A healthier light, backed by real science

TUO is a healthy lighting technology startup and the exclusive commercialization partner for the University of Washington's patented circadian lighting research. Our smart LED bulb and companion app deliver precisely timed light therapy proven to synchronize your body's internal clock — improving sleep, energy, and long-term health.

Unlike sunrise lamps, blue light glasses, or 10,000-lux therapy boxes, TUO is engineered around a 2020 breakthrough that finally revealed the specific cells and neural pathways linking the eye to the brain's master clock.

Your body runs on a 24-hour clock — light is the key

Circadian rhythms are the biological schedules that govern your sleep, energy, digestion, heart rate, and dozens of other systems. The master timekeeper is a tiny region in the brain called the Suprachiasmatic Nucleus (SCN) — and light is its primary input signal.

When your circadian rhythm is out of sync — from jet lag, shift work, or simply the mismatch between your natural sleep schedule and your alarm clock — the downstream effects are real: poor sleep, low energy, mood disruption, and increased disease risk.

"While sunrise lights, blue lights, and devices for seasonal affective disorder have all attempted to replicate the benefits of natural light, they often fall short due to a lack of comprehensive scientific understanding."

— Professor Jay Neitz, UW School of Medicine, Ophthalmology

In 2020, researchers at the Jay Neitz Lab made a landmark discovery: they identified the precise cells and circuitry connecting the eye to the SCN. This changed everything about how light therapy should be designed.

The newly discovered circuit: cone photoreceptors → amacrine cell relay → ipRGC cells → optic nerve → SCN master clock

It's not blue light. It's the colors of sunrise.

For decades, circadian light therapy focused on blue light — targeting a small population of approximately 4,000–7,000 specialized retinal cells (ipRGCs). It works, but only weakly.

The UW research revealed a far more powerful mechanism: the color-opponent signals generated by the 7 million cone photoreceptors in your retina. These cones are acutely sensitive to the shift between violet and orange wavelengths — the exact color contrast of dawn and dusk.

When warm orange light meets cool violet sky, your cones fire signals to the SCN that say, unambiguously: it's sunrise. This is the signal your body has evolved over millions of years to trust above all others.

In a controlled study, TUO's light outperformed blue light by 2×

The University of Washington published a study comparing three lighting conditions — all equated for melanopsin activation to isolate the effect of color-opponent signals. Each participant received 2 hours of exposure. Results measured via salivary melatonin (DLMO):

"The orange color of the sky at the horizon always indicates 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."

— Kuchenbecker, Neitz, Rice et al., Journal of Biological Rhythms, 2024

Mimicking dawn in your living room — at normal brightness

TUO's patented bulb rapidly alternates between two specific light spectrums, generating the same color-opponent signal your cones send to the SCN when you watch a sunrise. This activates the most powerful known pathway for circadian entrainment.

Because cone photoreceptors respond even at 1 lux, TUO achieves full circadian effect at comfortable room lighting levels (around 250 lux). No need to stare into a blinding 10,000-lux lamp.

The right light at the right time — automatically

The SCN is only sensitive to circadian light cues at two windows: early morning and late evening. Light during the middle of the day has little circadian effect — though it still supports mood, focus, and energy through other brain pathways.

And the direction matters: morning light advances your clock (you wake earlier, more naturally), while evening light delays it (you stay alert longer).

Three modes. One schedule. Set it once.

The TUO app lets you enter your wake time, sleep time, age, and chronotype. From there, it automatically delivers the right lighting mode through any TUO bulb in your home — at precisely the right time, every day.

Most of us have 30 minutes of jet lag every single day

Most adult circadian rhythms run about 24.5 hours — not 24. Without proper light cues, we drift out of sync with our schedules every day. Scientists call this social jet lag: the gap between your biological clock and the social clock (school, work, obligations) that runs on a strict 24-hour cycle.

It's why alarm clocks exist. It's why teenagers sleep all the time, while grandparents are up at 5am. TUO's morning Wake mode corrects this drift daily — automatically.

Watch the science explained

University of Washington researchers explain the circadian light breakthrough — with 3D animations of cone-to-ganglion-cell pathways.