Red Light Therapy and Sleep

You’ve probably seen it all over wellness blogs and Instagram, people basking in a soft red glow like tomatoes with a subscription to Goop. But beyond the trend is there actually something here to help your sleep? Short answer, maybe. So lets have a dig into what is out there in terms of research and opinion..

What is Red Light Therapy?

Red light therapy uses specific wavelengths of red and near-infrared light (typically between 600–1000nm) that penetrate your skin and, according to researchers, stimulate your mitochondria (is it even a blog about a wellness trend if we don’t mention mitochondria?). That’s science-speak for “helping your cells do their jobs better,” including repairing tissue, reducing inflammation, and potentially balancing hormones.

And for sleep? Well I think we are all more aware of blue light, which has always been thought to mimic the sun, and that any exposure to it close to bedtime disrupts the body’s circadian rhythm and reduces melatonin production - an important hormone for sleep timing. However, that view is being challenged by the likes of Michael Gradisar claiming that based on his research blue light doesn't have the impact on sleep that we thought it did  - then on the other side of the discussion you have Martin Moore-Ede, who claims blue light is toxic and that any device containing it should have a government warning sticker as it is so bad for your health. My view is closer to Michael’s than Martin's  - but what they both agree on is that red light therapy could be useful before bed, as it mimics the glow we once had from fire, or candles, or even the old fashioned light bulbs.

The logic is solid, it may actually signal to your brain that it’s time to chill out and get sleepy - sort of like a digital sunset for your pineal gland.

The case that Red Light Therapy helps your sleep

A 2012 study on female basketball players (a small sample of 20 players, so not great) found that 30 minutes of red light therapy nightly for two weeks led to significantly improved sleep quality and melatonin levels compared to the control group. Other small studies have shown improvements in people with insomnia, particularly when red light is used consistently before bed. Additionally there is some proof that it could be beneficial for people with Alzheimer’s when it comes to sleep, but this would need more investigation.

The case against Red Light Therapy

We really need to be cautious before over emphasising the brilliance of Red Light Therapy when it comes to answering sleep issues. The research is still limited. A lot of the studies are small, short-term, or not very diverse in participants. Plus, there’s a big difference between clinical-grade red light therapy (the stuff used in studies) and what you buy off Amazon or the influencer putting red light bulbs in her fridge and claiming it will help you sleep better….

Also, not everyone reacts the same. Some folks swear by red light for deeper sleep and smoother wakeups, while others feel no real difference or even end up feeling more active and alert, which was shown in some of the research. There’s also very little long-term data on how daily exposure might affect people with conditions such as bipolar disorder, migraines, or hormone sensitivity. 

It is one of those sleep answers that just needs more research - and the fear is this won’t happen and so it becomes the sort of product category that focuses its spending on influencer marketing rather than clinical research. There currently isn’t an agreed process - what some might call a protocol - for optimal use in terms of timing, and there’s no agreed standard for the best frequency of light. If this is not addressed it will start to be viewed as faddy snake oil, where potentially it could be incredibly helpful.

A bit more depth on the research

A study from Zhao et al¹ involving elite female basketball players found that 14 days of 30-minute nightly red light exposure improved sleep quality and increased serum melatonin levels compared to the control group, but this was a very small sample. 

Research from Pan et al² on effects on sleep and mood in individuals with insomnia indicates that red light can increase subjective alertness and improve drowsiness in participants with insomnia. However, it may also elevate anxiety and negative emotions, potentially affecting sleep quality. ​

A study on mitigation of sleep inertia from Figuiero et al³ demonstrated that saturated red light delivered through closed eyelids at levels not suppressing melatonin can reduce sleep inertia upon waking, enhancing alertness. ​

There could be a potential benefit for Alzheimer’s patients as shown in this meta-analysis of 15 randomised controlled trials from the Alzheimer’s Association⁴  that suggests that red light therapy may alleviate sleep disturbances and psychobehavioral issues in Alzheimer's disease patients, improving overall quality of life.

So, should we use it?

If you’re dealing with chronic sleep issues then there are many things I would recommend first - and for all of us struggling to sleep, you need to work out what your issue is. Red Light Therapy is not going to help a bad back, but a new mattress might do. If you struggle to wind down before bed, it could be a really powerful thing to add to your pre-sleep ritual, and even if the science never quite gets there, it will do no harm and placebos can be very powerful in helping us sleep better.

If you are going to try it, look for devices that list wavelength specs (ideally around 630–850nm), start slow (around 10–20 minutes in the evening), and give it a couple of weeks to see if your sleep improves.

Bottom line? Red light therapy might not be the magic bullet, but it’s more than a fancy flashlight.

References:

1. Zhao, J. et al. (2012) Red Light and the Sleep Quality and Endurance Performance of Chinese Female Basketball Players, National Library of Medicine. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC3499892/.
2. Pan, R. et al. (2023) Effects of red light on sleep and mood in healthy subjects and individuals with insomnia disorder, National Library of Medicine. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10484593/.
3. Figueiro, M.G. et al. (2019) Effects of red light on sleep inertia, National Library of Medicine. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6506010/.
4. Gordon, S. (2023) Study: Light Therapy May Help Ease Symptoms of Alzheimer’s Disease Like Sleep, Mood, Health.com. Edited by N. Blackmer. Available at: https://www.health.com/light-therapy-alzheimers-disease-symptoms-8413154.