Adrenal extracts are made from the adrenal glands of cows, pigs, or other
animals. According to a theory prevalent
in alternative medicine, the consumption of adrenal extracts can strengthen the function of an underperforming or exhausted adrenal gland. However, there is no scientific evidence to support this belief, and no rational justification to indicate that it might be true.
Early in the twentieth century, physicians used glandular extracts as an actual source of hormones.