Biostimulation Therapy; Indications, Contraindications

Biostimulation Therapy/Infrared Radiation Therapy (IR) sometimes called infrared light is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye, although IR at wavelengths up to 1050 nanometers (nm)s from especially pulsed lasers can be seen by humans under certain conditions.[rx][rx] IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers (frequency 430 THz), to 1 millimeter (300 GHz).[rx] Most of the thermal radiation emitted by objects near room temperature is infrared. As with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon.

Infrared (IR) radiation is electromagnetic radiation with wavelengths between 760 nm and 100,000 nm. Low-level light therapy (LLLT) or photobiomodulation (PBM) therapy generally employs light at red and near-infrared wavelengths (600–100 nm) to modulate biological activity. Many factors, conditions, and parameters influence the therapeutic effects of IR, including fluency, irradiance, treatment timing and repetition, pulsing, and wavelength. Increasing evidence suggests that IR can carry out photostimulation and photobiomodulation effects particularly benefiting neural stimulation, wound healing, and cancer treatment. Nerve cells respond particularly well to IR, which has been proposed for a range of neurostimulation and neuromodulation applications, and recent progress in neural stimulation and regeneration are discussed in this review.

Another Name

You may have heard of red light therapy (RLT) by its other names, which include:

Biostimulation Therapy

Types of Low-Power Laser Therapy/LPLT

IR is divided into different bands: Near-Infrared (NIR, 0.78~3.0 μm), Mid-Infrared (MIR, 3.0~50.0 μm) and Far-Infrared (FIR, 50.0~1000.0 μm) as defined in standard ISO 20473:2007 Optics and photonics — Spectral bands []

Infrared light immediately follows red light on the electromagnetic spectrum.  Infrared (IR) light energy is broken down into three groups:

  • Near Infrared – also called infrared-A (IR-A).  Near IR spans wavelengths 760 to 1,400 nm.  Most home therapy devices use these wavelengths.
  • Mid Infrared – also called infrared B (IR-B) – These wavelengths are used in many household electronic devices such as remote controls.
  • Far Infrared –  or IR-C– also known as longwave infrared, thermal infrared (thermal-IR).  This is the largest part of the IR spectrum, used in infrared saunas.

Most studies showing benefits of red/NIR light therapy used light outputs of 20-200mW/cm2. This is basically a measurement of power density – how much power the light is emitting (in watts) over how big of an area. To put that in different terms, if you shine the light on your torso (let’s say, for the sake of ease of calculation, that it’s an area of 50cm x 40cm, which equals 2,000cm2). And the light you’re using is 200 watts (which is 200,000mW), then you have 200,000mW/2,000cm2 = 100mW/cm2

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Commonly used sub-division scheme

A commonly used sub-division scheme is:[rx]

Division name Abbreviation Wavelength Frequency Photon energy Temperature[rx] Characteristics
Near-infrared NIR, IR-A DIN 0.75–1.4 µm 214–400 THz 886–1653 meV 3,864–2,070 K
(3,591–1,797 °C)
Defined by water absorption, and commonly used in fiber optic telecommunication because of low attenuation losses in the SiO2 glass (silica) medium. Image intensifiers are sensitive to this area of the spectrum; examples include night vision devices such as night vision goggles. Near-infrared spectroscopy is another common application.
Short-wavelength infrared SWIR, IR-B DIN 1.4–3 µm 100–214 THz 413–886 meV 2,070–966 K
(1,797–693 °C)
Water absorption increases significantly at 1450 nm. The 1530 to 1560 nm range is the dominant spectral region for long-distance telecommunications.
Mid-wavelength infrared MWIR, IR-C DIN; MidIR.[rx] Also called intermediate infrared (IIR) 3–8 µm 37–100 THz 155–413 meV 966–362 K
(693–89 °C)
In guided missile technology the 3–5 µm portion of this band is the atmospheric window in which the homing heads of passive IR ‘heat seeking’ missiles are designed to work, homing on to the Infrared signature of the target aircraft, typically the jet engine exhaust plume. This region is also known as thermal infrared.
Long-wavelength infrared LWIR, IR-C DIN 8–15 µm 20–37 THz 83–155 meV 362–193 K
(89 – −80 °C)
The “thermal imaging” region, in which sensors can obtain a completely passive image of objects only slightly higher in temperature than room temperature – for example, the human body – based on thermal emissions only and requiring no illumination such as the sun, moon, or infrared illuminator. This region is also called the “thermal infrared”.
Far infrared FIR 15–1000 µm 0.3–20 THz 1.2–83 meV 193–3 K
(−80.15 – −270.15 °C)
(see also far-infrared laser and far infrared)
NIR and SWIR are sometimes called “reflected infrared”, whereas MWIR and LWIR is sometimes referred to as “thermal infrared”. Due to the nature of the blackbody radiation curves, typical “hot” objects, such as exhaust pipes, often appear brighter in the MW compared to the same object viewed in the LW.

