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Luleep Kids guide for parents

Which night light color is best for baby sleep?

Updated · Written by the Luleep team, based on the sources listed below.

For a baby's room at night, the best night light is dim and warm — amber, orange or red — and only as bright as you need to check on or feed your baby. The body clock is most sensitive to blue and bright white light, and studies show young children react strongly even to fairly low light in the evening. Brightness matters at least as much as colour.

Why light colour matters at night

In the evening the body releases melatonin, a hormone that helps time sleep. Light reaching the eyes can suppress it, and not all light is equal: a classic study found that the strongest effect comes from blue light, around 446–477 nm [1]. That is why the light from bright, cool-white lamps and screens is the least sleep-friendly kind of light at night.

Children appear to be more sensitive than adults. In one study, the same moderately bright evening light suppressed melatonin almost twice as much in primary-school children as in adults [2]. In preschool children, even an hour of quite dim evening light (5–40 lux) before bedtime suppressed melatonin markedly [3].

Warm vs cool light: what studies show

A small 2025 study compared two lights of the same brightness (20 lux) given to preschool children around bedtime: a warm 2,700 K light and a cool 5,000 K light. Melatonin suppression averaged about 24% with the warm light and about 56% with the cool light [4]. The study was small and preliminary, but it supports what light research in adults suggests: at the same brightness, warmer is gentler.

Two things to keep in mind:

  • Red is not “sleep light”. Red and amber light don't make the body produce melatonin; they simply interfere with it less. A bright red light is still bright.
  • Most research is in older children and adults. There is little direct research on night lights for babies, so these are sensible principles rather than precise rules. The NHS's practical advice is simply to keep the lights low at night [5].

How to choose and use a night light

  1. Pick a warm colour: amber, orange or red rather than blue, green or cool white.
  2. Make it dim. Just enough to see your way and check on your baby. If you can read comfortably by it, it is probably brighter than it needs to be.
  3. Place it low and out of the line of sight, not shining into the cot or your baby's eyes.
  4. Use it when you need it. For night feeds and nappy changes, a dim warm light is enough; many babies sleep fine in darkness the rest of the time.
  5. Keep daytime bright. Daylight in the morning and during the day helps the body clock learn the difference between day and night.

Using a phone as a night light?

Phone screens can be set very dim and warm, but they are not designed to be nursery lamps. Turn the brightness right down, let the screen fade out after a while, keep the phone well away from the cot and out of reach, and angle it so it doesn't shine into your baby's eyes. Turn off notifications that could light up the screen.

Questions and answers

What colour night light is best for a baby?

A warm colour such as amber, orange or red, kept dim. Blue and cool-white light have the strongest effect on the body clock, so they are best avoided at night.

Is a red night light better for sleep?

Red and amber light interfere less with melatonin than blue or white light at the same brightness. They don't make a baby sleepy on their own, and a bright red light is still bright, so keep it dim.

Should a baby sleep with a night light on?

It isn't necessary. Many babies sleep well in the dark; a dim, warm light is mainly useful for night feeds and checks. If you leave one on, keep it very dim and out of your baby's line of sight.

Sources

  1. Brainard GC et al. Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor. Journal of Neuroscience, 2001.
  2. Higuchi S et al. Influence of light at night on melatonin suppression in children. Journal of Clinical Endocrinology & Metabolism, 2014.
  3. Hartstein LE et al. High sensitivity of melatonin suppression response to evening light in preschool-aged children. Journal of Pineal Research, 2022.
  4. Hartstein LE et al. The circadian response to evening light spectra in early childhood: preliminary insights. Journal of Biological Rhythms, 2025.
  5. NHS. Helping your baby to sleep.
  6. Harvard Health Publishing. Blue light has a dark side.

This guide is general information for parents, not medical advice. Luleep Kids is not a baby monitor or a medical or safety device. If you are worried about your baby's sleep, breathing, hearing or health, talk to your doctor or health visitor.