Out of the box, the bulb runs in Wake mode without Wi-Fi or the app. To change modes and run your personalized Circadian Plan, connect it to the free TUO app for iOS or Android.

A 2.4 GHz Wi-Fi network with a regular network name and password. The bulb can't connect to 5 GHz-only networks, or to networks that need a second login page, which are common in offices, hotels and coffee shops. Most home routers broadcast both 2.4 and 5 GHz; choose the 2.4 GHz network during setup.

Any standard US E26 lamp socket. Our shadeless lamp is designed for it, because shades can block or dim part of the light.

Don't use a dimmer switch. Like all smart bulbs, TUO runs on a microchip that partial power can damage. Keep any dimmer at 100 percent and dim in the TUO app or with Alexa.

TUO works with Amazon Alexa through the TUO skill, for on/off and brightness by voice. Sign in to Alexa with the same email you use in the TUO app. Google Home and Apple HomeKit are not supported yet.

TUO bulbs use the US E26 socket and 120V power, so they won't work in countries with E27 sockets or 220-240V power, even with a plug adapter.

About an hour of Wake mode soon after you wake up is typical. The TUO app's Circadian Plan sets the timing and duration from your age, chronotype and schedule. Treat its Wake recommendation as the minimum and adjust to how you feel. It can take 2 to 4 weeks of consistent mornings to notice the full effect, and the benefit lasts only as long as you keep using it.

Within about 6 feet (2 m), with TUO as the main light near you. Distance matters most in Wake mode. Several TUO bulbs in one space add up, so you can sit farther away. Most window glass blocks the violet light TUO relies on, so daylight through a window doesn't replace it.

No. Use it right after you wake up, whenever that is. If you work a later shift and wake at noon, use it then. Your body responds to light relative to your own schedule, not the clock.

Most people only need morning Wake light. In the evening, the Circadian Plan switches to Calm mode, which has no circadian effect. If you wake up hours earlier than you want, or get sleepy too early in the evening, Wake light in the 3 to 4 hours before bed can shift your clock later.

Not with TUO. Calm mode is a steady light that activates your eye's S-cones and L/M-cones equally so their signals cancel out, so you can use it at any brightness in the evening without affecting your body clock.

Use Wake mode in the morning and Active mode through the day. If you hit an afternoon slump, 15 to 20 minutes of Wake mode can help you feel more alert.

Start each morning with Wake mode, then use Active mode through the day. Short Wake sessions of about 15 minutes can help when you need a boost. TUO is designed to work at normal indoor brightness (around 250 lux), so it fits into your regular lighting rather than requiring a 10,000-lux light box.

About 2 hours of Wake light shifts your body clock by about 80 minutes, so plan on roughly 1.5 hours of Wake light for each hour of time difference. For example, a 3-hour time change takes about 4.5 hours of Wake light in total, spread over the days before and after your trip.

• Traveling east: use Wake mode in the morning soon after you wake up to shift your clock earlier.
• Traveling west: use Wake mode in the evening, in the 3 to 4 hours before bed, to shift your clock later.

Start a few days before you leave and continue after you arrive. For travel, our portable Fara light runs on a laptop power bank and works without Wi-Fi.

Yes. The bulb can display millions of colors, set manually in the TUO app. The Circadian Plan's Wake, Active and Calm modes adjust automatically through the day. You can also pick the color temperature you like for each mode: TUO is tuned to deliver the same circadian effect at every color temperature.

Circadian Impact Level sets the strength of TUO's circadian signal. Your Circadian Plan sets it from your age and chronotype, and you can raise or lower it in the app if the effect feels too strong, too weak or less comfortable.

Your chronotype is your natural sleep-wake tendency:

• Early Bird (about 28 percent of people): most productive in the morning, early to bed.
• Rooster (about 48 percent): balanced through the day.
• Night Owl (about 24 percent): most alert in the evening.

The Circadian Plan uses your chronotype and age to set how long Wake mode runs in the morning and when Calm mode starts in the evening.

