The Science of Natural Healing
Three natural signals shape how your body repairs and rests. Light that fuels your cells. The Earth's electrical charge. The daily rhythm of sunlight. Choose a topic to see how each one works and what the research really shows.
How to read this library. Every benefit below carries a label that tells you the type of evidence behind it. Meta analysis pools many controlled trials. Clinical trial means at least one controlled human study. Pilot study means small or early human research. Guideline means an expert medical body has issued a recommendation. Full references are at the bottom of each topic.
What is Red Light Therapy?
Red light therapy is the everyday name for photobiomodulation or PBM. It uses low levels of red and near infrared light to trigger natural processes inside your cells. It contains no UV. It does not tan or burn. It is not a heat treatment.
Endre Mester in Hungary first noticed light speeding up hair growth and healing
Placebo controlled trials pooled in one knee pain meta analysis
Patients covered in a 2024 hair loss review of light therapy
Volunteers in a controlled trial measuring collagen density
How It Works Inside Your Cells
Scientists are still refining the full picture. This is the leading explanation supported by decades of laboratory research.
Light Is Absorbed
Red and near infrared light pass into the skin. Inside your mitochondria an enzyme called cytochrome c oxidase absorbs these wavelengths. It is a key step in how cells make energy.
A Brake Is Released
In stressed cells nitric oxide can bind to this enzyme and slow it down. Light appears to knock the nitric oxide loose so the energy chain can run freely again.
Energy Rises
The cell produces more ATP. This is the fuel behind repair and renewal. The released nitric oxide can also relax nearby blood vessels.
Repair Signals Switch On
A brief and gentle signalling pulse tells the cell to activate protective and repair genes. In stressed tissue research shows oxidative stress and inflammation markers tend to fall.
One interesting detail. Light tends to help cells that are stressed or damaged far more than healthy cells that are already working well. That is one reason results vary between people.
Each Colour Has A Different Job
The colour of light is measured in nanometres (nm). Different wavelengths are absorbed by different targets and reach different depths.
Red
Absorbed mostly in the skin and the tissue just below it. The most studied band for collagen and skin texture and fine lines.
Best for · skin tone · fine lines · surface healing
Near Infrared
Invisible to the eye. It scatters less than red so more of it travels deeper toward muscle and joints. The 785 to 860nm range is the one used in knee pain research.
Best for · muscles · joints · recovery
Blue
Works differently to red. Acne bacteria make natural compounds called porphyrins that absorb blue light strongly. The reaction damages the bacteria. It reaches only about 0.3mm into skin.
Best for · breakouts · oily skin
Yellow
Sits between green and red. It has a smaller evidence base than red or blue. It is mostly used in facial devices for redness and an even looking skin tone.
Best for · redness · sensitive skin
Why devices skip 700 to 780nm. This range lines up with a dip in what cytochrome c oxidase absorbs. Research has found it to be rather ineffective. That is why quality devices pair a red peak near 660nm with a near infrared peak near 850nm.
An honest note on depth. You may see claims that infrared reaches 5cm into the body. Real measurements show most light is absorbed within the first few millimetres of skin. Near infrared carries a useful share further than red does. That is enough to reach many muscles and joints but depth claims online are often exaggerated.
More Is Not Always Better
Light therapy follows what scientists call a biphasic dose response. A low to moderate dose stimulates repair. Too much can cancel out the benefit. Consistency matters more than marathon sessions.
Irradiance
How strong the light is at your skin. Measured in mW/cm². It drops quickly as you move away from the device. Distance is part of your dose.
Energy Dose
How much light you received in total. Measured in J/cm². It equals irradiance multiplied by time. For example 50 mW/cm² for 10 minutes gives 30 J/cm².
Frequency
How often you use it. Most studies use 3 to 5 sessions a week over 8 to 12 weeks. The skin trial above used two sessions a week for 30 sessions.
What Red Light Can Do
Here is what controlled research has found so far. We have listed the strongest areas first.
Joint Pain
A review of 22 placebo controlled trials in knee osteoarthritis found that recommended doses reduced pain compared with placebo. The benefit was still present weeks after treatment ended.
