When Should I Apply?
As soon as you know you need the medication. WFDF asks for applications at least 90 days before you plan to use it or before your next competition. For substances prohibited In-Competition only, the absolute minimum is 30 days before your next competition, unless it's an emergency or exceptional situation.
A TUE only takes effect on the date it's granted. A pending application gives you no protection. You can apply retroactively (after using the medication) only if you needed emergency or urgent treatment, there wasn't enough time or another exceptional circumstance stopped you applying first, you were tested while below National-Level, or you used a substance banned only In-Competition while out of competition (a corticosteroid tablet weeks before an event, for example). Being eligible to apply retroactively doesn't mean you'll be approved.