NalaIs red light better than white light at night for a baby?
Probably, as long as it is dim. Studies in adults and young children show that blue and white light hold back melatonin, the hormone that helps us feel sleepy, much more than red or amber light. A dim red light is likely the gentlest way to see during a night feed, though no study has tested this in babies under one.
If you want to use your iPhone as that light, here is how to set up a red night light for night feeds.
What light does to the body clock
Light is the main signal our body clock uses to tell day from night. Special cells in the eye pick it up and, in the evening and at night, light tells the brain to hold back melatonin. That is useful in the morning and unhelpful at 3am.
Those cells don't react to all colors equally. Two classic studies in adults, in 2001, found that blue light, around 446 to 480 nm, was the most powerful at suppressing melatonin at night (1, 2). A third study compared colors side by side at the same energy: blue and green light suppressed melatonin the most, and the longer red and amber wavelengths less (3). Less, not none. Brightness and how long the light is on matter too.
White light from a ceiling lamp or a phone flashlight contains a lot of blue. That's why it feels so jarring in the middle of the night.
Are children more sensitive?
It looks that way. In a small study of 3 to 5 year olds, one hour of bright evening light cut their melatonin by almost 90%, and it stayed low for close to an hour afterwards (4). A follow-up study found that even fairly dim light, 5 to 40 lux, suppressed melatonin by around three quarters in 3 and 4 year olds (5). School-age children have shown about twice the suppression of adults under the same light (6).
Color seems to matter for children too. In a 2025 pilot study, warm 2700 K light suppressed young children's melatonin far less than cool 5000 K light of the same brightness, about 24% against 56% (7).
What about babies?
Here I have to be honest: I found no study that measured how light color affects melatonin in babies under one year old. Nobody can tell you that a red light will keep a newborn asleep, and I won't.
What we do know is that babies learn day and night from light. In one study, babies aged 6 to 12 weeks who slept better at night had been exposed to more daylight in the early afternoon (8). And the advice from health services is consistent: keep nights dark and calm. The NHS suggests keeping the lights down low and your voice quiet at night (9). The American Academy of Pediatrics suggests not stimulating babies when you feed or change them at night (10). Australia's Raising Children Network says a dim night light can help with night feeds without stimulating your child (11).
Put together: bright days, dark nights, and when you need light at night, the dimmest and warmest you can work with. Red is the color your body clock is least sensitive to.
How strong is the evidence?
| Who was studied | What was found | How strong |
|---|---|---|
| Adults | Blue light suppresses melatonin the most at night; red and amber suppress it less, not zero (1, 2, 3) | Several controlled lab studies, repeated over 20 years |
| Preschool and school-age children | Evening light suppresses melatonin more than in adults, even when fairly dim; warm light less than cool light (4, 5, 6, 7) | Small studies; the color comparison is a 2025 pilot |
| Babies under one | Daylight in the afternoon was linked to better night sleep at 6 to 12 weeks (8). Light color and melatonin: not studied | Research gap. Advice relies on health services' guidance to keep nights dark and calm (9, 10) |
So the adult and child findings point in the same direction, but they don't prove that a red light changes how a newborn sleeps.
Night light checklist
- Color: red first, then amber or warm white. Avoid cool white and blue.
- Brightness: just enough to see your hands. Lower than you think.
- Direction: light pointing away from the baby's face, toward your hands or the wall.
- Duration: on for the feed or the change, off when the baby is back in bed.
- Daytime: open the curtains in the morning and get outside in the afternoon when you can.
- Safety: nothing in the crib, cords at least 3 feet (1 meter) away from it (12).
How Nala helps
I built Nala for my son's night feeds. It turns your iPhone into a deep red light, using the deepest red the screen can show, dimmable down to 5%. Tap the light and every button disappears, so the screen shows only red. A timer can switch it off when you've gone back to sleep. The red light is free. How to set it up for night feeds.
Questions parents ask
Is red light better than white light at night for a baby?
Probably, as long as it is dim. Studies in adults and preschool children show that blue and white light suppress melatonin much more than red or amber light. No study has tested this in babies under one, but dim, warm or red light during night feeds follows the advice of the NHS and the AAP to keep nights dark and calm.
Does red light have no effect at all on sleep?
No. Red light has less effect than blue or white light, not zero. Brightness matters too, which is why the light should be as dim as you can manage and only on while you need it.
Should a baby sleep with a night light on all night?
Most babies don't need one. A dark room at night and plenty of daylight during the day help them learn the difference between day and night. A dim light is useful for you during feeds and changes, then it can go off.
What about amber or warm white light?
Warm light is a reasonable middle ground. In a small 2025 study, warm 2700 K light suppressed young children's melatonin less than cool 5000 K light of the same brightness. Red is the furthest from blue, amber and warm white come next.
Next, read
- Set up your iPhone as a red night light for night feeds
- How to do night feeds without fully waking up
- Night lights for an older child scared of the dark
Sources
- Brainard GC et al. Action spectrum for melatonin regulation in humans. Journal of Neuroscience, 2001.
- Thapan K, Arendt J, Skene DJ. An action spectrum for melatonin suppression. Journal of Physiology, 2001.
- Wright HR, Lack LC. Effect of light wavelength on suppression and phase delay of the melatonin rhythm. Chronobiology International, 2001.
- Akacem LD, Wright KP, LeBourgeois MK. Sensitivity of the circadian system to evening bright light in preschool-age children. Physiological Reports, 2018.
- Hartstein LE et al. High sensitivity of melatonin suppression response to evening light in preschool-aged children. Journal of Pineal Research, 2022.
- Higuchi S et al. Influence of light at night on melatonin suppression in children. Journal of Clinical Endocrinology & Metabolism, 2014.
- Hartstein LE et al. The circadian response to evening light spectra in early childhood: preliminary insights. Journal of Biological Rhythms, 2025.
- Harrison Y. The relationship between daytime exposure to light and night-time sleep in 6-12-week-old infants. Journal of Sleep Research, 2004.
- NHS. Helping your baby to sleep.
- American Academy of Pediatrics, HealthyChildren.org. Getting your baby to sleep.
- Raising Children Network. Light, noise and baby sleep: FAQs.
- U.S. Consumer Product Safety Commission. Baby monitor cord safety alert.