Red Light Therapy & Clothing: What to Wear for Best Results

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.

Red light therapy can feel wonderfully simple: you turn on the panel, stand in front of it, and let the light do its work. Then a very practical question pops up: do you really need to take your clothes off, or will your leggings, T‑shirt, or underwear let enough light through?

As a red light therapy wellness specialist, I hear this concern often, especially from people using panels at home who care about modesty, warmth, and family privacy. Many have histories of body image struggles, chronic pain, or sensitive health conditions, and the last thing they want is a “wellness” routine that feels uncomfortable or unsafe.

This article walks you through what the science and expert guidance say about clothing and red light therapy. We will look at how the light actually interacts with fabric, where full clothing removal truly matters, when smart clothing choices are enough, and how to make sessions feel both effective and emotionally comfortable. Throughout, I will lean on evidence from clinical overviews such as Cleveland Clinic, research-focused explainers like Atria and Stanford Medicine, plus hands-on testing from sources including Light Therapy Insiders, Gembared, and several red light device brands.

This is education, not medical advice. If you have a medical condition, photosensitivity, or you are pregnant, please involve your healthcare provider in any decision about light therapy or exposing large areas of skin.

Why Clothing Matters More Than Most People Think

Clothing might seem like a minor detail, but for red light therapy it directly affects the dose your cells receive. To understand why, it helps to revisit how this therapy works.

How Red Light Therapy Works At A Cellular Level

Red light therapy, often called photobiomodulation or low-level light therapy, uses specific wavelengths of visible red and near-infrared light. Clinical sources such as Atria and Cleveland Clinic describe it this way:

Red light in the range of about 620 to 700 nanometers mainly affects the skin and just below the surface. Near-infrared light around roughly 800 to 1,000 nanometers reaches deeper tissues, including muscles and joints.

These photons are absorbed by parts of the cell, especially an enzyme in mitochondria often described as the cell’s “power plant.” Atria notes that this absorption can increase ATP (the cell’s energy currency), modulate oxidative stress, support antioxidant defenses, and release nitric oxide, which improves circulation. The net result in research has included better skin appearance, support for inflammatory skin conditions, wound healing, reduced musculoskeletal pain, and potentially improved hair growth.

Cleveland Clinic emphasizes that most promising evidence is for skin and some pain conditions, while many other claims remain under study. Stanford Medicine’s dermatology commentary similarly notes stronger support for hair regrowth and wrinkle reduction than for some of the more ambitious systemic promises. So red light is not magic, but it can meaningfully nudge biology in certain contexts—if enough light actually reaches the tissue you want to treat.

Why Bare Skin Changes The Dose You Actually Get

Light dose is usually described in terms of power density (milliwatts per square centimeter) and total energy (joules per square centimeter). Atria highlights a “Goldilocks” or biphasic effect: too little light does not do much, but too much exposure can actually reduce benefits. Typical guidance for at-home panels is something like 20 to 100 or more milliwatts per square centimeter at the skin, for about 5 to 20 minutes per treatment area, several times per week, with the body about 6 to 24 inches from the light.

Clothing sits directly in the path between the LEDs and your skin. Fabric can absorb, scatter, or reflect the light so that only a fraction of the original power density reaches the tissue. That means you can stand in front of a high-quality device and still deliver a much weaker, sometimes barely therapeutic dose to the cells you are trying to help.

For this reason, Atria and many device manufacturers explicitly recommend exposing bare skin and avoiding tight, thick, or dark garments during sessions. Articles from Infraredi, Lifepro, BlockBlueLight, and others all reinforce the same core message: direct skin exposure is ideal because fabric “blunts” the effect.

The nuance is that not all clothing behaves the same way. Some textiles allow a meaningful amount of light through, especially near-infrared, while others almost completely block it. That is where careful research becomes very useful.

What The Research Says About Clothes And Red Light

Multiple independent sources have tested how much red and near-infrared light can penetrate clothing. The results tell a consistent story: some benefit is possible through certain fabrics, but bare skin is far more reliable.