Stausholm 2019 · BMJ Open · 1 063 patients
Hair Density
Across 38 studies light therapy increased hair density in pattern hair loss compared with placebo. Benefits were seen in both men and women. Several home devices are FDA cleared for this use in the USA.
Perez 2024 · Dermatologic Surgery · 3 098 patients
Muscle Performance
Trials in athletes and active people show improved endurance and less exercise related muscle damage. Effects are strongest when light is used before training. Researchers have mapped a clear dose window.
Leal Junior 2019 · based on 39 controlled trials
Skin & Collagen
Twice weekly sessions over 30 treatments improved skin roughness and complexion. Ultrasound scans showed higher collagen density compared with untreated controls.
Wunsch & Matuschka 2014 · 136 volunteers
Breakouts
Combining blue (415nm) and red (660nm) light reduced inflammatory acne lesions by 76% in one trial. Blue alone gave 58% and white light 25%.
Papageorgiou 2000 · British Journal of Dermatology
Mouth Healing
The international cancer supportive care body MASCC/ISOO recommends light therapy to help prevent painful mouth sores in certain cancer treatments. This is clinical use under medical care.
Zadik 2019 · Supportive Care in Cancer
Sleep
Twenty elite basketball players received 30 minutes of whole body red light each evening for 14 days. Sleep quality scores and blood melatonin improved compared with the untreated group.
Zhao 2012 · Journal of Athletic Training · 20 athletes
Brain & Focus
Near infrared applied to the head is being studied for focus and brain health. Results are promising but most human studies are still small. We will update this as research grows.
NIA workshop 2023 · research overview
Inflammation
Reviews of laboratory and animal research show light can lower inflammatory markers in stressed tissue. This likely sits behind many of the benefits above.
Hamblin 2017 · AIMS Biophysics
Building Your Routine
Always follow the guide that comes with your Suēle device. These are general ranges drawn from the research.
| Goal | Wavelength | Session | How often | When to expect change |
|---|---|---|---|---|
| Skin tone and fine lines | 660nm | 10 to 15 min | 3 to 5 times a week | 4 to 12 weeks |
| Breakouts | 415nm plus 660nm | 10 to 15 min | 3 times a week | 4 to 8 weeks |
| Muscle recovery | 850nm | 10 to 20 min | Before training | From the first weeks |
| Joint comfort | 850nm | 10 to 20 min | 3 to 5 times a week | 2 to 6 weeks |
| Hair | 630 to 660nm | As directed | 3 times a week | 16 to 26 weeks |
Clean Bare Skin
Remove makeup and sunscreen first. Clothing and thick creams block light.
Mind The Distance
Panels work at the distance stated in the manual. Moving back reduces your dose a lot.
Stay Consistent
Results build over weeks. Short regular sessions beat long occasional ones.
Use It Wisely
Red light therapy has a very good safety record when used as directed. Mild warmth or temporary redness are the most common reports. Speak to your doctor first if any of these apply to you.
Check With Your Doctor If
- You are pregnant or breastfeeding
- You take medicine that makes skin sensitive to light such as some antibiotics or acne tablets or St John's Wort
- You have light sensitive epilepsy or migraines
- You have cancer or an unexplained mole or lesion in the treatment area
- You have lupus or another light sensitive condition
Protect Your Eyes
- Never stare directly into bright LEDs
- Use the goggles supplied with panels and lamps
- Near infrared is invisible so your eyes do not blink it away
- Masks are designed for closed eyes. Keep them shut during sessions
Clearing Up Common Myths
"Longer sessions mean faster results"
Not true. Benefits follow a dose curve. Past a point extra time can reduce the effect.
"It feels hot so it must be working"
PBM is not a heat treatment. Good devices feel only gently warm.
"It is like a tanning bed"
Tanning beds use UV light. Red and near infrared contain no UV and do not tan or damage DNA.
"Any red bulb will do"
Results depend on the right wavelength and enough power at the skin. A coloured party bulb delivers neither.
Frequently Asked
Is red light therapy safe?
For most adults yes. It uses non ionising light with no UV. Reported side effects are rare and mild such as brief redness. Read the safety section above if you are pregnant or take light sensitising medicine.
