I'm an athete I workout and train 5 days a week. I smoked less that 0.5 of weed, how long will it take to get out m system ps im 23?

3 weeks or more. Depends how much you use it stays 3 weeks or more depends on use also intake of fluids and kidney filtration.
.5/day or just once? If you have been doing .5/day for a long time, it may take several weeks to clear, but if you only did .5 once, it may not even be detectable. Obviously you are concerned about the consequence of using it and i would suggest remaining weed-free. You r an athlete--u train because u want a healthy body, why bother using such? Stay healthy and be good, member73466! good luck.