You know how you woke up this morning feeling exhausted even though you got 6-8 hours of sleep? It probably has something to do with you being glued to your smartphone sleep all the way up until your head hit the pillow – or even afterward! Our friend Science tells us that light on the blue end of the visible spectrum stimulates our brains and makes us think it’s daytime even when it’s not. Blue light makes us stimulated and ready for action. This was an awesome evolutionary trait back when the only time we saw the color blue was during broad daylight, but evolution selfishly decided not to take into consideration the fact that we would develop screens and stay up way past sunset chatting and browsing and endlessly scrolling. This is where f.lux comes in.

Previous coverage:

Sleep-aiding f.lux is coming to Android (root required)

February 20, 2016

F.lux lets you maintain your unhealthy day-night cycle without compromising quality sleep. The app, which has long been available for the computer, gradually alters your screen so that blue light is filtered out, leaving only calming reddish hues. It happens so gradually that, over a long period of active use, you probably won’t even notice it. Since people are spending more and more time on their smartphones toward the end of the day, it only makes sense that the app would make a splash on them. And so far, it looks pretty hot.

Since f.lux intercepts colors at the pixel level and filters out blues, it unfortunately needs root access to run correctly. If you’re a root user and would like to give it a try, f.lux has now officially opened up beta testing signups. There appears to be no limit to the number of people who can sign up, but the company is permitting groups of new signees to come into the program in waves. That means if you want to get your hands on this early version of f.lux, the sooner you sign up the better. Click the button below to head over to the beta landing page, and let us know your thoughts of f.lux in the comments below!


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  • Minioo

    Shame it’s coming so late. Night mode is coming in Android N anyways. Using it on my MBP and I love it :)

    • Andrei

      I wouldn’t call that late, Marshmallow it’s a few months old and barely has a 2% distribution. It’s sad that it requires root but I guess there’s no other way right now.

  • Adam Turransky

    When will the app be released for all users?

  • Mikhail Cass

    I have F.lux on my Latop. I’ve been using Twilight on Android.
    Does the same thing, free and Paid version.
    No ads in the free version and it doesn’t rewuire Root.
    Why is this better?

    • sdelfin

      F.lux actually changes the color temperature of the screen. Apps like Twilight apply a screen filter via software. I like Twilight and similar apps, but they have downsides. Twilight would randomly close often on my older phone blasting me with bright light at horrible times. Most people say that f.lux looks a lot better than Twilight when it’s applied. I have to agree with that. I’ve been using CF.lumen, which does the same thing as f.lux, for a while now and I prefer it. It’s worth trying for yourself if you have a rooted device.

      • Mikhail Cass

        Well I like using my phone/watch combo to pay for stuff so I can’t get root :/
        Guess I’ll stick with Twilight which has been great for me so far.

  • John Doe

    I have reading glasses that do this .. and I am already getting sleeeeppppppyyyy…………ZzZzzz zz zz Snore .. lol

  • Kevin Davis

    Maybe you could put, (root required),in the title of the article or at least somewhere near the start of the piece.

    • yankeesusa

      It’s in the article if you actually read it.

      • Kevin Davis

        I did read the The article,it might help if you actually read what I stated,as in,IN THE TITLE OR NEAR THE START OF THE ARTICLE.Hey,thanks very much though.

  • Johann von Schadowitz

    What is the difference to Twilight?

    • Yellow vs. Red tinting, and a root requirement. So unless you’re already rooted, stick with Twilight. There are also Windows & Mac versions of f.lux, so if you’re use to its color scheme on desktop, I guess it’d be nicer. ( I do use it, but Twilight works just fine anyway)

    • sdelfin

      Twilight is a software filter while f.lux actually changes the color of the screen. Twilight and similar apps have a hazy look compared to f.lux(and cf.lumen). Twilight is good, especially if you do not want to root as that has its downsides as well.

  • r1Gel

    My ASUS Zenfone2 has a bluelight filter mode built right in

  • Kevin Davis

    I did read the article,that is why I said in the title or at the beginning of the article.Of course you would know that if you actually read my comment and thought for just a moment how far down the body of the article the root requirement is listed.

  • sri charan

    Zenfone 2 has a kernel level built-in bluelight filter….but will install it on all my other phones….