Is F.lux Safe for Computer?

✓ Medically Reviewed by Jack Cincotta


F.lux is safe to use on your computer but the efficacy of this application at blocking blue light must be examined further.

Harmful blue light can lead to digital eyestrain, computer vision syndrome and disrupt your sleep.

Computer screens emit blue light which can lead to digital eye strain. F.lux and other applications have been created to help tackle the issue of damaging blue light.

How does F.lux work?

F.lux is a piece of software that you can download for your computer or laptop. F.lux works by changing the amount of blue light that is emitted from your screens throughout the day.

Like all human beings you have evolved under the sun and developed circadian rhythms. F.lux attempts to match the amount of light emitted from the sun throughout the day.

You can manually set the amount of blue light emitted from your screen by using F.lux. This can be done safely whilst using your computer.

Pros and Cons or F.lux

Like any piece of software or product there are always pros and cons and these need to be addressed so you can make an informed decision of whether F.lux is for you or not.


  • Cheap to use
  • Easy to install
  • Filters down blue light and reduces color temperature



  • Does not block blue light
  • Does not eradicate flicker
  • Still leads to poor sleep


F.lux is cheap to purchase and relatively easy to install on your computer. The application filters down the level of blue light emitted by your computer.

F.lux does not block 100% of blue light. An application cannot completely solve a hardware problem. If you are looking to improve your quality of sleep by using F.lux it won’t work. You need to block 100% of blue and green light between 400nm and 550nm after sunset to significantly improve your sleep.

Flicker is also concern as well. LED back lit light sources flicker as they run off an alternating current. F.lux does not block flicking LEDs which indicates that using the application wont fully reduce symptoms of digital eye strain, which is influenced by flicker.

Other Popular Apps

There are other blue light filter apps that can manage blue light emitted from your computer. These are all just as safe as using F.lux.

You can use Iris software which works in a similar way to F.lux by rescuing blue light from your screen display.

Night shift mode on your computer and smart phone are already installed apps. You can toggle blue light up and down on this application to get your desired level of illumination. Night shift mode is essentially the same as F.lux in that is does not block all blue light. Learn more about how to turn blue light off on your computer here.

Apps like F.lux, Iris and Night Shift Mode are very useful during the day to reduce blue light exposure and protect your eyes, but may help only partially after sunset.

Proven Methods to Block Blue Light

If you want to block 100% of blue light there are a few ways you can do this that are most effective than using F.lux.

Purchase a pair of blue light blocking glasses that come with a red or dark amber lens coating. Blue light glasses that block 100% of blue and green light between 400nm and 550nm are optimal for improving your sleep and help you fall asleep faster.

Turn your smart phone screen red to totally eliminate blue and green light. I have personally spectrum tested this biohack and it works by blocking 100% of blue light

Installing red light bulbs in your house is another great way to limit blue light exposure rather than using regular lighting at night. Just ensure the bulbs you choose emit 100% red light.

Final Thoughts

F.lux is a great app to use at the right time of day. It will not help you block blue light after sunset. F.lux is safe to use on your computer and works well when combined with blue light blocking glasses, red light bulbs and other biohacking tricks.

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