Is the 810 nm or 1064 nm (1070 nm) wavelength better?<\/h1>\n
Across all age groups, the 810nm wavelength has shown to have a deeper and stronger energy disposition than 1064 nm (1070 nm) in a dosimetry study by Harvard Medical School<\/a>, Department of Psychiatry and several other universities<\/a>. Even though 1064 nm (1070 nm) scatters less, it is absorbed more by water molecules, which are abundant in human tissue, especially the brain (70-80% water).<\/p>\n In terms of cellular effects, 810 nm has a stronger effect on mitochondria because photonic absorption by cytochrome c oxidase (CCO)<\/a> peaks around 810nm and declines as the wavelength gets longer. Direct CCO photoexcitation is weaker at 1064 nm and 1070 nm compared to 810 nm because they are off-peak for mitochondria’s CCO absorption, which peaks around 810 nm.<\/p>\n On the other hand, 1064 nm (1070 nm) has a stronger effect on calcium ion channels<\/a>, which 810 nm does not have a strong effect on.<\/p>\n The rest of this article, complete with science references, expands more on the differences, covering well-studied biophysics-based biological effects.<\/p>\n According to\u00a0a transcranial brain photobiomodulation (PBM) study by Harvard Medical School<\/a><\/strong>, Department of Psychiatry, the 810nm wavelength has been found to be superior to other wavelengths, which includes higher wavelengths in the 1070nm range for penetration and dosimetry.<\/p>\n According to this study by Harvard Medical School, the order of penetration and dosimetry effectiveness is:<\/span><\/p>\n 810\u202fnm<\/strong> \u2013 consistently highest across all age groups and regions<\/span><\/p>\n<\/li>\n 850\u202fnm<\/strong> and 1064\u202fnm<\/strong> \u2013 next most effective in most cases<\/span><\/p>\n<\/li>\n 670\u202fnm<\/strong> and 980\u202fnm<\/strong> \u2013 lesser deposition overall<\/span><\/p>\n<\/li>\n<\/ol>\n This Harvard study is also supported by another brain PBM dosimetry study<\/a> by leading Chinese universities, comparing 660 nm, 810 nm, 880 nm and 1064 nm. They discovered that the distribution of photon fluence at 660 and 810\u2009nm within the brain was much wider and deeper than 980 and 1064\u2009nm.<\/p>\n The distribution of photon fluence at 660 nm, 810 nm, 980 nm and 1064\u2009nm. Wang P, Li T. “Which wavelength is optimal for transcranial low-level laser stimulation?” J. Biophotonics. 2019; 12:e201800173. https:\/\/doi.org\/10.1002\/jbio.201800173<\/p><\/div>\n The differences in dosimetry are supported by a well-established biological principle, the body’s first optical window<\/a>. While, the 1064 and 1070nm<\/strong> wavelengths are longer and scatter less, they are more strongly absorbed by water<\/a><\/strong>, which is abundant in biological tissues, especially the human. The brain consists of 70-80% water<\/strong>, and floats in cerebrospinal fluid (CSF)<\/strong> while the rest of the human body is approximately 60% water. This makes wavelengths like 1064 nm and 1070 nm particularly susceptible to water absorption within the brain.<\/p>\n This increased absorption by water can lead to reduced photonic availability and tissue penetration despite the longer wavelength, which the Harvard Medical study<\/a> and Peking Medical University study<\/a> reveal. These studies indicate that 810nm has a higher dosimetry than 1064 nm and by extension, 1070 nm.<\/p>\n The near infrared window or body\u2019s optical window. Image source: Wang, Erica & Kaur, Ramanjot & Fierro, Manuel & Austin, Evan & Jones, Linda & Jagdeo, Jared. (2019). Safety and penetration of light into the brain. 10.1016\/B978-0-12-815305-5.00005-1.<\/p><\/div>\n The Vielight Neuro delivers the deepest tissue penetration among brain photobiomodulation devices.<\/strong> In the demonstration video below with the Vielight Neuro, 810\u202fnm near-infrared light\u2014emitted at an irradiance of 250\u202fmW\/cm\u00b2\u2014can be clearly seen penetrating through the calvaria of a real human skull. This highlights the exceptional transcranial performance of the Vielight Neuro and validates the wavelength\u2019s well-documented ability to reach cortical tissue.<\/p>\n<\/div><\/div><\/div><\/div><\/div> Filmed in darkness, this footage demonstrates how NIR light behaves as it passes through the calvaria (skullcap), offering insight into the distribution of photobiomodulation (PBM) energy and the importance of irradiance.<\/p>\n The test highlights the differences in penetration between the two Vielight Neuro models based on irradiance (mW\/cm2) intensity, showcasing how much light reaches the inner cranial cavity.