Demystifying and understanding laser therapy

Continued research and collaboration between scientists, clinicians and regulatory bodies will unlock the full potential of laser therapy and ensure its safe and effective integration into modern medicine.

Lasers, once a futuristic concept, have become an integral part of modern medicine. Their ability to deliver concentrated beams of light with precision has revolutionized various therapeutic applications. This article explores laser therapy’s principles, applications and ramifications for the future.¹

Understanding laser therapy: A spectrum of light and power

Laser, short for light amplification by stimulated emission of radiation, functions by emitting concentrated beams of monochromatic light, meaning they consist of a single, specific wavelength. This characteristic enables precise targeting of tissues, making these beams valuable tools.

The therapeutic effect of a laser depends heavily on its wavelength. Common wavelengths used in laser therapy include:

• Infrared (IR): Penetrates deeply into tissues, promoting healing, reducing inflammation and managing pain.
• Red: Readily absorbed by tissues, stimulating cellular activity and promoting tissue repair.
• Near-infrared (NIR): Offers more penetration than red light, reaching bones, muscles and underlying tissues.

Understanding laser wavelengths

There is no magical wavelength science has proven to be the best or most effective for all conditions. All wavelengths or lasers are different, so I strongly recommend if you are in the market purchasing one with treatment versatility and power. This will give you the best chance to get the results you are looking for in the shortest amount of treatment time. With this said, some wavelengths are better choices than others depending upon what you are trying to accomplish clinically.²

Aiming beams: 635-650nm are visible red wavelengths used as a primary tool for correct spot size for treatment application. Some manufacturers use these as treatment beams, but their penetration is limited to millimeters, so they most commonly only treat the skin. In the electromagnetic spectrum of light below you will see that under 700nm laser light is visible red and 700nm and above becomes infrared light, which penetrates deep into tissues. (Figure 1)

Treatment beams: 800-1,064nm are infrared wavelengths, which are invisible to the naked eye. In fact, on some diode lasers, the software enables you to turn off the aiming beam; if you turn on the laser you still feel the thermal side effect, which proves the infrared beams are on and working. Each wavelength is independent of others and functions solely on its own. Some lasers allow you to turn certain wavelengths on and off while others are fixed. A true dual-wave, tri-wave or quad laser allows you to set each wavelength to the desired frequency.

Below is a breakdown of the most common treatment wavelengths and what they are best used for.

800-810nm are deep-penetrating infrared beams manufacturers claim go the deepest at 5-6cm with less absorption of water content, thus resulting in less of a thermal effect. This wavelength is used most often for treatment of deep tissue, vascular tissue, dark skin and other dermatological applications.

905-915nm are mid-level wavelengths with tissue penetration of 3-4cm with a mix of benefits, including tissue healing, nitric oxide release and pain relief.

970-980nm are infrared beams manufacturers claim penetrate 4-5cm with high absorption of water content that leads to increased fluid circulation with a robust analgesic effect. This wavelength is a good choice for pain reduction, improved range of motion, increased circulation, inflammation control and healing of avascular tissue, such as the spinus process.

1,064nm is a relatively new low thermal wavelength with a manufacturer-claimed depth of penetration of 7-9cm. The penetration ability without much of a thermal side effect is attractive for many reasons, including a slower application to the skin. Knowing and understanding laser physics, I believe this could be an efficient path to tissue healing without an excessive amount of the heating side effects patients might experience with high-power treatment diodes.³ Research explains how since the refraction index is much lower with the 1,064nm wavelength, it has the potential to penetrate the skin more deeply than the 810nm and 980nm spectrums of light. (Figure 2)

The following presents some guidelines to help you choose the best laser for your practice. To treat any condition, you want multiple wavelengths with as much wattage out of each diode as possible. However, if you would like to focus on one specific treatment niche, a single diode system or dual-wave may be right for you. Many believe more power per wavelength produces more penetration and more cell stimulation at those individual depths.

Beyond wavelength, the US Food and Drug Administration’s classification system for lasers categorizes them based on their potential for causing harm:

• Class I and II: Emit low-powered beams with minimal risk.
• Class III A or B: Can cause skin or eye injury if used improperly.
• Class IV: Require stringent safety measures due to the risk of burns and eye damage.

