Red light phototherapy (3/3): Hair regrowth, Pain reduction, Wound healing and Practical applications

Last Updated on June 8, 2019 by Afifah Hamilton
Read Time: 10 min

This is the third and final post looking at the huge body of research that is uncovering the remarkable health benefits of red light. In this post we look at eh evidence for red-light phototherapy to increases hair regrowth, relieve pain, heal wounds, and conducer practical ways to make use of these ideas.

Red Light Series:

Part 1: Skin (click to read)
• Red light and skin rejuvenation, collagen production and wrinkle reduction
• Red light protects skin from photo-ageing

Part 2: Brain, Muscles and Eyes (click to read)
• Red light and brain health
• Red light enhances muscle performance and exercise recovery
• Red and infra-red light protect the retina

Part 3: Hair regrowth, Pain, Wound Healing and Practical Ideas (this post)
• Red light increases hair regrowth
• Red-light for pain relief
• Red-light for wound healing
• Practical ways to make use of these ideas


In researching these three posts I have been constantly surprised that red light exposure demonstrates measurable effects at very low doses and durations: it seems just a few minutes per day with standard LED lamps are enough to produce measurable hair regrowth, exercise enhancement or speed up wound healing. The greatest length of exposure in the papers I looked at was for brain stimulation where the duration required 30 to 60 minutes per day for approximately ten days. But in such cases, a single LED placed in one nostril appears to be sufficient!

And all of these benefits were produced without any recorded side effect in any of the papers I looked at. The only danger appeared to be if the light source was so powerful as to produce heating effects (as concentrated laser beams might), but with standard LEDs, even super bright ones, no damaging heating effect was observed. Red light really is the gift that keeps on giving!

Why are red light panels not built into shower units? LEDs behind a glass or perspex screen would enable everyone to have a five-minute red-light ‘bath’ as part of their daily routine – there has to be a market there for some enterprising type. It really seems like a no-brainer. While we wait for that invention to come along, there are ways we can incorporate red light sources into our lives, and I will outline these towards the end of this article.

Red light increases hair regrowth

One of the first experiments with red laser light in the 1960’s attempted to induce skin cancer on a shaved patch of mouse skin. To the surprise of the researchers instead of leading to cancer (red light does NOT induce cancer), it caused the fur to re-grow faster in the treated mice than the untreated controls. [ref]

Similarly, unexpected results have been reported for laser hair removal, where 1 in 20 patients in some studies experience new hair growth around the site of the treatment. [ref]

Many studies have now looked at the use of red lasers or LEDs for improving hair growth or slowing hair loss. These include male and female hair loss, patent baldness, alopecia and chemotherapy recovery. Results are mostly positive, with increased growth (or re-growth) rates, number of follicles and hair thickness all reported. In these studies LED or laser combs were used, typically for just 20 minutes per week. [ref]

In the ‘real world’, however, people using commercial devices report mixed results, with a sizeable minority (~30% from a quick check of Amazon reviews) saying “It didn’t work for me”, whilst some report “Amazing results”. Interesting features of some of the trials were (1) that even when objective improvements in hair growth rates, hair thickness and follicle numbers were clearly established when people were shown photographic comparisons between treated patients and controls they could not tell the difference. (2) in trials that demonstrated increased hair re-growth (for example, following chemotherapy) after one year no difference was subjectively observable. [ref

Red-light for pain relief

The modern use of red light for pain reduction was initiated by NASA [see their web page] who trialled a red LED panel – originally developed to grow plants in space – for pain relief in chemotherapy. A whopping 96% of patients had significant pain relief, and NASA showed that the effect was due to the visible red light, not due to heating or infra-red wavelengths.

Red Light Pt3 Pain and Muscles

Since then red light has been shown to assist pain reduction in a raft of conditions. A 2015 review summarised the studies thus far:

Acute orthopedic conditions such as sprains, strains, post-surgical pain, a whiplash injury, muscular back pain, cervical or lumbar radiculopathy, tendinitis and
chronic conditions such as osteoarthritis, rheumatoid arthritis, frozen shoulder , neck and back pain, epicondylitis, carpal tunnel syndrome, tendinopathy, fibromyalgia, plantar fasciitis, post tibial fracture surgery and chronic regional pain syndrome are amenable to red light therapy. Dental conditions producing pain such as orthodontic procedures, dentine hypersensitivity, and third molar surgery respond well to treatment with (red light). Neuropathic pain conditions can also be treated such as post herpetic neuralgia, trigeminal neuralgia, and diabetic neuropathy. Due to the wide spectrum of conditions one would surmise that multiple mechanisms can operate to achieve pain relief.

