The reason Phosphodydle serine doesn't work sometimes is because it was taken orally. Absorbtion is very limited that way. I.V. works, but is expensive and impractical. IMO, the most practical way is either transdermal application (e.g. Apex Labs' AdrenaCalm) or orally as phosphorylized serine.
These would be used to LOWER cortisol at specific times of the daily cyle.
Another approach or tool would be a suppliment to boost cortisol at abnormally low times of the cycle (like in the morning), but without taxing the addrenals, and let the addrenals rest and rebuild. This is often seen in Adrenal Exhaustion. A good transdermal product to use here is also by Apex and is called Adrena-Stim. This is often used with liquid, sublingual, low dose prednisone for the first 30 days.
You've got to understand, before you can balance other endocrine disorders (including thyroid) you must first balance digestion and adrenals, and concurrently employ a life style change which includes both diet and stress reduction. Without these, everything else is an exercise in futility. One additional step would be to find out about one's food sensitivities (not necessarily allergies)
and reduce exposure to these.
IMHO, this is the key to any natural cure. E J