Red Light Therapy for Fatigue & Afternoon Energy

About the author

Evelyn Reed, M.S.

Health Science EducatorCertified Wellness Coach

Evelyn Reed, M.S., is a Health Science Educator and Certified Wellness Coach specializing in evidence-based, at-home wellness solutions. With a Master's degree in Health Science, she focuses on translating complex scientific research on cellular health and light therapy into practical, accessible protocols. Evelyn is dedicated to empowering individuals to manage pain, improve sleep, and enhance skin vitality. Her science-first, empathetic approach makes her a trusted advocate for achieving long-term health goals.

Afternoon fatigue can feel like hitting a wall. You may start the day focused and productive, only to feel your energy evaporate somewhere between lunch and early evening. For some people, especially those living with chronic fatigue, ME/CFS, fibromyalgia, or post-viral conditions like long COVID, that “afternoon crash” is more than an annoyance; it can derail the entire day.

As a red light therapy wellness specialist and health advocate, I have worked with many people who are searching for gentle, at-home ways to feel more awake, less achy, and more mentally clear in the second half of the day. Red light therapy is one of the tools many are curious about. The science is promising in some areas, limited or mixed in others, and often misunderstood online.

This article walks through what we actually know about red light therapy and fatigue, how it might fit into a broader strategy for afternoon energy, and where to be cautious. I will reference reputable medical sources such as Cleveland Clinic, WebMD, GoodRx, the ME Association, and peer-reviewed research so you can make informed decisions rather than relying on hype.

Why Afternoon Fatigue Happens

Most people recognize a natural dip in energy in the midafternoon. Our internal circadian rhythm shifts slightly, digestion and blood flow change after lunch, and long periods of sitting or screen time build up mental and physical fatigue. For many, this “slump” is mild and improves with movement, hydration, or better sleep habits.

For others, especially those dealing with chronic fatigue syndrome (also called ME/CFS), fibromyalgia, or post-viral fatigue, the afternoon can feel like the point where their system simply runs out of power. Research summarized by Koze Health and several chronic fatigue resources describes chronic fatigue as more than just being tired: it is a long-term state of overwhelming exhaustion not relieved by rest, often accompanied by brain fog, muscle and joint pain, unrefreshing sleep, and dizziness when standing.

Many researchers suspect that problems with cellular energy production, particularly in the mitochondria (the “powerhouses” inside cells), contribute to this type of fatigue. Studies and feasibility trials referenced by the Quadram Institute, the ME Association, and others are exploring whether targeted light, including red light, can support these energy systems and change how people experience fatigue. The key question for you is whether this approach can help your own afternoon slump, and if so, how to use it thoughtfully.

What Red Light Therapy Actually Is

Red light therapy, often called photobiomodulation or low-level light therapy, uses low-level red and near-infrared light to influence cellular function without heating or burning the skin. Sources such as Cleveland Clinic, WebMD, and News-Medical explain that medical and wellness devices typically use wavelengths in roughly two bands:

Red light in the range of about 600–700 nanometers tends to penetrate the more superficial layers of skin. It is often used for skin rejuvenation, improving collagen, and treating conditions such as acne, psoriasis, and certain scars.

Near-infrared light in the range of about 800–850 nanometers (sometimes extending up to 900–1000 nanometers in medical settings) penetrates more deeply into muscles, joints, and other tissues. This range is often used for pain relief, recovery, and deeper tissue support.

The technology has roots in NASA experiments that used red and near-infrared light to support wound healing and recovery in astronauts. Over time it has expanded into dermatology, sports recovery, pain management, and consumer wellness. Devices range from handheld wands and face masks to full-body panels and beds. Medical-grade devices are usually more powerful and tightly controlled, while at-home systems trade some power and precision for convenience.

Cleveland Clinic and WebMD both emphasize an important point: red light therapy is promising but still an emerging therapy. The strongest evidence so far is for certain skin conditions, aspects of pain, and some sports recovery outcomes. For many other claims, including energy, mood, and sleep, data are encouraging but incomplete, and more rigorous trials are needed.