\" \/> The Vielight Neuro features proprietary Vie-LED technology\u2014highly specialized, custom-engineered LEDs designed to deliver optimal irradiance for brain stimulation without producing excess heat. To ensure safety and efficiency, we\u2019ve intentionally limited the device\u2019s power density to 50% of its maximum potential output. Even still, it features the highest irradiance in the field of brain photobiomodulation according to independent 3rd party tests<\/a>.<\/p>\n<\/div><\/div><\/div><\/div><\/div> The 810nm wavelength<\/strong> is well-known for its strong interaction<\/a> with cytochrome c oxidase (CCO)<\/a><\/strong>, a key enzyme in the mitochondrial respiratory chain. By enhancing the activity of CCO, the 810nm wavelength increases ATP production, reduces oxidative stress, and modulates reactive oxygen species (ROS). These effects are crucial for cellular energy metabolism, neuroprotection, and the promotion of cell survival\u200b.<\/p>\n 1064 nm and 1070nm has a stronger effect on heat-sensitive ion channels<\/strong><\/p>\n On the other hand, wavelengths beyond 900nm, such as the 1064nm and 1070nm wavelengths<\/strong> have a weaker effect on mitochondrial CCO<\/a> but a more direct effect on heat-sensitive ion channels<\/strong><\/a>, due to its potential to cause localized heating. Activation of these channels<\/a> can lead to increased calcium influx, which is crucial for various cellular processes, including neurotransmitter release, gene expression, and neurogenesis.<\/p>\n The effects of red to NIR light energy on mitochondria Ref: Original: \u201cBasic Photomedicine\u201d, Ying-Ying Huang, Pawel Mroz and Michael R. Hamblin, Harvard Medical School. Current design: Vielight In<\/p><\/div>\n The 810nm wavelength is particularly effective in targeting cytochrome c oxidase<\/a>, which is a critical component of the mitochondrial electron transport chain. This wavelength is more efficiently absorbed by cytochrome c oxidase, leading to a robust activation of the mitochondrial respiration process. As a result, there is an increase in ATP production, which supplies energy to cells and supports various cellular functions. The 810nm wavelength is especially effective in reaching superficial and cortical brain regions, promoting enhanced cellular metabolism and function in these areas.[2<\/a>]<\/sup><\/p>\n The 1064 nm and 1070 nm wavelengths, while still within the near-infrared (NIR) spectrum, does not interact with cytochrome c oxidase<\/a> as effectively as the 810nm wavelength. The absorption by mitochondrial chromophores decreases significantly<\/a> as the wavelength increases beyond 810nm.[5<\/a>]<\/sup> Consequently, the 1070nm wavelength has a reduced effect on mitochondrial activation when compared to 810nm. Instead, the 1070nm wavelength might exert its effects through other mechanisms, such as potential thermal effects<\/a> and heat\/light ion gated channels.<\/p>\n At the cellular level, the 810nm wavelength has shown considerable efficacy in promoting cortical neurogenesis<\/a>\u2014the process by which new neurons are formed in the brain. This wavelength is also known for its anti-inflammatory effects, which can help reduce neuroinflammation and support the brain\u2019s healing processes. The 810nm wavelength is well-suited for applications targeting the outer layers of the brain, where it can stimulate cellular repair mechanisms, reduce oxidative stress, and promote overall Brain wellness.<\/p>\n Flowchart of Differences in Cellular Mechanisms:<\/span><\/strong><\/p>\n 1064\/1070 nm \u2192 water-mediated microheating \u2192 TRP gating\/membrane-capacitance effects \u2192 Ca\u00b2\u207a influx.<\/strong><\/p>\n<\/li>\n 810 nm \u2192 CCO-mediated mitochondrial signaling \u2192 downstream Ca\u00b2\u207a effects.<\/strong><\/p>\n<\/li>\n<\/ul>\n<\/div><\/div><\/div><\/div><\/div> Cytochrome c oxidase within mitochondria has distinct absorption bands in the visible red (~660\u202fnm) and near-infrared (810\u202fnm) regions. Studies consistently show <\/a>that absorption drops off as you shift to longer NIR wavelengths around the 1000 nm range like 1064\u202fnm (1070nm).<\/span><\/p>\n<\/li>\n The absorption bands of CCO become much weaker at wavelengths greater than 900 nm<\/a>, which suggests that alternative chromophores must exist significantly<\/span>.<\/p>\n<\/li>\n<\/ul>\n At ~1064\u202fnm (1070nm), water (the dominant tissue component) is absorbed significantly<\/a> versus 810\u202fnm. This leads to greater attenuation (loss) of photons before they can reach and excite CCO.<\/span><\/p>\n<\/li>\n<\/ul>\n Calcium channels themselves don\u2019t meaningfully \u201cabsorb\u201d 1064 nm light. What happens at ~1064\u20131070 nm is mainly photothermal couplin<\/a>g – <\/strong>water is absorbed significantly at longer NIR wavelengths (> 1000 nm), producing tiny, rapid temperature rises that gate heat-sensitive TRP calcium channels <\/strong>(e.g., TRPV1\/2\/4) and\/or change membrane capacitance, which in turn drives Ca\u00b2\u207a influx.