Adrenal cortex is good for the adrenals. Also ashwagandha for the adrenals and would be a second choice. Diabetes is caused by hypopancreatic function along with weak adrenal glands.
pancreas needs zinc, Magnesium, chromium, vanadium to process insulin.
If there are heavy metals involved the endocrine system won't work well including the pancreas. Cleanse metals and the pancreas will work better.
Also if the adrenals fatigue the thyroid goes into hypofunction as well.