I. Introduction
Red light therapy devices, as non‑invasive phototherapy equipment, have rapidly gained popularity in medical rehabilitation and home health in recent years. With increasing export and domestic compliance requirements, photobiological safety has become a core threshold for market access of red light therapy devices. The IEC 62471 standard, as the globally applicable basis for photobiological safety assessment, provides a clear technical framework for the safety and compliance of red light therapy devices.
II. Introduction to the IEC 62471 Photobiological Safety Standard
IEC 62471 is the standard “Photobiological safety of lamps and lamp systems” published by the International Electrotechnical Commission. It applies to all incoherent broadband electrical light sources, including LEDs but excluding lasers, with a wavelength coverage range of 200 nm to 3000 nm. The standard clearly specifies optical radiation exposure limits, reference measurement techniques, and classification schemes, classifying light sources into four groups: Exempt Group, Risk Group 1 (low risk), Risk Group 2 (moderate risk), and Risk Group 3 (high risk). The EU has adopted it as EN 62471, and China has equivalently adopted it as GB/T 20145. Since September 2010, LED products are no longer covered by IEC 60825‑1 and must undergo photobiological safety assessment in accordance with IEC 62471.
III. Principles of Red Light Therapy Devices
The operating principle of red light therapy devices is based on the biostimulatory effects of the 600‑700 nm red visible light band. Light in this band has relatively deep penetration into human tissue. Mitochondria in cells serve as the primary absorbers; under red light, catalase activity significantly increases, thereby promoting cell metabolism, accelerating protein synthesis and adenosine triphosphate (ATP) decomposition, and aiding cell regeneration and repair of damaged tissue. At the same time, through photochemical and photoelectromagnetic reactions, red light acts deeply on vascular tissue, lymphatic tissue, and nerve endings, improving microcirculation, promoting lesion repair, and providing antibacterial, anti‑inflammatory, and analgesic effects.
IV. Applications and Market Prospects of Red Light Therapy Devices
The application scenarios of red light therapy devices have expanded from professional medical use to home health. Clinical studies show that red light therapy devices have confirmed adjunctive therapeutic effects in diabetic foot care and wound repair after excision and suturing, capable of reducing pain, alleviating oedema, and lowering scar formation rates. In 2026, the global red light therapy device market is projected to reach USD 4.72 billion, with the Asia‑Pacific region accounting for 38.4% and ranking first, where China contributes 62.1% of the Asia‑Pacific regional sales. Portable home‑use devices account for over 51% of sales on e‑commerce channels, becoming the fastest‑growing sub‑market.
V. IEC 62471 Photobiological Safety Testing Content and Requirements for Red Light Therapy Devices
IEC 62471 testing for red light therapy devices must cover optical radiation hazard assessment across the full spectrum of ultraviolet, visible, and infrared. Core test items include:
Photochemical UV hazard (200‑400 nm)
Near‑UV hazard (315‑400 nm)
Retinal blue light hazard (400‑500 nm)
Retinal thermal hazard (780‑1400 nm)
Infrared hazard to the eye (780‑3000 nm)
Skin thermal hazard (380‑3000 nm)
For red light therapy devices, although their dominant wavelength lies in the red visible band, the short‑wave components potentially present in the light source and the thermal effects caused by high power density still require rigorous assessment. Testing must be conducted in a darkroom using high‑precision spectroradiometers, performing spectral scanning and weighted calculations in accordance with the standard‘s specified measurement distance (typically 200 mm) and field‑of‑view conditions.
VI. IEC 62471 Photobiological Safety Testing Process for Red Light Therapy Devices
The complete testing process consists of four stages:
1. Preliminary preparation: The manufacturer provides 2‑3 mass‑production samples, along with product manuals, key component lists, and other documentation.
2. Determination of test conditions: Based on the actual usage scenario, set the assessment distance (minimum 200 mm) and measurement field of view, and select the large‑source or small‑source method according to the light source‘s angular subtense.
3. Spectral radiation measurement: Scan the full‑band spectral distribution, calculate the weighted irradiance or radiance values for each hazard type, and compare them with the standard limits.
4. Classification and report issuance: Determine the product hazard group based on the measurement results and issue a test report with CNAS/CMA accreditation as the technical basis for compliant market launch.
VII. Shenzhen Zhongwei Inspection: Professional Photobiological Safety Testing Service Provider
Shenzhen Zhongwei Inspection is a professional optical product testing and certification body in China, focusing on optoelectronic product safety and performance testing for over ten years, and operating a state‑of‑the‑art optical laboratory. The organisation was comprehensively upgraded from a leading domestic laser testing laboratory, with testing capabilities covering the full spectrum from ultraviolet, visible, to infrared, and a power measurement range spanning from picowatts to tens of kilowatts. For the photobiological safety needs of red light therapy devices, Shenzhen Zhongwei Inspection provides IEC 62471, EN 62471, and GB/T 20145 photobiological safety testing services, covering all assessment items including UV hazard, blue light hazard, and retinal thermal hazard. In addition to photobiological safety testing, the organisation also provides electrical safety testing – from laser product safety testing to phototherapy product safety testing – offering a complete one‑stop compliance service to support compliant market launch.