How Red Light Therapy Might Help an Afternoon Energy Slump

Red light therapy is not a stimulant like caffeine. It does not “force” your body to be awake. Instead, it appears to nudge underlying systems that impact energy, recovery, and sleep. For afternoon fatigue, three mechanisms are particularly relevant.

Mitochondria and Cellular Energy

Multiple sources, including Koze Health, Prism Light Pod, and scientific reviews summarized by News-Medical and UCLA Health, describe a shared mechanism: red and near-infrared light are absorbed by components within mitochondria, especially an enzyme called cytochrome c oxidase. This interaction can increase production of ATP, the main energy currency inside cells.

Chronic fatigue resources and functional medicine clinics often frame afternoon exhaustion as the visible result of low cellular energy. From that perspective, if red light therapy can gently increase ATP production and improve mitochondrial efficiency, it could theoretically translate into more stable, sustainable energy later in the day. People with chronic fatigue, ME/CFS, or post-viral fatigue sometimes report that, over weeks of regular use, they feel less “crashed” in the afternoon and more capable of light activity.

However, those subjective reports sit on top of a still-developing evidence base. A feasibility N-of-1 trial of bright and dim light therapy for fatigue (reported in PubMed Central) found that both bright and dim light, delivered through wearable glasses, were associated with small but statistically significant reductions in self-reported fatigue. Only a minority of participants experienced clear benefit, and some actually felt worse. This pattern suggests that light-based interventions can help some people but not everyone, and that individual responses vary widely.

Inflammation, Pain, and “Heavy” Muscles

Many people describe afternoon fatigue less as simple sleepiness and more as a feeling of heaviness, soreness, or flu-like malaise. Chronic pain conditions such as fibromyalgia and arthritis often flare later in the day, making movement and concentration harder.

Multiple sources, including Cleveland Clinic, WebMD, Laguna Heights Dental, Prism Light Pod, and Clinic 5C, highlight red light therapy’s anti-inflammatory and tissue-healing effects. Mechanistic research indicates that red and near-infrared light can improve blood flow, increase nitric oxide availability, and modulate inflammatory pathways. Clinical and wellness reports show potential reductions in muscle soreness, joint stiffness, and pain in conditions such as arthritis, fibromyalgia, and post-surgical recovery.

If your afternoon slump is partly driven by pain or residual soreness from earlier activity, a timed red light session may help reduce that burden, making your body feel lighter and more capable. Some chronic fatigue and fibromyalgia resources note that people report less pain, better flexibility, and improved mood after a series of treatments, though results are not universal.

Sleep, Circadian Rhythms, and Timing Your Light

Sleep quality heavily shapes how you feel at 3:00 PM. Poor or fragmented sleep amplifies afternoon fatigue, no matter what you do. Light is one of the most powerful regulators of your body’s clock, which is why timing of red light exposure matters.

GoodRx and the Sleep Foundation explain that blue light, such as that from screens and cool white bulbs, strongly suppresses melatonin and shifts circadian rhythms, while red or amber light has a much weaker effect. That is why dim red-tinted lamps are often suggested as nighttime options that are less likely to disrupt sleep.

However, when we move from simple red-tinted lamps to red light therapy devices with specific wavelengths and higher intensities, the picture becomes more complex. GoodRx reviews mixed sleep research and notes that some small studies suggest red light may improve melatonin levels and sleep quality, while other studies report more awakenings and negative emotions in people using red light at night.

A randomized trial reported in PubMed Central that tested pre-bedtime red light in both healthy adults and people with insomnia disorder found that red light increased subjective alertness and negative emotions compared with darkness or white light. In some cases it shortened the time it took to fall asleep but worsened sleep continuity and anxiety. The authors urged caution in treating red light as automatically “sleep friendly.”

At the same time, a systematic review in Nature looking at bright light (not necessarily red) for shift workers found that carefully timed light exposure with medium intensity, often at night, increased total sleep time after shifts by roughly half an hour and modestly improved sleep efficiency. That suggests that light used at the right time can shift circadian rhythms and improve fatigue and sleep in specific contexts.

