If you're sleeping between 7 to 10 hours a night and still cannot get rid of that tired feeling, it most likely has nothing to do with the amount of sleep. There are a few potential reasons for you to be feeling this way.
One of these is if you have anemia. There are several types of anemia, conditions in which there are low levels of erythrocytes and hemoglobin, which prevents the body from getting the necessary amount of oxygen. One of the common symptoms of anemia is the lack of energy and chronic fatigue.
If you have an inconsistent sleep schedule, you can try to get enough sleep on your days off but if you need to fall asleep and wake up at different times during the week, this disrupts your biological circadian rhythm, a key regulator of sleep.
You might be bored. The lack of stimulation can influence your energy levels. If you're bored at work, think of a new, more interesting project. You will see that an active mind can do wonders for your energy.
If you do not get enough sunlight. It sends signals to the brain that release serotonin, a natural chemical substance which makes a person feel happier and more wakeful.
If you drink too much coffee. It's difficult to give up coffee if you're lacking energy, but despite how awake you might feel, excess caffeine can have a negative influence on the quality of your sleep, which in turn leads you to reach for yet another cup of coffee.
If you're under stress. The hormones of stress - adrenaline and cortisol, constantly stimulate you but if your internal signaling system is working nonstop, you will start to feel tired.
Chronic stress drains people of their energy and hinders their ability to deal with dangers, either real or caused by the stress itself. Try to find out which one of the possible reasons is responsible for your state and try to eliminate it, before you seek any kind of artificial stimulants.