Wavelengths And Depth: Red Versus Near-Infrared

Several research overviews, including Atria, Infraredi, and Design and Health, note that:

Red light around 630 to 670 nanometers mainly penetrates a few millimeters into the skin. Near-infrared around 800 to 850 nanometers travels deeper, reaching tissues such as fascia, muscles, and joints.

Design and Health explains that clothing tends to interfere more with red light than with near-infrared. This matters for clothing removal decisions. If you are targeting deeper joint or muscle soreness with near-infrared, a very thin, light shirt might still allow a fraction of useful energy through, though reduced. If you are working on fine lines, acne, or superficial scars with red light, every layer of fabric makes it harder for enough photons to reach those skin cells.

A Lifepro article reported that red wavelengths around 670 nanometers can pass through common fabrics like cotton and polyester and still reach the skin, but with reduced intensity. Kineon and Design and Health both emphasize that while there may be some benefit through light, breathable fabrics, maximum effectiveness occurs when light reaches bare skin.

How Much Light Do Real Fabrics Block?

Light Therapy Insiders performed a detailed experiment using a handheld red and near-infrared device that delivered about 61 milliwatts per square centimeter at a distance of 3 inches with nothing in front of it. They then placed different fabrics between the light and a sensor to see how much power density remained. The numbers are eye-opening.

Here is a simplified snapshot of their findings when the barrier was held against the “skin” side (the sensor), not directly on the LEDs:

Barrier (against skin)	Approximate light reaching skin vs bare skin (single-device test)	Practical meaning
Thin black T‑shirt	About 2–3%	Very little of the original dose reaches the tissue.
Thick new white T‑shirt	About 54%	Just over half the light remains, but dose is still significantly reduced.
Heavy white towel	About 21%	Only about one-fifth of the dose gets through.
Black Lycra bike shorts	About 4%	Strongly blocks light despite being “athletic” wear.
Thick black neoprene knee sleeve	Essentially 0%	Almost complete blockage of light.

When those same fabrics were placed directly against the LEDs, the dose dropped even further. The lesson is that dark, dense, and rubbery materials like neoprene can essentially cancel your treatment over the covered area. Even seemingly “light” pieces like standard bike shorts may leave you with just a few percent of the intended power at the skin.

Gembared has looked at sunlight and clothing in a different way, focusing on how common garments transmit light from the sun over a broad range of wavelengths. Their analysis shows that many everyday shirts still allow a sizeable fraction of near-infrared from sunlight to reach the skin, often in the range of roughly 40 to 60 percent for NIR, even while they block most visible light. Pants, especially jeans, tight leggings, and dark sweatpants, tend to block almost all visible light and allow only small fractions of near-infrared through.

They also highlight key fabric principles:

Light-colored fabrics, especially white, let the most visible and near-infrared light through. Dark colors such as black and navy absorb most visible light but can still pass a notable amount of near-infrared, though visible red may be heavily suppressed. Cotton and polyester can transmit on the order of a third to more than half of incoming light across relevant wavelengths when untreated and loosely woven.

The bottom line from both the handheld-device experiment and textile studies is that you should treat clothing as a major variable in your dose. In a clinic trial, researchers control this by using direct skin exposure. For at-home wellness use, you cannot easily measure exactly how much dose is being lost, which is why most evidence-based guidance defaults to “as much bare skin as you comfortably can.”

Do You Need To Undress Completely?

There is no single correct answer, because it depends on your goals, environment, and comfort level. Evidence and expert commentary give a clear hierarchy of options.

Full-Body Sessions: When Nearly Nude Makes Sense

Full-body panels are designed to treat large areas at once. Research notes from Atria and several device brands describe protocols where people stand about 6 to 24 inches from a vertical panel for roughly 10 to 20 minutes per side, several days per week, to support general wellness, skin health, or musculoskeletal comfort.

Design and Health points out that for full-body sessions, maximizing exposed skin usually improves outcomes. Studies of targeted photobiomodulation in labs and clinics almost always treat bare skin, precisely because fabric makes dose unpredictable. If your goal is broad benefits such as systemic inflammation support, widespread joint or muscle relief, or full-body skin rejuvenation, exposing most of your skin is the most straightforward way to get a meaningful and consistent dose.

