Red light therapy is having a moment. It’s on the shelves of medical spas, in professional wellness studios, on TikTok, and inside handheld masks people wave over their faces at night. But underneath the glowing panels and the marketing, there’s an actual, well-characterized field of science – one that researchers have been studying for more than fifty years.
Red light therapy is the use of specific wavelengths of red and near-infrared light to stimulate the energy-producing machinery inside your cells. Its formal scientific name is photobiomodulation (PBM), and unlike many wellness trends, it isn’t magic or mysticism. It’s photochemistry: light of a precise wavelength being absorbed by a specific molecule inside your cells, triggering a measurable biological response.
This guide breaks down what red light therapy actually is, how it works at the cellular level, why wavelength matters so much, and how to tell a serious device from an underpowered one.
What Is Red Light Therapy?
Red light therapy delivers concentrated, low-energy light – most commonly red light at 635 nanometers and near-infrared light at 850 nanometers – onto the skin and tissue. It sits in a completely different part of the light spectrum from ultraviolet (UV), the wavelength used in tanning, and from the focused beam of a surgical laser. Red and near-infrared light are simply absorbed by your cells and put to work.
You may also hear it called by several other names, which all describe the same underlying process:
- Photobiomodulation (PBM) – the current, scientifically preferred term
- Low-level laser therapy (LLLT) – an older term from when lasers were the main light source
- Cold laser therapy – because it produces no meaningful heat
- LED light therapy – when the light source is an LED array rather than a laser
The core idea is the same across all of them: certain wavelengths of light can penetrate the skin, get absorbed by a specific target inside your cells, and nudge those cells toward more efficient energy production. From there, a cascade of downstream effects follows.
The Science: How Photobiomodulation Works at the Cellular Level
To understand red light therapy, you have to zoom all the way in – to the tiny structures inside your cells called mitochondria.
Your mitochondria and the “light switch” enzyme
Mitochondria are often called the powerhouses of the cell, and for good reason. They produce the vast majority of your cellular energy in the form of a molecule called ATP (adenosine triphosphate). Think of ATP as the fuel that powers nearly everything your cells do – repairing tissue, building proteins, fighting inflammation, and staying alive.
Sitting inside your mitochondria is an enzyme with an intimidating name: cytochrome c oxidase, often shortened to CCO. It’s the fourth and final complex in the electron transport chain, the assembly line that produces ATP. And here’s the crucial part: CCO is widely considered the primary molecule in your body that absorbs red and near-infrared light. Scientists call this kind of light-absorbing molecule a chromophore.
CCO contains metal centers – two iron-based heme sites and two copper sites – and these metal centers are what researchers believe red and near-infrared photons interact with. This is why specific wavelengths matter so much, a point we’ll return to shortly. Much of this leading model was established through decades of pioneering spectroscopy work by researcher Dr. Tiina Karu, who mapped how light wavelengths line up with CCO’s absorption profile.
The nitric oxide “handbrake”
Here’s where it gets interesting. When your cells are stressed, inflamed, aging, or low on oxygen, a molecule called nitric oxide (NO) can build up and bind to cytochrome c oxidase. When NO parks itself on CCO, it acts like a handbrake – it can slow the enzyme’s work, and with it, ATP production, right when your cells may need energy the most.
The leading hypothesis is that red and near-infrared light help release that handbrake. When photons of the right wavelength are absorbed by CCO, they appear to photodissociate the nitric oxide – essentially knocking it loose from the enzyme. With the handbrake off, the electron transport chain can speed back up, oxygen consumption increases, and ATP production ramps up. Stressed or underperforming cells get an energy boost. (Researchers are still refining the details of this mechanism, but it’s the most widely supported explanation.)
The downstream cascade
Increased ATP is the headline effect, but it’s really just the first domino. Once photobiomodulation gets going, a cascade of secondary and tertiary effects is thought to follow:
- A brief, controlled burst of reactive oxygen species (ROS). In small amounts, ROS act as signaling molecules that tell the cell to adapt and strengthen its own defenses. (This is one reason more light isn’t better – a point we’ll cover below.)
- Release of nitric oxide into surrounding tissue, which helps widen blood vessels and improve local circulation, bringing more oxygen and nutrients to the area.
- Modulation of calcium signaling, another important cellular messenger.
These secondary signals then activate a range of transcription factors – the switches that turn genes on and off. The proposed end result is improved cell survival, increased cell proliferation and migration, reduced inflammation, and new protein synthesis (including proteins like collagen). In other words: the light doesn’t do the healing itself. It’s thought to give your cells more energy and better signaling so they can do what they’re already built to do, more effectively.
