Savella (milnacipran) is proven. Savella, (milnacipran) one of the fda approved fibromyalgia treatments, has been shown in research to improve cognitive function as well as fatigue. However, it doesn't work for everyone. Stimulants medicines, like ritalin, are often used if patients fail savella (milnacipran). If you sleep is poor, improving your sleep quality can also help. If you are overweight, snore and tired during the day you might have sleep apnea.
Exercise! You are not alone; many of us experience "brain fog!" I have found that the best solution is exercise. Even just 5 minutes of lifting free weights in your living room or doing situps can help. Crank up your favorite music for motivation! often when we are tired/sluggish our brains are saying we need to increase activity, not to rest more as many believe.
Glutamine. L-glutamine removes brain fog take 1gm three times a day.