I used to feel that it was quite simplistic to think that eating an animal’s glands would help strengthen my own like glands. Along with many other medical doctors, I also think we should be able to measure the hormone activity of many substances and monitor its effect in the body. The glandulars are usually measured by the amount of the actual glands present, but we do not really know what they do. Further, since these glands are broken down into their basic nutrients in the digestive tract, they would not necessarily go directly to improve my own glands. Previously, I was a strict vegetarian, so for that reason alone I did not want to consume animal glands, which might also have a buildup of toxins or chemicals.

Now I feel more open to the possibility that glandulars have some use in supporting and strengthening specific organ function. On the positive side, it is likely that the basic components of those gland tissues may offer the precursor substances that our own bodies and glands can use to enhance their functions. And there may be hidden factors that may offer some benefit. The glands, like foods, supply basic nutrients, such as amino acids, oils, vitamins, other active ingredients, and a potential "life force," where a drug will not. Some evidence from radioisotope studies suggests that glands, when eaten, do in fact get to the human glands and influence them.

In modern medicine, glandular therapy with the use of whole glands began in the late nineteenth century when doctors suggested that their patients eat the animal parts, usually from cows, that corresponded to the weak areas of their own bodies. So people began eating brains, hearts, kidneys, and so on as part of their medical treatment. Actually, the ancient Greeks and Egyptians used glandular therapy, following their basic premise that "like heals like." Technology and medical endocrinology evolved this therapy by isolating specific hormones at the source of the glands’ activities (just as we extracted the active pharmaceutical drugs from whole plants). These new drugs are more potent, but they also have more potential for dangerous side effects than the whole glands.

For example, desiccated thyroid gland was first used in the late 1800s to help people with goiter and low thyroid function. Then thyroxine (T4) was isolated and used, but many doctors still preferred the whole gland as it was felt to be better absorbed and utilized. Later, the other thyroid hormones, triiodothyronine (T3) and calcitonin were discovered, but these were always part of the whole gland. Today, both individual synthetic hormones and measured active thyroid tissue are used to support or replace thyroid activity.