Low-level laser therapy: A gentle approach

Low-level laser therapy (LLLT), often referred to as cold laser therapy or photobiomodulation, uses Class III lasers with low power outputs. It is a non-thermal therapy, meaning it does not generate heat. Instead, it is believed to work by stimulating cellular processes, promoting tissue repair and reducing inflammation. LLLT has been studied for various applications, including:

• Pain management: Chronic pain, postsurgical pain and pain associated with arthritis are some of the conditions for which LLLT may offer relief.⁴
• Wound healing: Studies suggest LLLT can accelerate wound closure and improve healing outcomes.⁵
• Skin conditions: Acne, psoriasis and eczema are some skin conditions in which LLLT may be used to manage symptoms.

High-powered lasers: A new frontier

The development of high-powered Class IV lasers, with outputs from .1-60 Watts (60,000mW) continuous, has opened doors for new possibilities. The first FDA 510(k) safety clearance was given in 2003 at 7.5 Watts continuous.⁶ These lasers offer deeper tissue penetration and potentially broader applications, but more research is warranted to fully understand their efficacy and safety profile for various conditions.

Frontiers of laser therapy

High-powered lasers are being explored for a range of potential applications,^7,8 including:

• Cancer treatment: Laser therapy may play a role in ablating tumors or relieving symptoms associated with cancer.⁹
• Neuromodulation: Emerging research suggests lasers may stimulate or inhibit specific neural pathways, offering promise for treating neurological conditions, such as depression and pain.¹⁰
• Regenerative medicine: Laser therapy may promote tissue regeneration, potentially aiding in procedures, such as bone repair and nerve regenesis.¹¹

The road ahead: Balancing innovation with evidence-based practice

The advancements in laser technology are undeniable. However, it is vital to acknowledge the limitations in our current understanding. Larger clinical trials are needed to determine the optimal parameters for high-powered laser therapy and establish its efficacy for various conditions. Additionally, long-term safety data is essential to ensure patient well-being.

As laser technology continues to evolve, maintaining a balanced approach is important. While the vast potential of high-powered lasers is exciting, prioritizing patient safety and basing treatment decisions on sound scientific evidence remains paramount.

David Bohn, DC, graduated from National University of Health Sciences in 1988 and has since been in continuous practice. Since 2004, Bohn has pursued development of both documentation and X-ray analysis software. He has extensive experience developing, marketing and maintaining a successful practice. Bohn is an instructor for KDT Decompression Therapy Seminars.

References

1. International Laser Therapy Association (ILTA). 2023. https://www.ilta.academy/ . Accessed August 27, 2025.

2. Penberthy, WT, Vorwaller CE. Utilization of the 1064nm wavelength in photobiomodulation: A systematic review and meta-analysis. J Lasers Med Sci. 2021;12:e86. https://pmc.ncbi.nlm.nih.gov/articles/PMC8837867/ . Accessed September 17, 2025.

3. Marshall RP, Vlková K. Spectral dependence of laser light on light tissue interactions and its influence on laser therapy: An experimental study. iMedPub Journals. 2020;5(1):1. https://biomedicine.imedpub.com/ . Accessed August 27, 2025.

4. Cotler, HB, et al. The use of low-level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthop Rheumatol. 2015;2(5):00068. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4743666/ . Accessed August 27, 2025.

5. Guidelines for low-level laser therapy. 2020. World Association of Laser Therapy (WALT). https://waltpbm.org/ . Accessed August 27, 2025.

6. Snyder M. High-power laser therapy. 2003. Avicenna. https://highpowerlasertherapy.com/medical-professionals/ . Accessed August 27, 2025.

7. Laser Safety Guidelines. 2018. American Society for Laser Medicine and Surgery (ASLMS). https://www.aslms.org/ . Accessed August 27, 2025.

8. Laser hair removal. 2021. American Academy of Dermatology. https://www.aad.org/public/cosmetic/hair-removal. Accessed August 27, 2025.

9. Lasers to treat cancer. Updated June 2021. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/surgery/lasers. Accessed September 17, 2025.

10. Krishna V, Fasano A. Neuromodulation: Update on current practice and future developments. Neurotherapeutics. 2024;21(3):e00371. https://pmc.ncbi.nlm.nih.gov/articles/PMC11103215/. Accessed September 17, 2025.

11. Dutra Alves NS, et al. Advances in regenerative medicine-based approaches for skin regeneration and rejuvenation. Front. Bioeng. Biotechnol. 2025;13:1527854. https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2025.1527854/full. Accessed September 17, 2025.