Depends on your schedule really. If you want to put it on before, wait a while, I kind of remember reading on Avants site like 2 hours, before exercising/sweating. If not, the cap will run downward - not a feeling you want. Also, if you are going to shower right after cardio, it would make more sense to wait to apply the lipo/cap until after you shower.
Have you tried the cap/lipo yet? I did a twice daily apllication, once after my morning cardio/shower and again before bed (minus the cap). It seemed to tighten up my midsection nicely. However, the cap really burns the first few times on, and continues to burn when you apply it to new areas.
Hope this helps.