early weeks.

• Could play a role in immune regulatory effects through melatonin’s presence in breast milk, although evidence is still limited.

More research is needed to confirm these effects and understand how melatonin use during breastfeeding may impact long-term infant health.

A healthcare provider may urge caution when using melatonin supplements while breastfeeding due to limited research and unclear safety guidelines. Some potential risks being studied include:

• Disruption of the infant’s developing melatonin rhythm if supplement use alters natural melatonin levels in breast milk.

• Confusion of the baby’s internal clock caused by irregular melatonin concentrations during daytime feedings.

• Unknown long-term effects on infant development, including how melatonin exposure may impact melatonin receptors or sleep patterns.

• Potential risks for preterm infants whose melatonin systems are still immature and may be more sensitive to hormonal changes.

• Limited data on perinatal health outcomes related to artificial maternal melatonin transfer through human milk.

Due to these concerns, it's important to consult a healthcare provider before using melatonin supplements while breastfeeding.

Breast milk contains biologically active melatonin that is absent in infant formula. Emerging research suggests these components play a critical role in infant gut-brain axis development and immune system regulation. The full implications for circadian rhythm development still require further study.

However, the presence of maternal melatonin transfer—contrasted with its absence in formula—may contribute to the observed developmental advantages of breastfeeding. This hormonal pathway represents an important but often overlooked difference between human milk and artificial substitutes. It may have potential implications for infant health outcomes across the lifespan.

Many breastfeeding moms want better sleep but may not feel comfortable using melatonin. Fortunately, there are safer options that support sleep without affecting breast milk. These include natural habits and gentle sleep aids that don’t interfere with melatonin levels in breast milk or disrupt melatonin stability throughout the day and night.

Improving sleep without supplements is possible through small, consistent lifestyle changes that support the body’s natural sleep-wake cycle. Some helpful strategies include:

• Keeping a regular bedtime to align with the body’s natural sleep-wake cycle.

• Lowering lights in the evening to encourage natural melatonin production.

• Limiting screen time at night to reduce light exposure that can suppress melatonin.

• Creating a quiet, dark sleep environment to support deeper rest.

• Eating foods rich in melatonin such as bananas, oats, or almonds.

• Spending time in natural sunlight during the day to strengthen the sleep-wake cycle.

• Reducing stress through calming activities like meditation or deep breathing.

These habits can help support a good night’s sleep without the need for supplements.

Some non-hormonal options are considered safer for breastfeeding moms. Herbal remedies like chamomile and lemon balm may promote relaxation without affecting melatonin levels in breast milk or interfering with the infant's sleep cycles or disrupting melatonin stability. Some believe chamomile tea may promote relaxation in mothers, though evidence of its effects on infant colic through breast milk is limited.

Magnesium is commonly used to support relaxation and may be part of a calming bedtime routine. For those seeking non-hormonal, high-quality supplements, these options offer a safer approach to improving nocturnal sleep. It can be taken through diet or supplements, but it’s best to check with a healthcare provider before use. These gentle aids avoid the risks linked to exogenous melatonin while still helping to improve nocturnal sleep and manage sleep disturbances.

If sleep problems continue for more than a few weeks, it may be time to talk to a healthcare provider. Constant poor sleep can affect both your health and your ability to breastfeed. Signs that you may need sleep support include extreme fatigue, trouble falling asleep even when the baby sleeps, and feeling anxious at night.

If you’re considering melatonin while breastfeeding, consult your healthcare provider. Ask about how it affects the breast milk, the baby’s sleep cycle, and overall perinatal health. Your healthcare provider can also help you explore safe alternatives or suggest treatments that support maternal sleep without risking the infant’s developing circadian rhythms know if you are considering melatonin use while breastfeeding.

Melatonin does pass into breast milk and may affect a baby’s sleep and circadian rhythm, but research on its safety for nursing mothers is still limited. Melatonin in breast milk follows a natural rhythm, with higher levels at night, which may help support the infant’s sleep-wake cycle. While melatonin may help with poor sleep, there are concerns about long-term exposure and changes in melatonin levels in breast milk. Before using melatonin supplements, talking to a healthcare provider is important. Safer options like improving sleep hygiene, boosting natural melatonin production, or using non-hormonal sleep aids such as chamomile or magnesium can support better sleep without added risks.