– Cotler et al, The Use of Low Level Laser Therapy (LLLT) For Musculoskeletal Pain, MOJ Orthop Rheumatol (2015)

Such treatment has been shown to have short, medium and long-term benefits through a raft of mechanisms. From the same paper:

  • Fast acting pain relief occurs within minutes of application, which is a result of a neural blockade of the peripheral and sympathetic nerves and the release of neuro-muscular contractions leading to a reduction of muscle spasms.
  • In the medium term, there is a decrease in local oedema and a reduction of inflammation within hours to days. The action of (red-light) in reducing swelling and inflammation has been well established in animal models as well as in clinical trials. The numbers of inflammatory cells have been shown to be reduced in joints in collagen-induced rheumatoid arthritis, and in acute pulmonary inflammation. The expression levels of pro-inflammatory cytokines have been shown to be reduced by red light in burn wounds, in muscle cryo-lesions and in delayed-type hypersensitivity.
  • The long-term effects of (red-light) occur within a week or two and can last for months and sometimes years as a result of improved tissue healing.

Although NASA used red LEDs, many of the studies above used far-red or near infra-red light, with longer wavelengths that penetrate more deeply.

Considering the simple, non-invasive nature of using red light to treat such a broad basis of pain it is surprising that the procedure is not more common. I guess that in a hospital setting the effort of wheeling around a red lamp from patient to patient simply can’t compete with the convenience of dishing out pharmaceutical painkillers.

Red light in wound healing

Red light [ref], green light [ref] and blue light [ref] have each been shown to increase wound healing, but through different mechanisms, although the majority of research has been on red light. Taken together, these suggest that full spectrum sunlight would be highly effective at enhancing wound healing, yet our modern indoor lifestyle coupled with the standard treatment of covering wounds to prevent infections suggests we are missing a trick.

Many Victorian and early 20th-century hospital wards were designed to let light stream in through open windows, and beds were wheeled into the open sunshine, or even outside (see image below). They saw the sunlight and fresh air as uniquely beneficial, and it seems they were right. New Scientist covered the science behind this a few year’s back in an article titled ‘Fresh air and sunshine: The forgotten antibiotics‘.

During the first world war, Oskar Bernhard gained a reputation for using sunlight to recover severely injured limbs that would normally have been amputated by other surgeons. He never lost a patient to tetanus or gangrene.  His success with sunlight brought national and international recognition. (Richard Hobday, The Healing Sun, Findhorn Press, 1999)

Multiple mechanisms seem to be at play in red light wound healing including increased fibroblast growth factor expression and enhanced macrophage activation during the initial stages of wound healing [ref]. Green light uniquely increases leptin and interleukin 8 (leading to increased cytokine signalling) and vascular endothelial growth factor (which stimulates blood vessel growth) [ref]. Blue light is recognised as anti-microbial, so may help in wound healing through such a mechanism. It also stimulates the release of nitric-oxide [ref]. All three wavelengths (and hence full spectrum light) promote angiogenesis (blood vessel growth) which helps to reduce tissue necrosis, especially important in complicated wounds [ref].

Practical Suggestions

How can we put the fascinating ideas explored in this series of posts into practice?
The following are some ideas I have tried myself, and are quite easy to arrange. How effective they will be for a given condition is beyond the scope of this post so you will need to experiment with duration and frequency of treatment and let me know how you get on. Although red light is very safe in the form of low power LEDs light bulbs, do not use laser pens, especially directed into the eye, as they produce a very intense point of light.

GU10 red LED bulbs.

GU10 LEDs are relatively cheap and long lasting

There are several of these available online. They vary in power from 1W to 6W.

Make sure you buy GU10 LEDs and  NOT red GU10 tungsten halogens as halogens get much too hot to bring close to the skin and will certainly burn if they touch it. You get more red light, more cheaply and safely with LEDs.

Generally speaking, the higher the power the shorter the duration of exposure needed to gain benefit. Take care, however, as at the higher powers even LED bulbs will get noticeably warm in use and might burn if they touch the skin. At the lower power end of the range, the bulbs can be placed much closer, even touching the skin as they remain cool for even prolonged periods.

Anglepoise lamp.

anglepoise GU10
Anglepoise lamps can allow you to shine red light on the affected area while you relax in your favourite chair

With a bit of searching online, you can find angle-poise lamps that will take GU10 bulbs.

A GU10 red LED can be purchased separately and placed in the anglepoise to make a good red-light source for focusing on part of the body while you relax of an evening. For skin collagen, wrinkles, hair loss, minor wounds etc simply direct it at the appropriate part of the body. If directed straight at the face you do not necessarily need to wear goggles, just keep the eyes closed. The red light that gets through the eyelids is beneficial for the retina.

Collagen LightBox.

collagen light box
Collagen light boxes are expensive, but effective for daily use on the face or legs.

This is a more expensive manufactured unit which I have in my clinic but could be a worthwhile investment if you intend to use it regularly. It has fold out panels that sits on the table and can be angled to expose all parts of the face, or placed on the floor to do the legs.