In my work with at-home users, people who are comfortable in a swimsuit or underwear for full-body sessions typically see smoother progress because they are not fighting against thick fabrics that block large areas. However, that does not mean you must be fully nude, especially if that would make you avoid sessions altogether.

Targeted Treatments: When Partial Clothing Is Enough

Many people use red light therapy for focused concerns such as facial skin, a single arthritic knee, or a sore low back. In those situations, Design and Health and Lifepro both note that everyday clothing is more acceptable as long as the actual treatment area is uncovered.

This might look like:

A T‑shirt lifted to expose the abdomen or low back while you keep pants on. Shorts or a robe that allow one knee or hip to be directly exposed. A comfortable bra while you treat neck, face, and upper chest.

You still get direct exposure on the key area, while staying mostly dressed. From a dose perspective, this is far better than leaving a target joint under neoprene, thick leggings, or jeans.

Pros And Cons Of Going Nude

Completely undressing has clear advantages. You remove fabric as a variable, you can rotate your body to expose different regions without thinking about waistbands or seams, and you make it easier for both red and near-infrared wavelengths to do their job. For people combining red light with full-body heat therapies, such as infrared saunas, sources like Body Lab Studios also highlight that minimal clothing helps sweat evaporate and reduces overheating risk.

The downsides are real, though. Not everyone has a private space that feels safe. Some people feel vulnerable undressing due to trauma history, body image, or cultural and religious values. Others simply find it too cold to be nude in a spare room where the panel lives.

From a wellness perspective, consistency matters more than perfection. Multiple sources, including Atria, Infraredi, and Fuel Health & Wellness, emphasize that three to five well-dosed sessions per week, sustained over weeks, are more important than one “ideal” nude session that you dread. If full nudity will make you skip treatments, a modest compromise with smart fabric choices is more therapeutic in the long run.

If You Keep Clothes On: How To Choose Smart Fabrics

When modesty, shared spaces, or temperature make clothing non-negotiable, you can still make thoughtful choices that reduce how much light you lose.

Best Clothing Choices For Red Light Sessions

Articles from Design and Health, Lifepro, BlockBlueLight, Kineon, and others consistently recommend similar options when clothing must be worn.

Light, breathable fabrics such as cotton or linen are preferred. Loosely woven, single-layer garments allow more light through than tight-knit, multi-layer outfits. Light colors like white, beige, and pastel shades interfere less with the light, whereas dark tones absorb more. A loose, light-colored T‑shirt is dramatically better than thick dark athleisure wear when it comes to light transmission.

Several sources also caution against shiny or metallic prints, sequins, foil logos, or reflective embellishments. These design elements can reflect or scatter light away from the skin instead of letting it pass through. Tight, compressive garments such as shapewear, compression leggings, or snug bike shorts not only block more light but can restrict blood flow, which undermines one of the therapy’s goals: improved microcirculation.

In practical terms, if you must stay somewhat clothed, treating in light cotton lounge shorts and a white tank top or T‑shirt is much closer to ideal than doing your session in dark yoga pants and a thick sweatshirt.

How Fabric And Color Affect Light In Practice

The detailed experiment from Light Therapy Insiders shows that even a simple thin black T‑shirt can cut your device’s effective power at the skin down to just a few percent of its original value, while a thick but light-colored shirt might leave you with just over half. Heavy towels, black lycra, and neoprene braces are particularly problematic, dropping the dose to somewhere between one-fifth and nearly zero.

Gembared’s examination of clothing and sunlight reinforces the pattern on a broader wavelength range. Light-colored, loosely woven shirts allow a meaningful amount of near-infrared from the sun to reach the skin, while darker and thicker garments drastically reduce both visible and near-infrared light. Pants fabrics, especially those that are dense and heavily dyed, block so much light that only small fractions of near-infrared get through.

They also point out a “hole effect”: the tiny spaces between threads in more porous fabrics act like miniature windows, allowing nearly full-intensity light through those gaps. That is one reason loose, thin garments behave better than tight, densely knit ones. Still, the resulting dose is patchy and less predictable than simply treating bare skin.