A third scheme divides up the band based on the response of various detectors:[rx]

  • Near-infrared – from 0.7 to 1.0 µm (from the approximate end of the response of the human eye to that of silicon).
  • Short-wave infrared – 1.0 to 3 µm (from the cut-off of silicon to that of the MWIR atmospheric window). InGaAs covers to about 1.8 µm; the less sensitive lead salts cover this region.
  • Mid-wave infrared – 3 to 5 µm (defined by the atmospheric window and covered by indium antimonide [InSb] and mercury cadmium telluride [HgCdTe] and partially by lead selenide [PbSe]).
  • Long-wave infrared – 8 to 12, or 7 to 14 µm (this is the atmospheric window covered by HgCdTe and microbolometers).
  • Very-long wave infrared (VLWIR) – (12 to about 30 µm, covered by doped silicon).

Indications of Low-Power Laser Therapy/LPLT

Additional clinical research is needed to prove that RLT is effective. At the moment, however, there’s some evidence to suggest that RLT may have the following benefits:

  • Promotes wound healing and tissue repair
  • Improves hair growth in people with androgenic alopecia
  • Help for the short-term treatment of carpal tunnel syndrome
  • Stimulates healing of slow-healing wounds, like diabetic foot ulcers
  • Skin Wounds
  • Photo prevention
  • Relieve pain
  • Stiffness
  • Fatigue of rheumatoid arthritis
  • Ankylosing spondylitis
  • Potentiate photodynamic therapy
  • Treat ophthalmic, neurological, and psychiatric disorders, and
  • Stimulate the proliferation of mesenchymal and cardiac stem cells
  • Reduces psoriasis lesions
  • Aids with short-term relief of pain and morning stiffness in people with rheumatoid arthritis
  • reduces some of the side effects of cancer treatments, including oral mucositis
  • Improves skin complexion and builds collagen to diminish wrinkles
  • Helps to mend sun damage
  • Prevents recurring cold sores from herpes simplex virus infections
  • Improves the health of joints in people with degenerative osteoarthritis of the knee
  • Helps diminish scars
  • Relieves pain and inflammation in people with pain in the Achilles’ tendons
  • Reduce the signs of damage, DNA damage, [rx] and aging from UV rays[rx]
  • Reduce wrinkles[rx]
  • Reduce color patches, hyperpigmentation, and skin discoloration[rx]
  • Enhance collagen synthesis and collagen density (research has shown it can enhance production of collagen by 31%)[rx],[rx]
  • Accelerate repair in the epithelial layer of skin
  • Combat other skin conditions like acne, keloids, vitiligo, burns, herpes virus sores, and psoriasis
  • Speed wound healing by enhancing skin tissue repair and growth of skin cells
  • Chronic neck pain[rx]
  • Knee pain[rx]
  • Fibromyalgia
  • Low back pain
  • Chronic pain in the elbow, wrist, and fingers
  • Chronic joint disorders
  • Sacroiliac joint pain
  • Chronic tooth pain
  • Osteoarthritic pain
  • Tendinitis and myofascial pain[rx]
  • Benefit cognitive performance and memory
  • The improved mitochondrial function of brain cells
  • Have a protective effect on neurons
  • Improve cellular repair of neurons
  • Increase brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF)
  • Decrease brain inflammation (decreased pro-inflammatory cytokines and increased anti-inflammatory cytokines)

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Various medical applications of IR radiation for different cells and tissue tissues.