It has a timer and instructions for use. It contains twelve red fluorescent tubes which will eventually need replacing but should last for many years. Although marketed for collagen production and wrinkle reduction, it is suitable for all of the other benefits identified in these posts. You can feel the warmth of the tubes after a couple of minutes, so you are getting infra-red too which is beneficial for deeper muscles and blood vessels.

Red light Nasal Units

Nasal red-light units are available online and come with some positive reviews.

As we saw in post 2, red light via the nasal passages may have benefits for the brain and a range of neurodegenerative conditions. To my knowledge, no units have been commercialised for this purpose, but there are nasal units sold to treat rhinitis (hayfever), which should do the job.

You can find them on Google from £15 to £50. Most are battery powered. Some are portable and wire-free.
I have not tried them, so cannot comment on their efficacy, but they are relatively cheap, and if you don’t mind looking like Rudolf, they are easy to use whilst relaxing in the evening.

They seem to have very positive reviews on Amazon where many hayfever sufferers giving them five stars. If you want to try them for improving brain health you may need to use them for longer periods than recommended for hay fever (e.g. half an hour at a time).

Red light at night… Your sleep will be right.

As covered in our previous post on sleep health, red light in the evening helps regularise the circadian clock and can improve sleep quality. Indeed recent studies suggest that exposure to red light shifts the heart-beat to breathing ratio closer to 4:1 – a pattern associated with relaxation and health:

Such a coordination has been observed in healthy subjects during quiet rest as well as during nighttime sleep. The emergence of this coordination indicates a process of relaxation and recovery of the organism.

 Impact of Colored Light on Cardiorespiratory
 Friedrich Edelhäuser et al, 2013

A good way to achieve better evening lighting conditions is to reduce lighting levels generally. Dimming tungsten halogen lamps moves their colour towards the red end of the spectrum, however, most dimmable LED lamps won’t do this as they get dimmer but not redder, fortunately, there are some now that redden as they dim.
When selecting bulbs to enhance red-light in the evening you need to check their colour temperature.

When purchasing lamps look for the colour-temperature information. For general lighting warm white (2700 kelvin) gives the traditional tungsten filament glow as it has enhanced red light content. Extra-warm (2000 – 2500K), however, will provide the most red light.
A very warm LED bulb
Tungsten lamps produce an abundance of red-wavelengths

The outdoor colour temperature at sunrise or sunset is close to 2000K at which time it contains the highest ratio of red light and relatively low levels of blue light. It passes through 3500K early in the morning or late afternoon and has a peak colour temperature around midday of 5500K to 7500K when blue light (and UV) reaches a peak.

Along with dimming lights in the evening, another way of increase red light exposure is to replace the bulbs in one or two table lamps with red or amber tint bulbs. The old ‘fire glow’ bulbs will do, as will very-warm white LEDs (2500K or lower). Of course, the ultimate red-light source is an open fire! The flickering flames seem to have an additional calming and hypnotic effect.

Avoiding the Evening Blues

Whilst increasing your red light exposure of an evening will help your brain get ready for sleep, sources of blue light work the opposite way, signalling daytime to a confused body clock. Blue light strongly suppresses melatonin production [ref]. Melatonin is a key circadian rhythm regulator, and its production naturally peaks 2 hours after dark [ref]. Consequently, blue light in the evening can be enough to shift the body clock by 3 hours. This light-based circadian rhythm operates through cells in the retina and is active even in some otherwise blind individuals.

Blue light sources should, therefore, be minimised, especially prolonged close-up screen viewing late in the evening.

To this end, Apple has recently introduced a feature to its phones and computers called night shift which makes the screens of its devices become redder (less blue) in the evenings. For other computer systems, you can download similar apps such as flux, which is the one I use on the computer I am writing on now. Several monitor manufacturers are including blue filters to reduce blue light from their screens.

Credit: Simon Wakefield

I hope you have enjoyed this series of posts – if so click on the like button below or share on social media. Over one hundred hours of research have gone into preparing them, and there is a good deal left to say on the topic of light and health. In a future post, I hope to look at the different artificial light technologies, comparing tungsten, fluorescent and LED each of which produces a different spectral pattern despite appearing similar to our eyes.

3 thoughts on “Red light phototherapy (3/3): Hair regrowth, Pain reduction, Wound healing and Practical applications”

  1. Ever since I read this 3 articles, I have been trying to by me a GU10 red LED bulb. But I just can’t find them in my country (Portugal). Even in Amazon I won’t find anything that will be sent here (lots of items are not shipped to Portugal). The only thing I find are meters of fairy Xtmas leds!
    As silly as it may seem, do you think that would be an option to put in a bedroom?
    (My main concern is the trouble I have on getting sleepy)

    • Hi Ana, the fairy lights are better than nothing as long as you turn other lighting down or off. If you can get gu10 try normal light bulbs in table lamps. You should be able to get red light bulbs for them. Use them in your house in the evening. Have you looked at our blog post on sleep? Check it out for other tips. Hope you sleep better now!


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