Yes. Regular glasses are fine to wear while using TUO.

Your body clock reads the changing colors of dawn and dusk, not just brightness. TUO's patented light alternates between violet and orange to signal morning to the color-sensing cone cells in your retina, which relay that signal to the brain's master clock. The technology is licensed exclusively from the Jay Neitz Lab at the University of Washington School of Medicine. Learn more on our science page.

In a 2024 University of Washington study published in the Journal of Biological Rhythms, two hours of morning TUO light shifted the body clock earlier by about 1 hour 20 minutes, about twice the shift from blue light (about 40 minutes). Ordinary white light produced no measurable shift.

TUO emits no UV. Its circadian modes use little to no light in the 460 to 480 nm blue range that most circadian lamps and light boxes rely on. Instead, TUO uses the violet and orange color contrast of dawn and dusk, a good fit if you prefer to avoid blue-light-based lighting.

In Wake and Active modes, TUO alternates between two spectra that look the same color to your eye but stimulate your color-sensing cones differently. It alternates 19 times per second, the frequency at which S-cones responded most strongly in primate retina research at the University of Washington's Neitz Lab. Some people notice a subtle pulsing, especially when looking directly at the bulb or at higher Circadian Impact Levels. You can lower the level in the app for comfort. Calm mode is steady and does not alternate.

We recommend that people with epilepsy or photosensitive conditions do not use TUO's Wake and Active modes, which alternate spectra 19 times per second. Lowering the Circadian Impact Level reduces the pulsing but may not eliminate it. Calm mode is steady.

Tap rescan first; the first scan sometimes misses the bulb. Then check that:

• The TUO app is up to date and has Bluetooth and location permissions.
• You're on a 2.4 GHz network that doesn't need a second login page.
• Your phone is within 10 feet of the bulb.

If it still won't connect, factory reset the bulb (below) and add it again in the TUO app. Don't connect your phone directly to the TUO_Bulb_XXX Bluetooth signal.

1. Turn the bulb off and on 5 times within 8 to 10 seconds.
2. It will flash red. Leave it on and let it boot up. If you turn it off while it's flashing red, start over.
3. Add it in the TUO app as a new light.

A reset clears the bulb's Wi-Fi details, so use it when you change routers or networks too.

• Update to the latest version from the App Store or Google Play.
• Force close the app and reopen it.
• Check that Bluetooth, location and notification permissions are on.
• If problems continue, uninstall and reinstall the app.

Password rules: at least 8 characters, with an uppercase letter, a lowercase letter and a number, and no special characters. Still stuck? Email info@thetuolife.com with your phone model and OS version.

The TUO app notifies you when your phone's time and your account differ. Open the app menu, choose Sync Time and tap Sync.

Older firmware could cause this. Current firmware keeps the bulb in its last mode, including off, while it reconnects to Wi-Fi. Bulbs update automatically when they're online, so keep them connected. If it continues, email info@thetuolife.com.

A green or pink tint means one of the bulb's LED color channels has failed. For that, or a bulb that won't turn on, email info@thetuolife.com with your order number and a short description or video. Defective bulbs are covered by our 2-year warranty and most are replaced within 5 to 7 business days.

Recycle it like other LED bulbs. Many hardware stores have LED recycling bins.

We currently ship within the United States only. Shipping is free on orders of $100 or more, and $6.25 on smaller orders. Faster options and delivery estimates are shown at checkout.

If you're unhappy for any reason, return your purchase within 30 days for a full refund. No reason needed. Email info@thetuolife.com with your order number or proof of purchase to start a return, and keep the original packaging if you can.

If an item arrived damaged or isn't working, we'll email you a prepaid shipping label and replace it quickly. Approved refunds go back to your original payment method. See our full refund policy.

Having trouble with your light? Please reach out before returning it. Many setup issues take just a few minutes to fix, and we're happy to help.

Every TUO product includes a 2-year limited warranty covering defects in materials and workmanship when used as directed. Email info@thetuolife.com with your proof of purchase and we'll repair or replace it. Details are in our refund policy.