How long until I see results?
Muscle recovery can improve within the first few weeks. Skin changes usually take 4 to 12 weeks. Hair takes the longest at around 4 to 6 months.
Can I use it every day?
Many people use it daily for short sessions. Research protocols usually use 3 to 5 sessions a week. Rest days are fine and do not undo your progress.
Should I use red or near infrared?
Red suits skin and surface concerns. Near infrared suits muscles and joints. Many Suēle devices combine both so you cover both depths in one session.
Can I use skincare with it?
Use it on clean skin then apply your serums and moisturiser afterwards. Avoid using it straight after strong acids or retinoids if your skin is sensitive.
Is it the same as an infrared sauna?
No. Saunas heat the body. Red light therapy delivers specific wavelengths at low power to act on cells without heating them.
Are Suēle devices medical devices?
Suēle devices are wellness products for home use. They are not intended to diagnose treat or cure any disease. Medical conditions should always be managed with your healthcare provider.
Ready to Experience Light Therapy?
Panels and lamps and masks and wraps for every routine.
Shop Red Light Therapy- de Freitas LF & Hamblin MR (2016). Proposed mechanisms of photobiomodulation. IEEE J Sel Top Quantum Electron. Read
- Hamblin MR (2017). Mechanisms and applications of the anti inflammatory effects of photobiomodulation. AIMS Biophysics. Read
- Huang YY et al (2009). Biphasic dose response in low level light therapy. Dose Response. Read
- Esnouf A et al (2007). Depth of penetration of an 850nm laser in human skin. Acupunct Electrother Res. Read
- Stausholm MB et al (2019). Low level laser therapy in knee osteoarthritis. BMJ Open. Read
- Perez SM et al (2024). Low level laser and LED therapy in alopecia. Dermatologic Surgery. Read
- Leal Junior ECP et al (2019). Recommendations for photobiomodulation in exercise performance and recovery. Braz J Phys Ther. Read
- Wunsch A & Matuschka K (2014). Red and near infrared light for skin and collagen density. Photomed Laser Surg. Read
- Lasers and light treatments for acne vulgaris: promising therapies (2010 review). J Clin Aesthet Dermatol. Read
- Zadik Y et al (2019). Photobiomodulation for oral mucositis. MASCC/ISOO guidelines. Read
- Zhao J et al (2012). Red light and sleep quality in female basketball players. J Athl Train. Read
- NIA workshop report (2025). Mechanisms and applications of photobiomodulation. Read
What is Grounding?
Grounding (also called earthing) means direct skin contact with the Earth's surface. You can do it barefoot on grass or sand. You can also use conductive sheets and mats that connect to the earth indoors. For most of history humans lived this way. Modern shoes and raised beds and buildings have largely separated us from the ground.
Published human studies on grounding to date
People in a 2025 double blind trial using real or fake mats
Men in a sham controlled study on muscle recovery
Reported risk when used safely and as directed
How Grounding May Work
The proposed mechanism is still being studied. Here is the idea researchers are testing.
Contact
Bare skin touches a conductive surface such as damp soil or sand or the sea. Indoors a grounding product links you to the earth wire of your home or a ground rod.
Equalising
The Earth's surface holds a vast supply of free electrons. On contact your body settles to the same electrical potential as the ground.
Antioxidant Effect
Researchers propose these electrons may help neutralise free radicals at sites of inflammation. This part of the theory has not yet been directly proven in humans.
Calmer Systems
Studies have measured shifts in cortisol and blood cell behaviour and markers of muscle damage. These hint at a calmer nervous system and lower inflammation.
What Grounding May Do
Grounding research is younger and smaller than red light research. Here is each key study and what it actually measured.
Sleep Duration
Sixty adults used a real or identical fake grounding mat for 6 hours a day for 31 days. Neither group knew which they had. Sleep trackers showed the grounded group slept longer. Questionnaire scores for sleep quality and stress did not differ.
Korea 2025 · double blind · 60 people
Muscle Recovery
After a hard eccentric workout 32 young men slept grounded or on sham sheets. The grounded group had less creatine kinase leaking from muscle. This marker suggests less muscle damage.