For afternoon fatigue, this all points in a similar direction: red light therapy may be more useful as a daytime or early-afternoon support for cellular energy and alertness than as a light you rely on late at night. Using moderately intense red or near-infrared light earlier in the day, then prioritizing darkness or very dim, warm light in the evening, is a more evidence-aligned strategy than flooding your bedroom with bright red light at bedtime.

What Does the Evidence Actually Say About Fatigue?

Red light therapy is being studied in a range of fatigue-related conditions, from chronic fatigue syndrome to fibromyalgia, shift work, and post-viral states. The details matter because they shape realistic expectations.

Chronic Fatigue, ME/CFS, and Post-Viral Fatigue

Articles from Koze Health, Prism Light Pod, Pulse Laser Relief, Red Light Therapy Center, and Sheen Vein & Cosmetics describe a consistent set of ideas. Chronic fatigue syndrome or ME/CFS is a long-term condition marked by severe fatigue not relieved by rest, along with brain fog, pain, and unrefreshing sleep. Proposed contributors include mitochondrial dysfunction, immune dysregulation, hormone imbalances, and post-viral changes.

Red light therapy is hypothesized to help ME/CFS and chronic fatigue by boosting mitochondrial ATP production, reducing inflammation and oxidative stress, improving circulation, and gently influencing immune signaling. There is indirect support from studies in fibromyalgia and related conditions that show reductions in pain and improvements in quality of life with low-level laser or light therapy.

Importantly, the ME Association, a patient-focused medical charity, reviews the evidence and concludes that for ME/CFS there is currently no reliable proof from well-conducted, placebo-controlled trials that red light therapy is effective or even fully safe long term for this specific condition. They state that short-term use under medical supervision appears safe but explicitly do not recommend that people with ME/CFS spend money on red light therapy as a treatment at this time because of the evidence gaps.

The Quadram Institute’s Light ME Up pilot study illustrates where the field is going. Ten people with ME are being given a red light to use at home for two minutes per day over two weeks, with symptoms monitored before and after. This study is testing feasibility and objective outcome measures rather than claiming established benefit. It represents early, careful exploration, not a finished answer.

For someone with chronic fatigue or ME/CFS who experiences severe afternoon crashes, red light therapy should therefore be viewed, at best, as an experimental adjunct used alongside established strategies such as pacing, sleep optimization, pain management, and psychological support. It is not a proven treatment, and for ME/CFS specifically, medical charities urge caution about spending significant money on it.

Sleep, Mood, and Red Light

Sleep-focused sources, including GoodRx, Crew Chiropractic, Calm, and the Sleep Foundation, emphasize that red or red-tinted lighting is generally less disruptive than blue light at night, but that does not mean red light therapy reliably improves sleep. Evidence is mixed and comes from small, varied studies.

Some small trials, including those in athletes, have reported that whole-body red light sessions before bed improved nighttime melatonin levels, sleep quality, and next-day energy. Another trial reported that prolonged red light exposure during sleep reduced sleep inertia (morning grogginess) and improved immediate performance on waking.

Balanced against that, GoodRx describes a study in more than one hundred people in which those using red light therapy woke more frequently during the night and experienced more negative emotions, including anxiety. The larger insomnia trial from PubMed Central echoes this concern, showing increased alertness and negative emotions with nighttime red light compared with darkness. The authors suggest that nighttime red light can worsen both mood and sleep for some people.

The Sleep Foundation and GoodRx converge on a conservative take: the best “light” for sleep is still darkness. If you need light at night, dim red or amber sources are less likely to suppress melatonin than bright white or blue light, but red light therapy devices should be considered experimental for sleep, with careful monitoring of your own responses.

From an afternoon fatigue perspective, these findings suggest that daytime and early evening red light exposure might be more appropriate if your goal is to feel more awake and less sore without disturbing nighttime sleep.

