Whole Thyroid For Improved Cognition and Mood

By Dr Gail Valentine


See Whole Thyroid For Improved Cognition and Mood - Page 1 - April 1999 for main article

Thyroid as Neurotransmitter?
Back on the track of the latest literature, research has suggested that thyroid hormone may, in fact, act as a neurotransmitter or as a molecule that helps transmit information in the brain and perhaps throughout the body.4 At the Veteran's Affairs Medical Center in Philadelphia, a recent study calls into question the definition of neurotransmitters. They argue that during brain development and before neurotransmission function has been entrenched, many neurotransmitters act as growth regulators. In other words, they act like hormones.

Yet even in the adult brain, when these neurotransmitters mature in their roles and adapt to memory requirements,  growth-related processes remain their continuing responsibility. Catecholamines, such as noradrenaline (the brain's version of adrenaline), demonstrate this type of behavior, and now evidence indicates that thyroid may similarly cross over in the adult brain and behave like a neurotransmitter.

The thyroid hormone T3 has been shown to be concentrated in the brain in noradrenergic centers (where there is noradrenaline) including the locus coeruleus (a control center of the brain). New structural data allows us, for the first time, to understand the thyroid hormone circuitry in the locus coeruleus (located at the base of the neck behind the cerebellum). High concentrations of noradrenaline in the locus coeruleus are now known to actively help convert thyroid hormone T4 to T3, leading to the preeminence of the locus coeruleus as a site of T3 concentration.

Brain Adrenaline-Thyroid Intimacy
The meaning of this study establishes that not only is thyroid hormone capable of operating as a neurotransmitter but that noradrenaline and thyroid hormone systems are interconnected. Thus, there exists a direct connection between these systems, supporting the idea that T4 or T3 may serve as co-transmitters with noradrenaline in the nervous system. Figuratively, this means that noradrenaline and thyroid share information and co-transmit. Thus, it is reasonable to conclude that supplementing one hormone or neurotransmitter may help the other. For example, supplementing thyroid may bolster the noradrenaline function and vice versa.


  1. Bunevicius R, Kazanavicius G, Zalinkevicius R, Prange AJ Jr. Effects of Thyroxine as Compared with Thyroxine plus Triiodothyronine in Patients with Hypothyroidism N Engl J Med. February 11, 1999;340(6):424-429.
  2. Visser TJ, Leonard JL, Kaplan MM, Larsen PR. Kinetic evidence suggesting two mechanisms for iodothyronine 5'-deiodination in rat cerebral cortex. Proc Natl Acad Sci 1982;79:5080-4.
  3. Pekary AE, Hershman JM, Sugawara M, Gieschen KI, Sogol PB, Reed AW, Pardridge WM, Walfish PG J. Preferential release of triiodothyronine: an intrathyroidal adaptation to reduced serum thyroxine in aging rats. Gerontol 1983 Nov;38(6):653-659.
  4. Dratman MB, Gordon JT. Thyroid hormones as neurotransmitters. Thyroid 1996 Dec;6(6):639-47.
© Copyright 1999 Life Enhancement Products, Inc. All Rights Reserved.

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