What supplement will help me out?

Hello, I am 17 years old and I am training for the Chicago marathon. I am a great runner but this summer I ate more than I usually do and now I have some fat on my body. I am considering taking a weight loss supplement. I am looking at taking either VPX Meltdown or Muscletech's Hydroxycut . But I don't know if there will mess with me while I am running.