Medical Applications Author, reference Target The light source or material Wavelengths Results
Wound Healing Toyokawa et al. [] Skin wound in rat Ceramic-coated sheet 5.6 ~ 25 μm (maximal intensity of 8 ~ 12 μm) Promoted wound healing and expression of TGF-β1
Wound Healing Gupta et al. [] Dermal abrasions in mice Diode laser 810 nm Enhanced collagen accumulation and healing effects
Wound Healing Santana-Blank et al. [, ] Soft tissues in the rat Diode laser 904nm Promotes wound healing and exclusion zone (EZ) growth (1H-NMR 1/T2)
Wound Healing Santana-Blank et al. []
Rodríguez-Santana et al.[]
Soft tissues in the rat Diode laser 904nm Promotes wound healing, membrane effect measured by 1H-NMR tau(c)
Neural Stimulation Wells et al. [] Rat sciatic nerve Free electron laser 2.1, 3.0, 4.0, 4.5, 5.0, and 6.1 μm Generated a spatially selective response in small fascicles of the sciatic nerve
Neural Stimulation Jenkins et al. [] Adult rabbit heart Diode laser 1.851μm Induced optical pacing of the adult rabbit heart
Neural Stimulation Izzo et al. [] Gerbils auditory nerve Holmium: YA G laser 2.12 μm Optical radiation stimulated the cochlear response amplitudes
Neural Stimulation Duke et al. [] Rat sciatic nerve Diode laser 1.875μm Hybrid electro-optical stimulation generated sustained muscle contractions and reduced the laser power requirements
Neural Stimulation Shapiro et al. [] HEK-293T cells Diode laser 1.889 μm Altered the membrane electrical capacitance during optical stimulation transiently
Photoaging Darvin et al. [] Human skin Radiator equipped with a water filter 600 ~1500 nm Formed free radicals and decreased the content of β carotene antioxidants
Photoaging Schroeder et al. [] Human dermal fibroblasts Water-filtered IR-A irradiation source 760~14 40 nm Increased expression of MMP-1 in the dermis
Antitum or Action Tsai et al. [] HeLa cervical cancer cell Waveguide Thermal Emitter 3.6, 4.1 or 5.0 μm Caused a collapse of mitochondria l membrane potential and an increase in oxidative stress.
AAntitumorAction Chang et al. [] Breast cancer cells and normal breast epithelial cells. Blackbody source equipped with 3~5 μm filter 3~5 μm Induced G 2 /M cancer cell cycle arrest, remodeled the microtubule network and altered the actin filament formation
Antitumor Action Tanaka et al. [] A549 lung adenocarcinoma cells NIR radiator equipped with a water filter 1.1~1.8 μm Activated the DNA damage response pathway
AAntitumorAction Yamashita et al. [] A431 (vulva), A549 (lung), HSC3 (tongue), MCF7 (breast) and Sa3 (gingiva) cancer cells FIR radiant-panel incubator by coating a carbon/silica/a luminum oxide/titanium oxide ceramic 4~20 μm (maxim um at 7 to 12 μm) Suppressed the proliferation of cancer cells through enhancing the expression of ATF3 gene
Antitum or Action Santana-Blank et al.[] Solid tumor Clinical trial Diode laser 904nm 88% anticancer effect. Ten years follow up
Antitum or Action Santana-Blank et al.[] Solid tumor cytomorphology Diode laser 904nm Selective apoptosis, necrosis, anoikis in tumor tissues of cancer patients
Antitumor Action Santana-Blank et al. [] Solid tumor T2wMRI-Microdensitometry Diode laser 904nm Evidence of interfacial water exclusion zone (EZ) as a predictor of anti-tumor response in cancer patients
Antitumor Action Santana-Blanket al.[] Solid tumor serum levels of cytokines of peripheral leucocyte subsets Diode laser 904nm Immuno-modulation in cancer patients of TNF-α sIL-2R and CD4+CD45 RA+ and CD25+ activated
Brain Neural Regeneration Naeser et al. [] Mild traumatic brain injury NIR diodes 870 nm Improved cognitive function, sleep and post-traumati c stress disorder symptoms
Brain Neural Regeneration Lapchak et al. [] Strokes in embolized rabbits Laser source 808 nm Increased cortical ATP content
Adipose Regeneration Wang, Y., et al. [] human adipose-derived stem cells Diode laser 810 nm
Stimulate the proliferation and differentiation


Contraindication of Infrared Radiation Therapy

Treatment Contraindications forIRR Light Therapy

  • Open wounds
  • Metastatic Lesions
  • Areas of decreased sensation
  • parts of the body with metal implants, like in a total knee replacement of lumbar fusion
  • Near or over a pacemaker
  • the uterus during pregnancy
  • Over the gonads
  • Malignancies and precancerous lesions
  • On patients with vascular abnormalities, i.e. deep vein thrombosis, emboli, severe atherosclerosis
  • The eye directly
  • Over the stellate ganglion
  • For hemophiliacs not covered by factor replacement
  • The spinal cord after laminectomy
  • Directly over metal implants
  • Over an electronic device
  • Tissues previously treated with deep Xray or radiation
  • Tuberculosis (local)
  • Damaged or at-risk skin, i.e. skin rash, eczema
  • Anesthetic areas
  • Excitable tissue,
  • With pregnant women
  • Around the eyes, breasts, or sexual organs
  • Over fractured bones
  • Near or over an implanted electrical stimulation device
  • Women who are pregnant should consult their physician before beginning IRR light therapy treatments.
  • Clients with epilepsy should consult their physician before beginning IRR light therapy treatments.
  • You must wait five days after Botox or cosmetic fillers.
  • Some thyroid conditions.
  • People with a history of skin cancer
  • Systemic Lupus erythematosus should also avoid this kind of treatment.
  • The use of photosensitizing medications (i.e. lithium, melatonin, phenothiazine antipsychotics, and certain antibiotics). 
  • Diseases that involve the retina of the eye 


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Biostimulation Therapy

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