Most supplements focus on things that will give you short term bursts of energy but will quickly fade and leave you drained. For sustained energy, you need proteins and carbs, beware of consuming too much sugar and caffeine. Also, don't forget that your muscles need calcium and potassium to function properly and avoid cramping after a ton of exercise (if you over-do it)
you can use USANA products :) proven effective and no side effects ever!
My best friend were now taking a supplement called MX Natural Energy. According to my best friend, it is a unique supplement that can boost one's energy and help one's better deal with stress in daily life. He said it works on him, i think i will give a try for this supplement. :)
Lots of supplements give energy...but let you down with a bang in the end. Sugar and caffeine help to deplete energy especially in excessive amounts. I think the best thing you can do is learn to eat healthy and exercise. Clean water, healthy eating / lifestyle fresh air and exercise works best. Don't exhaust yourself from burning the candle at both ends (it happens at times to the best of us). For me an instant energizer is running, yoga and pilates. Also check and make sure that low iron is not to blame or any underlying health issues.
I suffer from really intense fatigue so I've tried lots of things. The only thing that has ever really worked for me is a Omega 3 product called Omega Brite. It's nothin' fancy, just all those good Omega 3 fish oil supplements, but the delivery system it uses seems extra potent and it's the only one I've used that doesn't hurt my stomach. I also use a light box to give me energy and fight fatigue. Not a supplement, but I highly recommend it.