Light Therapy for Fatigue in Daily Life

Beyond specific diagnoses, some broader light therapy studies touch on everyday fatigue. The N-of-1 crossover trial of bright and dim light therapy for fatigue symptoms, delivered via wearable glasses and followed virtually, is particularly relevant.

In that trial, both bright light and dim light produced small but statistically significant reductions in fatigue across participants when compared with usual care. However, responses were highly individual. Only a small fraction of participants found that both bright and dim light reduced their fatigue. Many found that only one form of light helped, and the majority did not experience meaningful benefit from either. A notable minority actually felt more fatigued during light therapy periods.

Participants generally rated the light therapy program as easy to use and helpful overall, but some found the light glasses difficult to wear or operate, and survey burden was a challenge. The takeaway is that even when average results look modestly positive, individual responses can range from very helpful to clearly unhelpful.

For your afternoon energy, that means red light therapy is best approached as something to test gently and personally, not as a guaranteed fix. It may help you feel more stable and less fatigued, or it may have little effect, or occasionally even worsen symptoms. Careful self-monitoring is crucial.

Potential Benefits vs Evidence Strength

A brief comparison can help clarify what is reasonably supported and what remains speculative.

Goal in the Afternoon	How Red Light Therapy Might Help	Evidence Strength So Far	Key Sources Mentioned
Feel less drained and more steady	Support mitochondrial ATP production and cellular recovery, possibly stabilizing energy over time	Early and indirect; small trials and observational reports, especially in chronic fatigue contexts	Koze Health, Prism Light Pod, Red Light Therapy Center, News-Medical
Reduce pain and “heaviness”	Lower inflammation, improve blood flow, support tissue repair and muscle recovery	Moderate for some pain conditions, fibromyalgia, and sports recovery; still emerging	Cleveland Clinic, WebMD, News-Medical, fibromyalgia resources
Improve afternoon focus and brain fog	Possible improvements in cerebral blood flow and neuroinflammation; some trials in brain injury and dementia show cognitive benefits	Early research; promising but not specific to afternoon fatigue	UCLA Health, WebMD, chronic fatigue and fibromyalgia articles
Sleep better at night after using RLT in the day	Indirect support through better pain control and circadian support; mixed results from nighttime red light trials	Mixed and limited; some positive, some negative; no standard protocol	GoodRx, Crew Chiropractic, Calm, PubMed Central trials
Quickly erase an afternoon crash like a stimulant	Short-term subjective energizing effect for some; may increase alertness	Not established as a reliable “quick fix”; responses are highly variable	N-of-1 fatigue trial, insomnia trial, GoodRx review

Practical Ways to Use Red Light Therapy for Afternoon Fatigue

If you decide to experiment with red light therapy as part of your afternoon fatigue toolkit, it is important to ground your routine in what we know and to respect what we do not yet know.

Choosing a Device Thoughtfully

Evidence-based articles from Cleveland Clinic, WebMD, News-Medical, Koze Health, and Prism Light Pod agree on a few fundamentals when selecting a red light device for energy and recovery:

Aim for devices that use both red and near-infrared wavelengths in ranges commonly studied for tissue repair and fatigue. Many wellness and chronic fatigue sources highlight red light around 630–660 nanometers and near-infrared light around 810–850 nanometers as practical targets. Some chronic fatigue providers also look for power outputs in the range of roughly 20–50 milliwatts per square centimeter, which is moderate and designed for at-home use rather than high-intensity medical lasers.

Consider the treatment area you care about. If your afternoon fatigue is whole-body and accompanied by widespread pain, a panel or bed that exposes larger areas may make more sense than a tiny facial device. Wellness centers often use full-body red light pods or beds for people with chronic fatigue, fibromyalgia, and widespread pain, while smaller panels can work for home users who are consistent.

Prioritize safety and quality. Look for devices that are described as FDA-cleared for specific purposes when possible, and be cautious of vague “FDA approved” or “medical grade” language used in marketing. WebMD and UCLA Health emphasize following manufacturer instructions, including eye protection. If you have darker skin tones or a history of hyperpigmentation, dermatology organizations recommend consulting a dermatologist before starting facial red light treatments.