Brown 2015 · sham controlled · 32 men
Sleep in Older Adults
In people with mild Alzheimer's disease 30 minutes on a grounding mat five times a week improved sleep quality in a double blind trial.
Taiwan 2022 · double blind
Cortisol Rhythm
Twelve people with poor sleep and stress slept grounded for 8 weeks. Night time cortisol dropped and daily cortisol patterns moved toward a normal rhythm. Most reported better sleep and less pain.
Ghaly & Teplitz 2004 · 12 people
Blood Flow
After 2 hours of grounding the surface charge on red blood cells rose about 2.7 times and cells clumped together less. Higher charge helps cells repel each other which may support smoother flow.
Chevalier 2013 · 10 people
Inflammation
A research review describes changes in white blood cells and inflammation markers and reports faster recovery in case studies of slow healing wounds.
Oschman 2015 · Journal of Inflammation Research
Our honest take. Grounding studies are encouraging but most are small. Much of the early research was carried out by scientists linked to grounding product companies. Independent double blind trials have only recently begun and their results so far are positive but modest. We think grounding is a low risk practice that is worth trying. We will not promise it cures anything.
Ways to Ground Yourself
Walk Barefoot
Grass or soil or wet sand for 20 to 30 minutes. Moist ground conducts best. Dry tar and wooden decks do not conduct.
Swim or Wade
The sea and lakes are highly conductive. A walk along the waterline grounds you well.
Grounding Sheets
Sleep connected for 7 to 8 hours a night. This is the longest daily exposure most people can get.
Desk Mats
Rest bare feet or wrists on a mat while you work. It adds grounded hours to a day spent indoors.
Ground Safely
Indoor Products
- Check that your plug socket is properly earthed. A plug in socket tester costs little and gives peace of mind
- Only connect to the earth pin using the cord supplied. Choose cords with a built in safety resistor
- Unplug during lightning storms
- Outside the home a ground rod in damp soil is an alternative
Speak To Your Doctor If
- You take blood thinning medicine since some researchers advise monitoring
- You take medicine for blood pressure or blood sugar and notice changes
- You have a pacemaker or other implanted electrical device
- You are managing any medical condition
Frequently Asked
Is grounding scientifically proven?
Not fully. Small studies and a few double blind trials show measurable changes in sleep and cortisol and recovery markers. Larger independent trials are still needed. We share the research openly so you can decide for yourself.
Does a grounding sheet really connect to the earth?
Yes. It plugs into only the earth pin of a correctly wired socket. That pin runs to a rod in the ground under your home. No mains electricity passes through the sheet.
How long should I ground for?
Studies range from 30 minutes a day to a full night of sleep. Sleeping grounded is the easiest way to get many hours.
Will load shedding or outages affect it?
No. The earth connection works whether the power is on or off because it carries no electricity.
Why do I feel tingling?
Some people notice mild tingling or warmth in the first days. It usually fades. In one trial people on fake mats reported it too so it is not always a sign of the effect.
Can I combine grounding with red light therapy?
Yes. They work through different pathways. A red light session in the morning and a grounded night of sleep fit together easily.
- Ghaly M & Teplitz D (2004). Grounding during sleep and cortisol. J Altern Complement Med. Read
- Brown D et al (2010). Pilot study on grounding and delayed onset muscle soreness. J Altern Complement Med. Read
- Brown R et al (2015). Grounding after eccentric contractions reduces muscle damage. Open Access J Sports Med. Read
- Chevalier G et al (2013). Earthing reduces blood viscosity. J Altern Complement Med. Read
- Oschman JL et al (2015). Grounding and inflammation and wound healing. J Inflamm Res. Read
- Chevalier G et al (2012). Earthing: health implications of reconnecting to the Earth's surface electrons. J Environ Public Health. Read
- Randomized double blind placebo controlled study on sleep with an earthing mat (2025). Read
- Miller DJ & Gupta CC (2025). What is grounding and could it improve sleep? The Conversation via Daily Maverick. Read
Your Body Clock
Deep in your brain a tiny master clock keeps time for nearly every organ. It times your sleep and hormones and body temperature and digestion. Light reaching your eyes is the strongest signal that keeps this clock set to the right time. Circadian lighting means using the right light at the right time of day.
