You have comparison up there- adrenal vs hypothyroidsm so you can check symptomse there, but when your adrenals are really underperforming- basically you feel bad- fatigue, sugar drops down all the time, fell shaky, brain fog, sleepy- especialy "mid day crisis", you even get feeling of euphoria sometimes; in the last stages you can barely move around, feeling completely weak and if not treated person may die.
Even if adrenal insufficiency is not so severe anyway- it will affect thyroid first and eventually testosterone will go down.
When it comes to hormones- adrenal insufficiency is worse than low thyroid output or low testosterone.
ACTH stimulation test will tell you how capable is your adrenal gland, and wheter problem is with adrenal glands capability of wheter problem is elsewhere (primary vs secondary), also to see what is actualy happaning in body you need to test actual hormones
Problem when testing adrenal hormones is that- aldosterone tests are inaccurate, patients are actually diagnosed as aldosterone defficient by symptoms, cortisol release is going by circadian rhytm which is different from person to person (depending on lifestyle) and you need to get 4Xtests (morning, afternoon, night...) to get picture- here salivary is good, urinary is also ok, blood tests are so-so
DHEA(s) tests seems to be reliable
and Progesterone tests are OK- so to confirm adrenal issues you would need 4X cortisol test and progesterone, and DHEA(s) optionaly and of course:
ACTH stimulation test - Wikipedia, the free encyclopedia
By the way pregnenolone is good in helping low-medium issues with adrenals, only thing is pregnenolone is quite volatile hormone and you never know where is going to end but generaly it does top up progesterone and if its going to top up cortisol, its always question
Personaly, when my adrenals were in really bad shape- pregnenolone gave me big lift, in other times I did not feel a thing from pregnenolone.