The practical takeaway is that if you are using clothes during red light therapy, you should expect a reduced dose and think of clothing as a compromise, not a free pass. When you cannot undress, choosing light, loose, single-layer garments in pale colors, and avoiding neoprene and compression wear over target areas, is the best way to preserve some of the therapy’s effectiveness.

Preparing Your Skin Before A Session

Clothing is not the only barrier between light and tissue. A surprising number of everyday products on your skin can also interfere with absorption.

Multiple sources, including Design and Health, Infraredi, Rouge, Red Light Rising, Leredd guidance, and BlockBlueLight, all advise using red light on clean, dry skin. Heavy makeup, mineral sunscreens, SPF foundations, thick moisturizers, and body oils can absorb or reflect some wavelengths, similar to a very thin “coating” of fabric. Red Light Rising specifically calls out sunscreen and SPF makeup as blockers not just of ultraviolet light but also of red and near-infrared.

A practical sequence many people find helpful is to schedule facial or upper-body sessions either first thing in the morning before applying products, or in the evening after cleansing. For body treatments, simple clean skin without thick lotions gives you the most predictable light penetration. Some practitioners do experiment with pairing certain topicals and red light to enhance absorption of active ingredients, but that is a more advanced strategy and not necessary to benefit from the therapy itself.

Hydration is another piece. Rouge and Red Light Rising both highlight emerging evidence that well-hydrated cells respond better to red light, because water-rich tissues can support energy production and repair more effectively. From a wellness standpoint, drinking water throughout the day and being reasonably hydrated before and after sessions is a low-risk way to support your body’s response.

Session Setup: Distance, Time, And Frequency With And Without Clothing

Once you have decided how much skin to expose and what to wear, the next layer is dose: how far you stand from the device, how long sessions last, and how often you repeat them.

Distance And Time On Bare Skin

Multiple sources, including Atria, Infraredi, Fuel Health & Wellness, The Curee, and BlockBlueLight, converge on similar practical ranges for at-home panels. They suggest placing the body somewhere around 6 to 12 inches from the panel for most uses, sometimes up to 24 inches for less intense exposure or larger coverage. Typical sessions last about 10 to 20 minutes per treatment area.

Fuel Health & Wellness summarizes expert recommendations that for muscle recovery and pain, about 10 to 20 minutes, three to five times per week over an initial period of roughly 12 to 16 sessions, is often used to gauge response. For cosmetic skin goals, some protocols are slightly more frequent at first, then taper to a maintenance rhythm a few times per week. The Curee and Jacuzzi’s wellness guide both emphasize that therapeutic effects are cumulative over days to weeks; more is not always better on any single day.

Cleveland Clinic echoes that meaningful improvements in skin or pain typically require repeated sessions over weeks or months, not one-off exposures. They also note that at-home devices are usually less powerful than clinic equipment, which means consistent use is key.

Dose Adjustments When Clothing Is Involved

Clothing complicates this picture. Light Therapy Insiders explicitly notes that when you must keep fabrics between the light and the skin, you may need to compensate with longer exposure or a higher-powered device to approach the dose you would get on bare skin. However, they also caution that each extra layer—fabric, skin, even bone—reduces intensity before it reaches deeper targets.

Because of the Goldilocks effect described by Atria, you should not simply double or triple your session time without reference to manufacturer guidelines. Overexposure can cause temporary skin irritation, tightness, or eye strain, and may paradoxically reduce benefit in some tissues. A safer strategy is to:

Use bare skin over the target area whenever you realistically can, even if other body parts remain clothed. Stay within the time and distance ranges your device manufacturer recommends. Monitor your own response in a simple journal: note comfort, skin changes, pain levels, and energy or sleep quality over several weeks.

If you notice minimal changes and you are consistently treating through fabric, that is a strong signal to increase skin exposure rather than continue to extend time with clothes on.

Safety, Medical Conditions, And Eye Protection

High-quality overviews from Cleveland Clinic, Brown Health, Atria, and others agree that red light therapy, when used as directed, is generally considered safe, noninvasive, and non-ionizing. It does not involve ultraviolet radiation and does not carry the same skin cancer risk as tanning or unprotected sun exposure.