Peak sensitivity of melanopsin the light sensor that sets your clock
Melatonin time lost to ordinary room light in the evening
Minimum daytime melanopic lux recommended by experts
Maximum evening melanopic lux in the 3 hours before bed
How Light Sets Your Clock
Special Eye Cells
Besides the cells you see with your eyes also contain cells called ipRGCs. They hold a light sensor called melanopsin that is most sensitive to blue light near 480nm.
A Direct Line
These cells send signals straight to your brain's master clock. They do not help you see. Their job is to tell your body whether it is day or night.
Morning Moves You Earlier
Bright light in the morning shifts your clock earlier. You feel sleepy at a sensible hour and wake more easily.
Evening Pushes You Later
Bright and blue rich light at night delays your clock and suppresses melatonin. This is the hormone that prepares you for sleep.
What The Research Shows
Room Light Steals Your Night
Researchers compared normal room light (under 200 lux) with dim light (under 3 lux) before bed. Room light delayed melatonin onset in 99% of people and cut its duration by about 90 minutes. Light during sleep hours suppressed melatonin by more than half in most cases.
Gooley 2011 · Journal of Clinical Endocrinology & Metabolism · 116 adults
Expert Light Targets
In 2022 an international panel of circadian scientists published the first consensus targets for healthy indoor light. They use a measure called melanopic EDI which counts light the way your clock sensors see it.
Brown 2022 · PLOS Biology
| Time of day | Expert target | What it looks like |
|---|---|---|
| Daytime | At least 250 melanopic lux at eye level | Bright daylight or bright cool white light. Typical offices often fall short. An overcast sky outside gives around 1 000 lux |
|
Evening 3 hours before bed |
No more than 10 melanopic lux | Dim warm amber or red toned lamps placed low. Overhead bright white lights off |
| Sleep | No more than 1 melanopic lux | As dark as possible. Blackout curtains and no glowing screens |
Why warm and red light suit the evening. Melanopsin responds most to blue light around 480nm and far less to long amber and red wavelengths. So a dim warm lamp lets you see comfortably while sending a much weaker daytime signal to your clock. Brightness still matters. Even warm light should be kept low before bed.
A Day In Natural Rhythm
Here is how light therapy and grounding and circadian lighting fit together across one day.
Frequently Asked
Is blue light bad for me?
No. Blue light during the day is helpful. It boosts alertness and anchors your clock. The issue is bright blue rich light late at night when your body expects darkness.
Do blue light glasses help?
They can lower the signal from screens in the evening. Dimming your room lighting and screens often makes a bigger difference.
Is red light therapy fine at night?
Red light affects melanopsin far less than white or blue light. Therapy devices are bright though so we suggest finishing sessions at least an hour before bed and keeping your eyes closed or covered.
What if I work shifts?
Treat your wake time as your morning and your bedtime as your night. Seek bright light early in your shift and keep light dim on the way home. Speak to your doctor about a plan for long term shift work.
What makes a lamp circadian friendly?
It should give warm low light in the evening with little blue content. Look for lamps that shift from bright daylight tones to amber and red so one lamp serves your whole day.
Light Your Home The Natural Way
Lighting for brighter days and calmer evenings.
Shop Circadian Lighting- Foster RG et al (2020). Circadian photoentrainment in mice and humans. Biology. Read
- Review (2016). The importance of ipRGCs for health and lighting design. J Solid State Lighting. Read
- Gooley JJ et al (2011). Room light before bedtime suppresses melatonin. J Clin Endocrinol Metab. Read
- Brown TM et al (2022). Recommendations for daytime and evening and nighttime indoor light exposure. PLOS Biology. Read
- CIE Technical Note 015 (2023). Light exposure recommendations explained. Read
This library is for general education. It is not medical advice. Suēle products are wellness devices and are not intended to diagnose treat cure or prevent any disease. Research findings describe study results and individual experiences vary. Speak to a qualified healthcare professional before starting any new wellness practice especially if you are pregnant or have a medical condition or take prescription medicine.