Both red light therapy and infrared saunas use light on the infrared spectrum. Both claim health benefits. But they work through fundamentally different mechanisms, and understanding that difference matters if you are trying to decide which approach is right for you.
In this article
The core difference
The simplest way to understand the distinction: red light therapy delivers light energy to your cells. Infrared saunas deliver heat to your body.
They happen to use overlapping regions of the electromagnetic spectrum, but the intent and mechanism are entirely different. A sauna heats your body to make you sweat. A red light therapy device delivers specific wavelengths to support cellular energy production without any meaningful temperature increase.
This distinction matters because the published research behind each approach examines very different biological processes and outcomes.
How red light therapy works
Red light therapy, formally called photobiomodulation, uses wavelengths in the 620-940nm range to deliver light energy to the mitochondria inside your cells. The key chromophore is cytochrome c oxidase, an enzyme that absorbs light at specific wavelengths (particularly around 660nm and 850nm) and may use that energy to support ATP production (Hamblin, 2017).
The mechanism is photochemical, not thermal. A properly designed red light therapy device does not heat your tissue to any meaningful degree. The therapeutic effect comes from the interaction between photons and cellular enzymes, not from temperature.
Published research on photobiomodulation has examined outcomes including joint discomfort (Bjordal et al., The Lancet, 2009), back discomfort (Huang et al., Systematic Reviews, 2015), hair growth (Lanzafame et al., Lasers in Surgery and Medicine, 2014), and muscle recovery (Ferraresi et al., Lasers in Medical Science, 2014).
How infrared saunas work
Infrared saunas use far-infrared wavelengths (typically 3,000nm to 100,000nm) to heat your body directly, raising your core temperature and inducing sweat. This is a thermal mechanism. The sauna heats you from the inside out rather than heating the surrounding air like a traditional sauna.
The proposed benefits of infrared saunas are primarily related to the physiological effects of heat exposure: increased heart rate, increased circulation, sweating and associated detoxification claims, and relaxation. Some research has examined cardiovascular effects of regular sauna use.
It is worth noting that far-infrared wavelengths (3,000nm+) used in saunas are completely different from the near-infrared wavelengths (810-940nm) used in photobiomodulation. They interact with tissue through different mechanisms and at different depths.
Side-by-side comparison
Red light therapy
Infrared sauna
Mechanism
Photochemical (light to cellular energy)
Thermal (heat to raise body temperature)
Wavelengths
620-940nm (red and near-infrared)
3,000-100,000nm (far-infrared)
Session time
10 to 15 minutes
20 to 45 minutes
Body response
No significant temperature change
Elevated core temperature, sweating
Targeting
Specific body area (wrap, cap, panel)
Whole body
Location
Any room, no installation
Dedicated space or facility
Cost
$100 to $500 for home devices
$1,000 to $8,000+ for home units, or $30 to $60 per studio session
Published RCTs
5,000+ studies on photobiomodulation
Smaller evidence base, fewer RCTs
What does the research say?
Red light therapy research
Over 5,000 published studies on photobiomodulation across peer-reviewed journals.
Multiple meta-analyses and systematic reviews for specific conditions (joint discomfort, back discomfort, hair growth, muscle recovery).
Published in high-impact journals including The Lancet, Lasers in Surgery and Medicine, and the Journal of Biomedical Optics.
Well-defined mechanism of action through cytochrome c oxidase and mitochondrial ATP production.
Infrared sauna research
A growing but smaller body of published research, primarily focused on cardiovascular and relaxation outcomes.
Some observational studies from Finland on regular sauna use and cardiovascular health, though these included traditional saunas, not specifically infrared.
Fewer condition-specific RCTs compared to photobiomodulation.
The mechanism is primarily thermal, meaning the benefits are related to heat exposure rather than a specific photochemical interaction.
Both modalities have published research supporting their use. However, the evidence base for photobiomodulation is significantly larger and includes more condition-specific randomized controlled trials. The mechanisms are fundamentally different, which means they are not interchangeable for specific applications.
Can you use both?
Yes. They address different things through different mechanisms, so they are not in conflict. Some people use an infrared sauna for general relaxation and cardiovascular conditioning, and red light therapy for targeted musculoskeletal or hair applications.
If you are choosing one or the other based on budget or practicality, the decision comes down to what you are trying to accomplish:
If your primary goal is targeted relief for a specific area (back, knee, hair), red light therapy has a stronger evidence base for those applications and is more practical for daily home use.
If your primary goal is general relaxation and heat exposure, an infrared sauna provides a full-body experience that many people find enjoyable and relaxing.
Which is right for you?
Choose red light therapy if
You want to target a specific body area (back, joints, hair, muscles).
You want short, daily sessions (10 to 15 minutes).
You want a portable device you can use anywhere.
Published research on your specific concern matters to you.
Budget is a consideration ($100 to $500 vs $1,000+).
Choose an infrared sauna if
You want a full-body heat experience.
Relaxation and stress reduction are your primary goals.
You have the space and budget for a home unit, or access to a studio.
You enjoy the ritual of a longer session (20 to 45 minutes).
Sweating and the associated feeling of "cleansing" is important to you.
The bottom line
Red light therapy and infrared saunas are not the same thing, despite both using light on the infrared spectrum. Red light therapy works through a photochemical mechanism, delivering light energy to mitochondria to support cellular function. Infrared saunas work through a thermal mechanism, heating your body to induce sweat and circulation.
For targeted applications like back discomfort, joint discomfort, hair growth, and muscle recovery, the published evidence base for photobiomodulation is substantially larger and more specific. For general relaxation and heat exposure, saunas have their own appeal.
They are not interchangeable, but they are not mutually exclusive either. Understanding the difference helps you make an informed choice based on what you are actually trying to achieve.
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Sources
Bjordal et al., The Lancet, 2009
Ferraresi et al., Lasers in Medical Science, 2014
Hamblin, Mechanisms and applications of the anti-inflammatory effects of photobiomodulation, 2017
Huang et al., Journal of Biomedical Optics, 2018
Huang et al., Systematic Reviews, 2015
Lanzafame et al., Lasers in Surgery and Medicine, 2014
Individual results may vary. The information in this article is for educational purposes only and is not intended as medical advice. Clinical research cited relates to the general modality of photobiomodulation, not to any specific product. Consult your healthcare provider before starting any new wellness routine.