Whenever possible, discuss device choice with a healthcare provider who understands your medical history, medications, and any light-sensitive conditions. People using photosensitizing medications, such as some antibiotics, oral contraceptives, acne drugs, diuretics, and antihistamines, should be particularly careful, as noted by GoodRx.

Timing and Duration for an Afternoon Focus

Published protocols for chronic fatigue, CFS, and related conditions often recommend sessions in the range of 10–20 minutes per area, three to five times per week. Koze Health describes such schedules for people with chronic fatigue, and Prism Light Pod and other wellness clinics echo session lengths of about 10–20 minutes.

For an afternoon fatigue focus, many people do well starting with a modest program and then adjusting based on their responses. A practical pattern is to place sessions in the early to midafternoon, well before your typical bedtime. That might mean using your device sometime between early afternoon and late afternoon, depending on your schedule, rather than in the late evening.

Because some studies show that red light used close to bedtime can increase alertness or even worsen sleep and anxiety for certain people, keeping your red light therapy earlier in the day is a cautious and reasonable approach. This also aligns with the idea of providing an energy and recovery boost while still allowing your brain and body to wind down naturally in the evening.

In general, it is wise to start with shorter sessions and fewer days per week than device marketing may suggest, then build up slowly if you tolerate it well. It often takes at least two to four weeks of consistent use before people notice steady changes in energy or pain, and some chronic fatigue resources suggest that sleep and cognitive changes may take up to eight to twelve weeks.

Integrating Red Light With Other Healthy Habits

Red light therapy works best when it is one part of a broader plan rather than the only strategy you rely on. Chronic fatigue and fibromyalgia management plans described in clinical and patient resources consistently include pacing activities, improving sleep habits, supporting mental health, stress management, and gentle movement.

You can use your afternoon red light session as a structured pause. Some people treat it as a mini-reset: stepping away from screens, sitting or lying comfortably under the light, taking slow breaths, and then doing light stretching or a brief walk afterward. Others pair it with a short reflection on pacing for the rest of the day so they do not burn through any new energy immediately.

For people with chronic fatigue or ME/CFS, pacing remains essential even if red light therapy helps. The goal is to prevent post-exertional crashes, not to override the body’s limits. If you notice that feeling a bit better after a session tempts you to overdo things, consider planning gentle, predictable activities afterward instead of high-exertion tasks.

Risks, Limitations, and Who Should Be Cautious

Cleveland Clinic, WebMD, GoodRx, the ME Association, and News-Medical all stress that while red light therapy appears generally safe in the short term when used appropriately, there are important limitations.

Evidence limitations come first. Outside of some skin disorders, wound healing, certain types of pain, and aspects of sports recovery, red light therapy still lacks large, high-quality randomized trials. For fatigue, ME/CFS, chronic fatigue, and afternoon energy specifically, evidence is early and often indirect. Many claims you see online about guaranteed energy boosts, dramatic brain fog reversal, or cures for chronic illness are not backed by rigorous research.

Individual variability is significant. The N-of-1 fatigue trial and sleep studies show that some people benefit, some feel no difference, and some actually feel worse. This variability means you should monitor your own response carefully, especially if you have a complex medical history.

Short-term side effects are usually mild but possible. Reported issues include temporary redness, warmth, swelling, dryness, or itching of the skin in the treated area. These usually resolve when session length or frequency is reduced or paused. Overuse or using higher intensities than recommended can increase the risk of irritation.

Eyes require protection. Strong light, even in the red and near-infrared range, can potentially damage the retina if directed into the eyes. Medical and dermatology sources advise using appropriate eye protection that is compatible with the device and not staring directly into high-powered LEDs or lasers.

Certain groups need medical guidance. People with a history of skin cancer, eye disease, light-sensitive conditions, or those taking photosensitizing medications should consult a physician before starting red light therapy. Pregnant individuals should also ask their obstetric provider, as long-term safety data are limited even though some early data are reassuring.

