What is the best way to correct circadian rhythm if staying up 4 hours late working every night?

Melatonin. Melatonin can be taken to help correct the circadian rhythm. Also get up at the same time every morning even on weekends. Don't stay up late/sleep in late on weekends. You will have trouble on monday if you do. Avoid reading or watching tv in bed. Cut down or eliminate caffeine. If you are tired in the afternoon don't nap (or very brief nap only) then go to bed early (instead of napping).