That said, several cautionary notes are important.

Cleveland Clinic and Brown Health both emphasize that evidence is still developing and that red light therapy should not replace proven medical treatments for conditions such as skin cancer, severe arthritis, or autoimmune disease. It is best thought of as a complementary option.

Peak Performance Float and other wellness sources stress particular care for people taking photosensitizing medications. Drugs such as certain antibiotics, heart medications, and topical retinoids can make skin and eyes more sensitive to light. For these individuals, consulting a healthcare provider before starting red light therapy is essential. The same is true for those who are pregnant, have active cancer, have very sensitive or inflamed skin, or are considering large-area exposure in children.

Eye protection deserves special attention. Atria notes that panels are not lasers and use non-ionizing light, but multiple sources, including Design and Health, Infraredi, Lifepro, BlockBlueLight, and Peak Float, recommend protective eyewear when your face is close to a strong panel. Even if the light is not damaging, red and near-infrared brightness can be uncomfortable and may lead to strain. Many reputable devices include goggles and advise users to either wear them or keep eyes closed and slightly turned away during facial sessions.

How I Help Clients Decide What To Wear

When I coach people through setting up at-home red light therapy, we walk through a simple thought process together.

The first question is which area of the body is the priority. If someone is primarily targeting facial skin or a specific joint, we focus on exposing that region directly, even if the rest of the body remains dressed. A T‑shirt lifted above the treatment zone or shorts chosen specifically to leave a knee uncovered can transform results compared with treating through thick fabric.

The second question is where and when sessions will happen. A private bedroom or bathroom allows more flexibility than a shared living room. Some people create small routines: closing blinds, locking the door, using a robe that is easy to open in front of the panel, or keeping a designated lightweight “therapy outfit” nearby so the process feels simple and safe.

The third question is comfort and emotional readiness. For someone with a trauma history or strong modesty values, demanding full nudity would turn red light therapy into another source of stress. In those cases, we often start with targeted areas and partial clothing, using breathable, pale fabrics, then reassess after a few weeks. If they begin to feel more comfortable and see benefits, some naturally choose to uncover more skin at their own pace.

Across all of these scenarios, the core principles remain the same and are well supported by the research: clean bare skin over the treatment area, a sensible distance from the device, session times within recommended ranges, and a schedule you can sustain three to five times per week. Clothing is not inherently “wrong,” but it should be a conscious, informed choice rather than an afterthought.

Short FAQ: Clothing And Red Light Therapy

Question: Can red light therapy work at all through clothing? Answer: Several sources, including Lifepro, BlockBlueLight, Kineon, and Light Therapy Insiders, indicate that some red and near-infrared light can penetrate certain fabrics, particularly thin, light-colored cotton or linen. However, the dose is reduced, sometimes dramatically. For reliable, evidence-aligned results, you should treat the target area on bare skin whenever possible.

Question: Is it ever okay to keep underwear or a swimsuit on? Answer: For full-body wellness sessions, many people comfortably wear underwear or a swimsuit while ensuring that key treatment areas are uncovered. Design and Health notes that for targeted treatments, clothing is more acceptable as long as the specific body region being treated is exposed directly. Underwear or swimwear is usually a reasonable compromise when modesty is a priority, provided it is not made of thick, dark, or neoprene-like material over target zones.

Question: What if I am self-conscious about my body or in a shared home? Answer: Emotional safety is as important as physical dosing. If fully undressing feels uncomfortable, start with partial exposure. Focus on uncovering the main treatment area and wear light, loose, pale clothing elsewhere. Build a simple privacy routine and reassess over time. Consistent, “good enough” sessions that respect your boundaries will serve you better than an “ideal” protocol you avoid.

Red light therapy works best when light truly meets skin. The more you understand how fabric, color, and fit shape the dose your cells receive, the easier it becomes to design sessions that honor both your physiology and your privacy. If you keep the treatment area on clean bare skin, choose breathable light fabrics where clothing stays on, and follow evidence-based timing and safety guidance, you can confidently integrate red light into your wellness routine in a way that feels both effective and deeply respectful of your body.