It really, really varies, person to person, optimized time vs non-optimized time. With keto plus several other optimizations, I'm sometimes good (focused, motivated, energized) for over 12 hours. Alternatively, I can have days where I never reach "good" at all.
For reference, I'm in my late 60's, and I don't inject anything. I've had a wide range of life-long health issues, but partly because I've optimized to be acceptably focused and productive while living with those issues (that I've been resolving one-by-one), I can have some pretty long periods of focus.
For reference, I'm in my late 60's, and I don't inject anything. I've had a wide range of life-long health issues, but partly because I've optimized to be acceptably focused and productive while living with those issues (that I've been resolving one-by-one), I can have some pretty long periods of focus.