For people with ME/CFS specifically, the ME Association’s current stance is that there is not yet enough high-quality evidence to recommend spending money on red light therapy as a treatment. If you choose to explore it, doing so in collaboration with a clinician and with realistic expectations is crucial.

An Example of an Afternoon Red Light Routine

To make this concrete, here is what an afternoon routine might look like when it is grounded in the available evidence and respectful of your body’s limits.

You might begin by choosing a consistent window during your workdays, perhaps soon after lunch or during the time you typically feel your energy start to dip. Rather than pushing through that slump with more caffeine, you set aside about twenty to thirty minutes for a restorative break that includes red light.

Before you start, you check in with your body and symptoms. If you are having a flare of pain or post-exertional malaise, you opt for a shorter session or skip it and focus on rest. If you feel stable enough, you position yourself comfortably in front of your device, making sure your eyes are protected according to the manufacturer’s instructions.

During the session, which may last about ten to twenty minutes depending on the device guidelines, you let the red or near-infrared light shine on areas that tend to feel heavy or sore, such as your back, legs, or shoulders. You breathe slowly, maybe listen to calming audio, and deliberately step away from emails and social media. This becomes a cue for your nervous system that it is allowed to shift toward a calmer, more restorative state.

After the session, rather than immediately jumping back into high-stress tasks, you give yourself a brief transition. That might be a glass of water, a light snack if needed, and a few minutes of gentle movement. Then you return to your afternoon with a clearer sense of how much energy you genuinely have and how you want to spend it, keeping pacing and self-compassion at the center.

Over several weeks, you track your afternoon energy, sleep quality, pain levels, and mood in a simple journal. This does not have to be elaborate; a few short notes each day are enough to see whether this routine seems to help, has no real effect, or coincides with worsening symptoms. If you do not notice meaningful benefit after a reasonable trial and you are using the device correctly, it may not be the right tool for you, and that is valuable information too.

Frequently Asked Questions About Red Light Therapy and Afternoon Fatigue

Is red light therapy a quick fix if I hit a 3:00 PM wall?

Red light therapy is not a quick stimulant in the way caffeine is. The research and clinical reports described by Cleveland Clinic, WebMD, Koze Health, and others suggest that potential benefits on energy, pain, and recovery tend to be cumulative and gradual, often emerging over weeks of consistent use. Some people do feel subjectively more awake or lighter after individual sessions, but that is not guaranteed, and it should not be used to override signals that you need rest.

Can I use red light therapy every afternoon?

Protocols for chronic fatigue and general wellness often suggest three to five sessions per week rather than daily use for everyone, with session lengths of about ten to twenty minutes per area. There is no universally agreed-upon “dose” for afternoon fatigue, and the systematic reviews highlight that dosing, intensity, and timing all matter. Starting with fewer sessions and building slowly while monitoring your response is safer than jumping straight into daily or multiple daily treatments.

What if I already have trouble sleeping at night?

If sleep is a challenge for you, it is especially important to be thoughtful about light timing. GoodRx, the Sleep Foundation, and the insomnia trial in PubMed Central all stress that darkness is still best for sleep, and that nighttime red light can worsen sleep or anxiety for some individuals. In that context, using red light earlier in the day and avoiding bright light of any color close to bedtime is more prudent. If you experiment with red light and notice that your evenings feel more wired or your sleep becomes more fragmented, step back and re-evaluate with your healthcare provider.

Feeling like your energy disappears halfway through the day can be discouraging, especially if you are already doing your best with sleep, nutrition, and stress management. Red light therapy offers a non-invasive, generally well-tolerated option that may support cellular energy, pain reduction, and recovery for some people, including those struggling with chronic fatigue. At the same time, the science is still catching up, and respected organizations urge caution, especially for ME/CFS.

If you choose to explore red light therapy for afternoon fatigue, think of it as a gentle experiment rather than a magic cure. Use credible devices, start slowly, protect your eyes and your sleep, and keep your broader health plan in view. Above all, listen to your body. Your experience, combined with evolving evidence, is the best guide to whether this therapy deserves a place in your afternoon routine.