| Don's Home  Health  Light Therapy | 
Muscle and Skin Pain:
Deep Red 630 670 nm or 650 nm plus Near Infrared (NIR)850 nm
Deep-tissue optical imaging of near cellular-sized features | nature.com sites A study using NIR-I imaging reported a maximum penetration depth through tissue of ~3.2 cm (1.5in)
Photobiomodulation (PBM) in human muscle tissue: an advantage in sports performance? ncbi.nih.gov compared studies of the results of 2 kinds of Light Therapy both after injury and before exercise to improve performance and prevent injury and reduce delayed onset muscle soreness (DOMS).
They looked at 2 types 
Low-level laser therapy (LLLT) (800 nm and 970 nm) or light-emitting diode therapy (LEDT) (850 nm and 660 nm).
Several studies  showed a decrease of CK levels.
CK (Creatine Kinase protein) can rise after muscle injury.
There were studies showed positive results with both LLLT and LEDT.
Some studies had ambiguous effects (both positive and no effects.
  Conclusion: PBM Works:
  
Red Light Photobiomodulation Buyers Guide | PrimalHacker.com has a lot of technical information supporting JOOVV in the red light visible spectrum 600-700 nm wavelength.
They are supporting Joovv
 
Exact action spectra for cellular responses relevant to phototherapy PubMed.gov references articles on various biological responses of HeLa cells irradiated with monochromatic light of 580-860 nm.
 Devices
 Amazon Search
Amazon Search
There are many companies selling a handheld red-light/IR  LED light therapy wand, which held touching to 1 inch away from  the target area for up to 5 minutes at a time, 1 (light pain) - 3 (deep pain) times a day will efficiently heal and relieve your pain within 1 month.. 
NovaaLab Pro, Tometc , TENDLITE,  Quantum Rejuvenation all seem to be the same thing for around $150 - 630nm, 660nm & 850nm
FDA Class 3 Light Therapy
wavelingth: 630, 660 nm Deep Red light and 850 nm Infrared
Irradiance: 141 mW/cm3
Illumance: 180 lux at 15 cm ( 6 in.)
RedTonic $120 and Lifepro $100 apear to be the same but cheaper.
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Joovv Red Light Therapy is a large red light display
Curious about Joovv? Get the lowdown on red-light therapy first | CNET
 
 Terms:
 
 LED - Light Emitting Diode
 LLRLT - Low Level Red-Light Therapy
 Low-level laser therapy (LLLT) (800 nm and 970 nm)
 light-emitting diode therapy (LEDT)
NIR-I: 700Ð900 nm
NIR-II: 1000Ð1700 nm
nm - NanoMeter - 10-9 meters - 1,000 µm (micron)
PBM - PhotoBbioModulation
TENS | UK NHS (transcutaneous electrical nerve stimulation)
 Links:
Red light therapy and psuedoscience | Reddit says it doesn't go that deep.
 TENS
 
Infrared Heating in food