Updated: Mar 19, 2022
While there is NO one perfect test to get completely accurate hormone level readings, a ton of scientific research has shown that saliva testing is the best way to accurately determine how if, when, and how much cortisol your body is making throughout the day.
Here are some of the other upsides to saliva testing:
It's convenient (you don't have to leave your home if you don't want to).
There are no needles involved, no blood draws, just spitting into tubes.
It's the only way to determine how much of the cortisol you do have is actually doing something (this is the fraction of cortisol that is actually 'biologically available' to do its job in the cells). Blood tests can only determine the total amount of cortisol, not the 'bioavailable' amount.
Cortisol is normally released in a specific pattern throughout a 24 hour period, something known as the "diurnal" pattern of cortisol release. Every single cell and tissue in your body relies on this normal pattern in order for them to work normally.
Under optimal conditions, cortisol levels should peak first thing in the morning and gradually declining as the day goes on. Collecting four saliva samples over the course of the day gives important information about how cortisol is being produced. Here's an example of what a normal pattern should look like:
If your salivary cortisol release pattern doesn't look similar to this, you probably have some issue with your stress response system. Now the key is to figure out what.