<\/p>\n By contrast, 810 nm couples primarily to cytochrome-c-oxidase (CCO)<\/strong> with much weaker water heating, so Ca\u00b2\u207a effects there are usually downstream of mitochondrial signaling, not direct channel gating.<\/p>\n<\/div><\/div><\/div><\/div><\/div> A\u00a0recent study<\/strong>\u00a0<\/a>on vascular hemodynamics and cytochrome c oxidase redox activity (not on the brain, but on arms) by the Department of Bioengineering, University of Texas at Arlington examined the effects of different wavelengths within this range with<\/p>\n Results<\/strong><\/span><\/p>\n These findings are encouraging for us \u2013 our Vielight Neuro\u2019s rear 810nm LED transcranial diodes generate\u00a0\u2248200-300 mW\/cm2<\/sup><\/strong>, which surpasses the power density of\u00a0\u2248135 mW\/cm2<\/sup><\/strong> used in the study. It underscores our commitment to fewer well-placed but sufficiently powerful diodes vs many weaker diodes.<\/p>\n An important takeaway is the importance of irradiance values (mW\/cm2 <\/sup>) in this study.<\/p>\n<\/div> Irradiance\u2014also referred to as power density or light intensity – is a measure of how much light energy reaches a surface per unit area, typically expressed in milliwatts per square centimeter (mW\/cm\u00b2). In photobiomodulation (PBM), including brain PBM, irradiance determines how much photonic power is delivered to the tissue.<\/p>\n While using an effective wavelength (such as 810 nm, 1064 nm, or 1070 nm) is essential for targeting chromophores like cytochrome c oxidase, the biological response and penetration depth depends just as much on irradiance<\/strong>. Without sufficient power density, even the correct wavelength may fail to penetrate tissue effectively or trigger meaningful cellular effects. Low irradiance can result in sub-therapeutic penetration and doses, while excessively high irradiance may lead to phototoxicity or energy wastage.<\/p>\n In a published review study of over 2133 brain photobiomodulation studies<\/strong>, from which 97 studies were included, the average irradiance or power density was around 250 mW\/cm2<\/sup><\/a><\/strong><\/p>\n As a point of comparison, the average surface irradiance of near-infrared (NIR) light in natural sunlight is approximately 45 mW\/cm\u00b2 – <\/strong>a helpful benchmark when evaluating PBM device output.<\/p>\n In short, optimal photobiomodulation requires both the right wavelength and the right irradiance to reach the target tissue and activate mitochondrial responses.<\/strong><\/p>\n In a 2024 systematic review<\/strong><\/a> that screened 2,133 records and included 97 brain-PBM studies, reported power densities typically clustered around ~250 mW\/cm\u00b2<\/strong> (especially under physiological conditions).<\/p>\n This is a snapshot comparison of independently measured irradiance<\/strong> by photonics labs by the PBM Foundation between commercial devices with the 810nm wavelength and the 1064 nm, 1070nm wavelengths:<\/p>\n<\/div><\/div><\/div> Data Source: The PBM Foundation’s Device Testing Portal ( Link 1<\/a> | Link 2<\/a> )<\/p>\n<\/div><\/div><\/div> Vie-LED technology is unique and is engineered to generate a laser-like irradiance<\/strong> profile but with the safety of LEDs.<\/p>\n
\nDoes 810 nm or 1064 nm (1070nm) penetrate deeper into the brain?<\/h2>\n
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Visual Proof: Near-Infrared Light Penetrating the Skull with Vielight Neuro 4<\/h2>\n
Differences in cellular effects between 810nm and 1070nm<\/h2>\n
810nm has a stronger effect on mitochondria, cytochrome C oxidase (CCO)<\/h4>\n
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Mitochondrial Activation<\/strong><\/h3>\n
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Neurogenesis<\/strong><\/h3>\n
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Why mitochondria absorbs 810\u202fnm more than 1064\u202fnm (1070nm)<\/h2>\n
1. Spectral absorption properties of cytochrome c oxidase (CCO) within mitochondria<\/strong><\/h4>\n
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2. Reduced photon availability at 1064\u202fnm (1070 nm)<\/strong><\/h4>\n
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Why calcium ion channels absorb more 1064\u202fnm (1070nm) versus 810 nm<\/h2>\n
Research validation of 810nm LEDs vs lasers<\/h2>\n
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Wavelength alone isn\u2019t enough – irradiance matters.<\/h2>\n
Key Concepts:<\/strong><\/h3>\n
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A Comparative Snapshot<\/h2>\n<\/div>
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<\/a><\/span><\/div>Irradiance \/ Power Density Comparison<\/h2>\n<\/div>