Preparing for your Cortisol Blood Test

Cortisol levels follow a natural daily cycle, peaking in the early morning (around 6–8 AM) and gradually declining throughout the day. Because of this pattern, the timing of your cortisol test is important. For the most accurate results, take your sample between 6 AM and 10 AM. If you have an irregular sleep schedule, your results may be less reliable. If you need to test, do so within two hours of waking and include this detail on the lab request slip. You should also stop taking biotin supplements at least 72 hours before your test unless advised otherwise.

Please note that following the instructions step by step is crucial, as not following them may lead to sample rejection.