Why Wavelength Matters So Much
Not all red light is created equal, and this is where a lot of consumer products fall short. Because cytochrome c oxidase absorbs light most efficiently at specific wavelengths, the light has to match the enzyme’s absorption peaks to produce a strong biological response. The two most researched and effective ranges are:
- Red light (~630–660 nm, with 635 nm heavily studied): This wavelength is absorbed well but penetrates relatively shallowly, making it ideal for the skin – targeting the epidermis and upper dermis where collagen-producing cells live.
- Near-infrared light (~810–850 nm): This wavelength is invisible to the human eye and penetrates much deeper, reaching muscle, joints, and deeper tissue. It’s the range favored for recovery and deep-tissue applications.
The absorption peaks aren’t a marketing decision – they’re determined by the physics of the metal centers inside CCO. A device emitting the wrong wavelength, or spreading its power too thinly across many “bonus” wavelengths, may deliver far less benefit than its output specs suggest. This is why quality equipment is built around specific, proven wavelengths: EverSun’s professional red light bed, for example, is engineered around 635 nm red and 850 nm near-infrared – the two bands with the strongest research behind them.
Red Light vs. Near-Infrared Light: What’s the Difference?
People often use “red light therapy” as an umbrella term, but red and near-infrared light do slightly different jobs:
| Red light (~635 nm) | Near-infrared (~850 nm) | |
| Visible? | Yes (that signature red glow) | No (invisible to the eye) |
| Penetration depth | Shallower – skin surface and upper layers | Deeper – muscle, joints, deeper tissue |
| Best suited for | Skin tone, texture, collagen, surface healing | Muscle recovery, deep tissue, circulation |
The strongest systems combine both, giving you surface and deep coverage in a single session. A device that only offers one is optimized for a narrower job.
The Biphasic Dose Response: Why More Isn’t Better
This is one of the most important – and most misunderstood – principles in photobiomodulation. Red light therapy follows what scientists call a biphasic dose response (also known as a hormetic or “U-shaped” response).
In plain terms: there’s a sweet spot. Too little light produces no meaningful effect. The right dose stimulates your cells. But too much light doesn’t produce more benefit – it can actually start to reduce or reverse the effect, and at very high levels may even become inhibitory.
This is why session length and device power matter, and why “just leave it on longer” is the wrong instinct. It’s also a big reason professional-grade equipment – where the intensity delivered to the tissue is high and consistent – tends to produce more reliable results than guessing with an underpowered home gadget.
Is Red Light Therapy the Same as a Tanning Bed or Infrared Sauna?
No – and the differences matter:
- Tanning beds emit ultraviolet (UV) light, a different part of the spectrum – it’s what stimulates the skin’s melanin to produce a tan. Red light therapy uses no UV at all, so it works through an entirely different mechanism and doesn’t tan the skin. (A “hybrid” bed is its own category – it pairs UV tanning lamps with red light in one unit.)
- Infrared saunas primarily use far-infrared radiation to generate heat and raise body temperature. Red light therapy uses red and near-infrared light to drive a photochemical reaction in your cells – and produces essentially no heat. Different mechanism, different goal.
- Surgical or aesthetic lasers use intense, focused light to ablate or reshape tissue deliberately. Red light therapy uses low-energy light calibrated to stimulate, not to cut.
What Makes a Red Light Device Actually Work
If the science comes down to getting an effective dose of the right wavelength into your cells, then two practical factors decide whether a device delivers: output (how much light energy it produces) and proximity (how close that light is to your body). A weak panel held far from the skin delivers a fraction of the dose it appears to.
This is the design principle behind EverSun’s professional red light bed. It packs roughly 28,000 LEDs – more than 22,000 red at 635 nm and over 5,000 near-infrared at 850 nm – in a high-intensity configuration, and uses zero-gravity positioning to bring your whole body as close to the light as possible for maximum exposure. It’s an FDA-registered, medical-grade device that emits no UV, and sessions run about 15 minutes. That combination of proven wavelengths, high LED density, and close proximity is exactly what the science points to for real results – and it’s difficult to replicate with a small at-home panel.
Is Red Light Therapy Safe?
Compared to many treatments, red light therapy has a notably high safety margin. It’s non-invasive, drug-free, uses no UV, and generates virtually no heat. Dermatologists generally describe the risk profile as low. That said, “safe” doesn’t mean “no precautions”:
- Protect your eyes. Prolonged direct exposure of the eyes to intense light can be uncomfortable, so eye protection is available during sessions.
