Better Than Blue Light, Better Than High LUX — TUO Products are the Only Circadian Light Therapy That Works in Real-World Conditions

Partnered with the University of Washington

Partnered with one of the world's top research centers for vision and neuroscience

One of the world's top research centers for vision and neuroscience


Who is TUO? TUO is a healthy lighting technology startup that is the exclusive partner of the University of Washington to help commercialize their circadian lighting technology.

Our lighting technology effectively synchronizes your biological schedule to our daily schedule for improved sleep, energy, and health.  

We offer this in a smart LED lightbulb and App to easily use anywhere in your home or office like any other light - only healthier.

University of Washington Press Release including TUO partnership:


Let there be 'circadian' light | Newsroom 

Image of the rising sun



What is Circadian Rhythm and How does it work?

Circadian rhythms are our body's internal clock, guiding our sleep and wake cycles to align with the day-night cycle. These rhythms rely on external cues, with light being the primary signal that syncs our internal clock, located in the brain's Suprachiasmatic Nucleus (SCN). This master body clock regulates various bodily functions, including digestion, heart rate, and muscle activity.

When our circadian rhythms are disrupted, such as when we travel across time zones or experience daylight saving time changes, we may feel hungry at odd times or be at a higher risk of health issues like heart attacks. However, these rhythms are adaptable and can adjust based on exposure to daylight, varying in duration and timing depending on the season and location.

Understanding the precise role of light in influencing circadian rhythms has been a focus of scientific research for years. In 2020, researchers at the University of Washington's Jay Neitz Lab made a breakthrough discovery, uncovering the specific cells and circuitry connecting the eye to the SCN. This newfound knowledge has paved the way for innovative approaches to designing lighting solutions that effectively influence circadian rhythms.

"While sunrise lights, blue lights, and devices for seasonal affective disorder (SAD) have all attempted to replicate the benefits of natural light, they often fall short due to a lack of comprehensive scientific understanding," emphasizes Professor Jay Neitz, a renowned color vision researcher and ophthalmology professor at the UW School of Medicine. Incorporating robust scientific data into the development of circadian-influencing lighting products is crucial for optimal effectiveness.


circadian circuit 



What is the healthiest light for circadian rhythm synchronization, SAD, health, and sleep?

The healthiest light for synchronizing circadian rhythms, managing Seasonal Affective Disorder (SAD), promoting overall health, and enhancing sleep quality is characterized by specific violet and orange hues, reminiscent of the colors observed at dawn. This represents a significant departure from the conventional approach that relied on blue-enriched white lights or high-intensity 10,000 lux white light therapy lamps for decades. 

Our eyes, equipped with three types of cone photoreceptors in the retina, are particularly sensitive to these violet and orange color changes, akin to those seen during sunrise. As we gaze around or blink, these cones relay potent signals to our Suprachiasmatic Nucleus (SCN), informing it about the prevailing time of day. Considering the abundance of over 7 million cone photoreceptors in our retina, envisioning the multitude of evolving color signals they capture when exposed to a morning sky is effortless. In contrast, blue lighting technologies primarily target a much smaller population of approximately 4-7 thousand ipRGC cells.

healthiest light for circadian rhythm synchronization, SAD, health, and sleep



The TUO light really works. The University of Washington has published a paper that sought to compare bright white light, blue light, and the color alternating light used in TUO. White and blue light approaches purport to activate melanopsin directly on the melanopsin ganglion cells downstream of our color cones. Therefore, the 3 light conditions were designed to equally activate melanopsin (White and Blue light claims) to isolate the impact of the color opponent signals on the melanopsin ganglion cells that transmit signals to the SCN. 

A 2-hour exposure of each light produced:

White: No change in circadian rhythm.

Blue: 40 minute advance

Color alternating (TUO): 1 hour and 20 minute advance


Normalized melatonin concentration - B
Normalized Melatonin Concentration - C
Normalized Melatonin Concentration - D


“The color of the sky at sunrise and sunset is the ideal cue for synchronizing one’s internal body clock to solar time. The intensity of light overhead can vary greatly for many reasons making it an unreliable indicator of the time of day, but the orange color of the sky at the horizon always indicates that it is sunrise or sunset. Retinal ganglion cells act as feature detectors. The color opponent inputs to ipRGCs confer the ability to act as sunrise/sunset detectors. The orange color of the horizon that characterizes the rising and setting sun produces a color contrast with the blue sky. The blue and orange parts of the image on the retina produced by the sunset moving across the receptive field of an ipRGC activates the transient color-opponent response very strongly.”


James Kuchenbecker, Alex Neitz, Alicia Rice et al. Toward an indoor lighting solution for social jet lag, 17 March 2023, PREPRINT (Version 1) available at Research Square []



How does the TUO light use this breakthrough in circadian biology understanding?

The TUO circadian light leverages groundbreaking insights from circadian biology through its patented lighting technology. By rapidly pulsing between two specific spectrums, TUO activates an optimal circadian entrainment signal to the Suprachiasmatic Nucleus (SCN). This innovative approach mimics the experience of observing the changing colors of a dawn sky within the confines of your home or office, effectively replicating the natural circadian light present during sunrise.

