History

First used in the early 1890s, natural thyroid preparations, mostly DTE, were the standard treatment for hypothyroidism until the mid-1970s.

The earliest forms of natural thyroid came from the thyroid glands of cows, but early in the 1900s, the Armour meat company got into the thyroid medication arena, marketing its own natural desiccated thyroid from pigs, known as Armour Thyroid. All commercial DTE now comes from pig thyroids.

DTE contains both thyroxine (T4) and triiodothyronine (T3), as well as a hormone called calcitonin and other compounds. A normal human thyroid gland produces T4, T3, and calcitonin as well.

When synthetic T4 (levothyroxine) was first available in the 1950s, doctors were reluctant to prescribe it because they were afraid that since it didn't have T3 as DTE does, it might cause people to end up with T3 deficiencies. It was also considerably more expensive than DTE.

Around the same time, there were starting to be serious concerns about the potency of DTE. With a limited shelf life and major variability in the amount of active hormones found in the medication (it could contain anywhere from twice the amount needed to none at all), DTE began to get a bad reputation from which it hasn't totally recovered, despite the fact that in 1985, revised U.S. Pharmacopeia content standards made the potency stable.﻿﻿

In 1970, scientists discovered that T4 converts to T3, alleviating the previous worry that levothyroxine as a standalone treatment could lead to T3 deficiency. In addition, the specific lab test to check thyroid stimulating hormone (TSH) levels was developed in 1971, giving doctors a way to better monitor the effects of hormone replacement medication.

New awareness of T4's conversion to T3 and the advent of the TSH test sparked the trend toward increasing numbers of physicians prescribing levothyroxine as the sole treatment for hypothyroidism. By 1974, the treatment recommendations proclaimed levothyroxine "the agent of choice."﻿﻿

Despite the preference toward levothyroxine, DTE started to make a resurgence in the 1990s as interest in natural medicine increased. At that time, patients who weren't feeling well on levothyroxine were also becoming more empowered and aware of treatment options—like Armour Thyroid, Nature-Throid, and other desiccated thyroid drugs—thanks in part to the internet.