Korrus OIO Review: The Circadian Bulb Nobody Knows About

Here's a strange situation: the most technically advanced circadian light bulb on the market has almost zero online presence. No Wirecutter review. No YouTube unboxings. No Reddit threads. If you search "best circadian light bulb," you'll find TUO, Bon Charge, Hooga — but not OIO.

That's a problem, because after spending time with this product, we think it's the one most people should buy.

What Is OIO?

OIO is a smart circadian light bulb made by Korrus, a company that's been quietly working on the intersection of light and human biology for over a decade. Korrus isn't a Kickstarter wellness brand — they hold over 500 patents in LED spectral engineering and are the parent company of Soraa (co-founded by 2014 Nobel Prize winner Shuji Nakamura, who invented the blue LED) and EcoSense, a commercial lighting company that illuminates some of the most iconic architectural spaces in the world.

The pedigree here is unusually deep for a consumer light bulb.

The Science

OIO's approach starts with a fundamental insight that most "smart bulb" companies ignore: color temperature is not the same as spectral content.

When a Philips Hue dims to 2200K, it looks warm. Your eyes perceive amber. But the underlying spectral power distribution still contains blue wavelengths — the exact frequencies that activate your retinal ganglion cells (ipRGCs) and signal your brain's suprachiasmatic nucleus (SCN) to suppress melatonin.

OIO doesn't just shift color temperature. It engineers four distinct spectral recipes:

• MaxBlue (morning) — Enriched with sky-blue wavelengths (>20% blue content) to powerfully suppress melatonin and drive morning alertness. This is the "wake up" signal your biology expects from daylight.
• Daylight (midday) — Museum-quality, blue-rich balanced daylight. Clean, bright, excellent color rendering for focused work.
• ZeroBlue with Violet (evening) — This is where the magic happens. Blue wavelengths are removed, but violet is retained — giving you usable, comfortable working light that doesn't look like a campfire, while letting melatonin production begin.
• Deep Warm (night) — 1400K amber-red. Minimal circadian disruption for the last hour before sleep.

Setup & App Experience

Setup is straightforward:

1. Screw the bulb into any standard socket (A19 or BR30)
2. Download the OIO app (iOS or Android)
3. Scan the QR code on the bulb packaging
4. Connect to your 2.4GHz WiFi
5. Set your daily schedule (wake time, wind-down time, bedtime)

From there, it's fully automatic. The bulb transitions between its four spectral modes based on your schedule. No daily interaction required. This is the "set it and forget it" experience that manual-toggle bulbs like Bon Charge and Hooga simply can't deliver.

The app also supports:

• Room-by-room control and scheduling
• Manual overrides when you need them
• Integration with Matter, Apple Home, Google Home, and Amazon Alexa

The Matter support is worth highlighting. Matter is the new universal smart home standard, and OIO is one of the first circadian bulbs to support it. This means it works natively in Apple Home automations, Google routines, and Alexa scenes without relying solely on the OIO app.

The OIO Loop: See What You Can't See

One of the most clever additions to the OIO ecosystem is the OIO Loop — a small handheld optical scope that lets you see the light spectrum as a visible rainbow.

Hold it up to any light source and you'll see exactly which wavelengths are being emitted. Point it at a standard LED at night and you'll see a bright blue spike. Point it at OIO in evening mode and the blue band disappears.

It's part educational tool, part proof-of-concept. Once you've seen the blue spike in your current bulbs, you can't unsee it. You understand viscerally why standard LEDs at night are a problem — and why OIO's spectral engineering is different from just dimming to a warm color temperature.

The Loop comes included with the OIO Sphere ($149.99), or may be available separately.

Hardware Specs

800 lumens at 9W is solid. For context, TUO markets 600 lumens but testing by OptimizeYourBiology measured only 355. OIO's 800 lumens is standard for a 60W-equivalent LED, so you're not sacrificing brightness.

Pricing

At $30–35 per bulb (A19, 10-pack), OIO is premium but not unreasonable. For reference:

• TUO costs $53–59/bulb — nearly double
• Bon Charge is $35/bulb with no automation
• A Philips Hue setup (bulbs + Bridge) runs $25–30/bulb with inferior circadian function

What We'd Improve

No product is perfect. Here's what we'd like to see:

• Dimmer switch compatibility. OIO doesn't work with dimmer switches. If your home has dimmers on every circuit (many newer homes do), you'll need to swap them for standard switches or use smart dimmers that pass full power.
• Amazon availability. Right now, OIO is only sold direct through korrus.com. That limits discovery and makes it harder for people to stumble onto the product. Amazon distribution would be a game-changer for awareness.
• More visible reviews and third-party testing. The product is excellent, but the lack of mainstream coverage makes it a harder sell to skeptical buyers.
• 5GHz WiFi support. The 2.4GHz-only requirement is standard for smart bulbs but can cause setup friction in homes where 2.4GHz is disabled or poorly configured.

Who Is This For?

• Anyone serious about sleep quality — if you've tried melatonin supplements, blue-blocking glasses, or sleep tracking, circadian lighting is the next logical step. It addresses the root cause (your light environment) rather than treating symptoms.
• Biohackers and health optimizers — if you follow Huberman, Attia, or Asprey, you already know light matters. OIO is the most science-backed way to fix your home lighting.
• Smart home users — Matter support means it integrates cleanly into existing Apple Home, Google, or Alexa setups.
• Parents — evening blue light is especially disruptive to children's sleep. Automating the light shift means you don't have to remember to change it.
• Remote workers — getting proper blue-rich light during the day and removing it at night is especially important when you're indoors for 10+ hours.

The Bottom Line

Keep Reading

• Best Circadian Light Bulbs (2026): Full Comparison
• TUO vs OIO: Head-to-Head
• OIO vs Philips Hue
• How to Set Up Circadian Lighting in Your Home
• How Light Affects Your Sleep (The Science)
• Home Office Lighting for Focus and Better Sleep
• Best Lighting for a Baby Nursery
• Circadian Lighting for Shift Workers