Oil for
the hinges.
Osteoarthritis affects the whole joint: cartilage, the bone beneath it, the lining around it, and the muscles that move it.
Stiffness and pain make the movement your joints need feel like the last thing you want to do. Here's what the research shows about far-infrared warmth, and where it fits in your plan.
Knee pain score after 4 weeks with a far-infrared plaster, vs. 79 → 73 with placebo.1
Treated knees showing fluid buildup on ultrasound, before vs. after far infrared.1
Conditionally recommended for OA comfort in the American College of Rheumatology guideline.2
Gentle warmth helped cartilage-cell activity; intense heat did the opposite. This does not set a sauna dose.3
A whole-joint condition.
For years, osteoarthritis was described as cartilage simply wearing away. Researchers now know several parts of the joint change together.
The cushion thins.
Cartilage thins and loses its cushion.
The structure changes.
The bone beneath the cartilage remodels abnormally.
Inflammation develops.
The joint lining becomes mildly inflamed and can produce extra fluid.
Less use adds stiffness.
Muscles and tendons stiffen and weaken with less use.
Exercise stays at the center. The most effective plans address the whole joint. Warmth can help make movement easier.
A far-infrared plaster for knee osteoarthritis.
Bagnato et al. · 60 patients · Randomized, placebo-controlled · 4 weeks
Italian researchers recruited people whose knee pain persisted despite acetaminophen or anti-inflammatory medication. Half wore a plaster coated with far-infrared-emitting minerals behind the knee for 12 hours a day. The other half wore an identical plaster without the minerals.
The researchers measuring the results did not know which plaster each person wore.
No side effects were reported.1 It was a small, short study and needs to be repeated with larger groups, but it is the clearest direct test of far infrared in osteoarthritis so far.
The delivery method matters. This study used a wearable mineral emitter that re-radiates body heat at one joint for many hours. That's much closer to how Raylieve works than to a sauna session. Raylieve itself has not been tested in this trial.
Other studies using different infrared wavelengths, including near-infrared and lasers, did not find a benefit in osteoarthritis.4 The type of infrared matters.
Whole-body warmth. Targeted comfort.
Relax Sauna
Whole-body warmth before movement, for people considering comfort across several stiff joints.
- For a whole-body warming routine
- Can fit before walking, stretching, or exercise
- Circulation research explores nitric oxide and NRF2 pathways.5,6
Evidence: immediate relief of pain and stiffness after infrared sauna has been reported in other arthritis types. No sauna trial in osteoarthritis has been identified here.7
Raylieve
A mineral matrix that returns your body heat as far infrared for localized exposure.
- For people considering a localized option
- Use according to product instructions
- Similar mineral-emitter principle to the lead study
Evidence: the lead study tested a similar mineral-emitter approach. Raylieve itself hasn't been tested in a trial yet.
What researchers are exploring.
Tissue flexibility
Warmth makes collagen in tendons and joint capsules more flexible, especially when paired with gentle stretching. Looser joints can make exercise more comfortable.
Laboratory research on tissue warming and extensibility.8
Inflammatory activity
Far infrared calmed inflammatory gene activity in an arthritis model, and fluid buildup dropped in the lead study.
Animal research plus one human trial.9,1
Bone remodeling
In a 2026 rat study of osteoarthritis, daily far infrared eased pain and slowed the cells that break down bone under the cartilage.
Animal research only; not yet tested in people.10
Response to warmth
In the lab, warmth up to 41°C helped cartilage cells stay healthy and active, while intense heat harmed them.
Cell research only. This is not a recommended sauna setting or body temperature.3
Promising findings. Defined limits.
Movement comes first.
Exercise is the foundation of OA care, and heat therapy is a guideline-supported option for comfort.
One plaster trial.
A randomized trial of a far-infrared plaster reduced knee pain and fluid buildup.
Results vary.
Other types of infrared did not help, and ordinary hot packs showed limited benefit.
Sauna-specific outcomes.
No study reviewed here tested far-infrared sauna in osteoarthritis or showed cartilage changes in people.
What we do not claim.
- Far infrared does not regrow cartilage or reverse joint damage in people.
- It has not been shown to delay or prevent joint replacement.
- It does not replace exercise, weight management, physical therapy, or your doctor's treatment plan.
- Animal and lab findings are promising clues that still need testing in people.
- A joint that suddenly becomes hot, red, and swollen needs medical attention before heat therapy.
What would settle it?
A larger trial comparing far infrared with a sham device, combined with a standard exercise program, measuring pain and function over 12 weeks, walking and chair-stand tests, joint inflammation on imaging, and whether people stick with their exercise.
That's the kind of question our research initiative is designed to pursue.
Make comfort part of the plan.
No osteoarthritis-specific sauna dose has been established. Discuss session duration, frequency, and product use with your clinician, particularly if you have other medical conditions.
Warm up before you move.
If your clinician agrees, comfortable warmth before walking, stretching, or exercise may help make movement easier.
Build steady habits.
Keep exercise and your prescribed care at the center of your routine. Osteoarthritis management depends on consistency.
Follow product guidance.
If you choose Raylieve, follow the product instructions and your clinician's guidance. The plaster study does not establish a treatment schedule or benefit for Raylieve itself.
Keep warmth comfortable.
Stop if you feel overheated, dizzy, unwell, or notice skin irritation.
Pause for new swelling.
A joint that suddenly becomes hot, red, or very swollen needs medical assessment before further heat use.
Track what changes.
Over four to six weeks, note pain, morning stiffness, walking comfort, and pain-reliever use. Discuss changes with your clinician.
Talk to your clinician first if you have:
- A joint that is suddenly hot, red, or very swollen, or pain with fever
- Locking, catching, or giving way of the joint, or rapidly worsening pain
- Heart disease, uncontrolled blood pressure, or a recent cardiac event
- Reduced feeling in the skin, such as from diabetic neuropathy, or broken skin over the joint
- A recent joint replacement or injection, or are pregnant
Make room for easier movement.
The Relax Sauna delivers 9.4 µm far infrared with your head outside the cabin, offering whole-body warmth at home.
Consider where comfortable warmth fits alongside the movement and medical care your joints need.
References
- Bagnato GL, et al. Far infrared emitting plaster in knee osteoarthritis: a single blinded, randomised clinical trial. Reumatismo. 2012;64(6):388-394.
- Kolasinski SL, et al. 2019 ACR/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis Care Res. 2020;72(2):149-162.
- Hojo T, et al. Effect of heat stimulation on viability and proteoglycan metabolism of cultured chondrocytes. J Orthop Sci. 2003;8:396-399.
- Tsagkaris C, et al. Infrared radiation in the management of musculoskeletal conditions and chronic pain: a systematic review. Eur J Investig Health Psychol Educ. 2022;12(3):334-343.
- Park JH, et al. Far-infrared radiation acutely increases nitric oxide production. Biochem Biophys Res Commun. 2013;436(4):601-606.
- Bagabir H, et al. Far infrared therapy improves vascular function via cytoprotective pathways. Free Radic Biol Med. 2025;241:438-446.
- Oosterveld FGJ, et al. Infrared sauna in patients with rheumatoid arthritis and ankylosing spondylitis. Clin Rheumatol. 2009;28(1):29-34.
- Lehmann JF, et al. Effect of therapeutic temperatures on tendon extensibility. Arch Phys Med Rehabil. 1970;51(8):481-487.
- Chen et al. Far infrared irradiation suppresses experimental arthritis in rats. J Adv Res. 2022;38:107-118.
- Qin B, et al. Alleviation of osteoarthritis progression through far-infrared therapy. Pharmacol Res. 2026;228:108221.
