Dysfunction within the HPA axis (which involves 3 distinct organs) can be a little complicated and you're probably better off testing for specific info so you have a better idea of what levels to target. Naturopaths are your best bet - endocrinologists generally don't have this training, although are helpful if you should have, say, thyroid cancer.
The HPA are also interconnected - it's your pituitary that generates signals to the thyroid to produce thyroid hormones that are required for numerous functions throughout the body. Neurotransmitters are also using associated chemicals and hormones to function normally.
A 24-hr saliva test can help you understand how your adrenals and neurotransmitters are functioning (incl. cortisol) and I would also ask for a thorough thyroid work up, which includes T4, T3, Reverse T4 & T3 and Free T4 and T3. You'll also get TSH by default but make sure that isn't the only level that is checked. TSH is the hormone produced by the pituitary that signals the thyroid to produce the other T4 & T3 versionS. www.healingwell.com/community/default.aspx?f=30&m=3665057&g=3665506#m3665506
There are other specific tests for pituitary, should results start leaning toward pituitary dysfunction but most of them have clear symptoms.
There are multiple forms of B12 due to methylation issues people have. So you'll see cyanicobalamin (synthetic), hydroxocobalamin, methylcobalamin, etc. that are basically B12 broken down into simpler versions for the body to metabolize. you can do a search for other conversations about
B12 versions. Without knowing what your specific methylation issues might be, you might need to test out different versions to see what works best for you.
Hope this is helpful -
Chronic late-stage lyme—likely infected in 2000; Clinically dx Mar'14 w/ Babs, + for Bart, CDC + for Bb. Multiple viruses & GI/immune treated first; started AL-Complex in May, A-Bart & A-Bab in July; Nov'14 IV port installed-started Rocephin; added vancomycin Mar'16
DETOX: Pinella/Burbur/Parsley/Milk thistle/Burdock root; cholestyramine / jap. knotweed L-5-MTHFR LMN-V-II probiotic