- Watch for photosensitivity. Certain medications and conditions increase light sensitivity. If you take photosensitizing drugs or have a condition like melasma, check with a professional first.
- Mild, temporary side effects can include slight redness or warmth – usually minor and short-lived.
It’s also worth understanding regulatory language, because it gets used loosely in marketing. FDA-registered means a device and its manufacturer are listed with the FDA. FDA-cleared means a device is considered substantially equivalent to an existing legally marketed product for a specific use. FDA-approved is a higher bar reserved for products that go through the FDA’s most rigorous premarket review. These are not interchangeable, so it’s worth knowing which one a given claim actually refers to.
Red Light at EverSun
Red and near-infrared light show up across several EverSun services, each suited to a different goal:
- Our red light bed – full-body 635 nm red and 850 nm near-infrared for skin, circulation, and recovery.
- LightStim Pro Panel facials – targeted facial treatments; the Anti-Aging panel is FDA-cleared for wrinkles, fine lines, and signs of aging, and the Clearing panel is FDA-cleared for mild-to-moderate acne.
- Our red light and vibration platform – red light paired with a whole-body vibration plate in a 12-minute session.
- Our infrared salt therapy booth – combines infrared light with dry salt therapy.
- Our hybrid sunbed – pairs UV tanning with red light in a single unit.
If you’re new to red light and not sure where to start, our team can walk you through which service fits your goals. Please note, services vary by club location.
Frequently Asked Questions
How long does it take to see results from red light therapy? It varies by goal. Circulation and short-term effects can be quick, but structural changes like collagen remodeling build over weeks of consistent sessions. Most protocols involve several sessions per week over one to three months.
Does red light therapy have UV in it? No. A dedicated red light device uses red and near-infrared wavelengths and contains no ultraviolet light, so it works differently from a tanning bed and doesn’t tan the skin. (Hybrid beds that combine UV and red light are the exception, and they’re labeled as such.)
Can you do red light therapy every day? For many applications, frequent sessions are fine, but because of the biphasic dose response, more is not automatically better. Following a structured protocol – the right dose at the right frequency – matters more than maximizing exposure.
Is professional red light therapy better than an at-home device? Often, yes – mainly because professional systems deliver higher output across effective wavelengths and position the light close to the body, so you actually receive a therapeutic dose. Many inexpensive home devices are underpowered, meaning longer sessions for weaker results.
Does red light therapy actually work, or is it a fad? The underlying mechanism – photons absorbed by cytochrome c oxidase boosting cellular energy – is well-supported and has been studied for decades. What’s overhyped is the breadth of claims. The core science is real; the miracle-cure marketing is not.
The Bottom Line
Red light therapy isn’t a gimmick – it’s a genuine biological process. Specific wavelengths of red (635 nm) and near-infrared (850 nm) light are absorbed by cytochrome c oxidase inside your mitochondria, helping release the nitric oxide “handbrake,” supporting ATP production, and setting off a cascade of regenerative signals. The keys to real results are the right wavelength, an effective dose, and consistency over time – which is exactly what a properly built professional device is designed to deliver.
Curious what a session feels like? EverSun’s red light bed and LightStim photo facial treatments make professional-grade red light easy to try – reach out and we’ll help you find the right fit.
Sources
- Karu T. Primary and secondary mechanisms of action of visible to near-IR radiation on cells. Journal of Photochemistry and Photobiology B: Biology. 1999;49(1):1–17.
- Hamblin MR. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics. 2017;4(3):337–361.
- Hamblin MR. Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation. Photochemistry and Photobiology. 2018;94(2):199–212.
- Wunsch A, Matuschka K. A controlled trial to determine the efficacy of red and near-infrared light treatment in patient satisfaction, reduction of fine lines, wrinkles, skin roughness, and intradermal collagen density increase. Photomedicine and Laser Surgery. 2014;32(2):93–100.
- Cleveland Clinic. Red Light Therapy.
This article is for educational purposes only. It is not intended to diagnose, treat, cure, or prevent any disease, and it is not a substitute for advice from a qualified healthcare professional. While many studies support the benefits of light-based and skincare treatments, results vary from person to person. LightStim Photofacial (Anti-Aging) devices are FDA-cleared to treat wrinkles, fine lines, and signs of aging, and LightStim Blue (Clearing) is FDA-cleared to treat mild-to-moderate acne. Consult your healthcare provider about any potential interactions before beginning a new treatment.