Do we use only 10% of our brain?

So guys like title state do you believe that we only use 10% of our brain? (Myth) c:

No, science has already proven this false, as it says we use all of our brain at some point.

Nope. We use 100% of it, but not always simultaneously (due to its incredible resource requirements). This is completely supported by fMRI (functional magentic resonance imaging) among other methods which demonstrate brain usage, many animal studies including studies done on humans, and evolutionary common sense: the brain is the body's most intricate, highly-protected and energy-hungry organ. Using only 10% of it despite its extraordinary energy demands and intricacy is evolutionary suicide.

The brain is always in use, although maybe not 100% of the time. However, it is for certain that more than 10% of it is in use at any given time, even when you're asleep.

sometimes i feel like only 10% of it is being used...

this has already been proven false. the real question is what if, energy requirements and other considerations aside, we can use 100% of our brain all the time?