Given the remarkable sensitivity of our cone photoreceptors to light, even at low levels such as 1 lux, TUO achieves this circadian simulation at typical comfortable lighting levels. In most home or office environments, lighting levels hover around 250 lux, rendering the need for intense 10,000 lux bright lights unnecessary with TUO's healthy lighting solution.


Normalized absorbance - By rapidly pulsing between two specific spectrums, TUO activates an optimal circadian entrainment signal to the Suprachiasmatic Nucleus (SCN).



The time of day you see circadian light is critical.  The SCN is only sensitive to circadian cues in the early morning and late evening and they have the opposite effect on our circadian rhythm adjustment. Light during the majority of the day is not signaling your circadian cycle very much at all, though it does signal other non-circadian systems in the brain for mood, libido, mental acuity, and more. Scientists have subjected people to light at all times of day and night to see when and how much our circadian rhythms change. It showed that we are most sensitive at the times that align with daily dawn and dusk.  The effect is also opposite where in the early morning our circadian rhythms are advanced (we wake up and want to wake up earlier the next day), whereas in the evening our circadian rhythms are delayed (we want to stay awake and wake up later the next day). 


Circadian rhythm and human body



You need different light therapy depending on the time of day. With the TUO app, users can schedule their custom circadian schedule based on their schedule and needs.  The circadian light therapy schedule will deliver the appropriate lighting therapy mode at the right time every time you turn the TUO lightbulb on.  Each lighting mode is designed to synchronize your internal circadian rhythm to the time you routinely wake up and sleep every day. Our Wake mode sends powerful circadian signals to sync that time to wake up at the same time each day, offsetting social jetlag, morning sleepiness, and energizing your mind and body for the day. The Active mode energizes you throughout the day and combats Seasonal Affective disorder, elevating energy, and mental acuity.  Calm is a perfectly balanced light therapy designed to not activate the circadian system and reverse the positive effects of the morning Wake therapy at any brightness.  You can still use at normal light levels to read a book before bed without worrying it will keep you awake.


TUO app's 3 circadian light modes  TUO app sets the perfect light therapy schedule  



Everyone's circadian rhythm is slightly different in length and timing.  Children and teens' circadian rhythms are typically 25 hours or longer, whereas seniors can be 23 hours or shorter. Our circadian rhythms naturally get shorter as we age. The majority of our adult life is typically about 24.5 hours long, which doesn’t match our 24 hour schedules. We know this from our own experiences, high school kids sleep all the time but grandpa is always up early. This means that most of us under artificial lighting, without the proper light cues our bodies need, have 30 minutes of jetlag everyday, called “social jetlag”. The term social jetlag is the discrepancy between biological time and social times, mainly from social obligations such as school or work that are on a perfect 24 hour schedule. This is why alarm clocks exist - to force our bodies into action before it's biologically and naturally ready every morning.

Circadian rhythm differences




TUO makes it easy for everyone to get a perfect circadian rhythm with custom light therapy. The TUO app allows users to enter their age and chronotype which can be applied to each room.


TUO mobile app



What research and peer reviewed papers are relevant to your healthy lighting and circadian synchronization lighting?

TUO Video with our scientific partners explaining the science behind TUO:


University of Washington Press Release with video interviews with researchers and 3D animations of cone to ganglion cell pathways:




Peer reviewed papers from, or related to, our University of Washington scientific partners

James Kuchenbecker, Alex Neitz, Alicia Rice et al. Toward an indoor lighting solution for social jet lag, 17 March 2023, PREPRINT (Version 1) available at Research Square

Rivera AM, Huberman AD. Neuroscience: Neuroscience: A Chromatic Retinal Circuit Encodes Sunrise and Sunset for the Brain. Curr Biol. 2020 Apr 6;30(7):R316-R318. doi: 10.1016/j.cub.2020.02.090. PMID: 32259506; PMCID: PMC8407369. Andrew Huberman is an Associate Professor at Stanford University and neuroscience podcast star that wrote this ‘dispatch’ (summary and evaluation of the importance of research or discovery) on the University of Washington research below.

Patterson SS, Mazzaferri MA, Bordt AS, Chang J, Neitz M, Neitz J. Another Blue-ON ganglion cell in the primate retina. Curr Biol. 2020 Dec 7;30(23):R1409-R1410. doi: 10.1016/j.cub.2020.10.010. PMID: 33290703; PMCID: PMC8447961.

Patterson SS, Kuchenbecker JA, Anderson JR, Neitz M, Neitz J. A Color Vision Circuit for Non-Image-Forming Vision in the Primate Retina. Curr Biol. 2020 Apr 6;30(7):1269-1274.e2. doi: 10.1016/j.cub.2020.01.040. Epub 2020 Feb 20. PMID: 32084404; PMCID: PMC7141953.

Pauers MJ, Kuchenbecker JA, Neitz M, Neitz J. Changes in the colour of light cue circadian activity. Anim Behav. 2012 May 1;83(5):1143-1151. doi: 10.1016/j.anbehav.2012.01.035. Epub 2012 Feb 18. PMID: 22639465; PMCID: PMC3358782.

Dacey, Dennis. (1996). Circuitry for Color Coding in the Primate Retina Proceedings of the National Academy of Sciences of the United States of America. 93. 582-8. 10.1073/pnas.93.2.582.