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Optimize Thyroid – Adrenal Cross-talk

Last week we talked about how chronic stress and cortisol wears out the adrenals, and how tired adrenals affect thyroid function. But there’s actually more to the story. Did you know that not only is thyroid hormone activity regulated in part by stress hormone activity, but the reverse is also true. The two hormonal systems interact throughout your body, in different tissues. Thyroid hormone sets a kind of “baseline” activity level and stress hormones, secreted from your adrenal glands, speed it up or slow it down.

The interaction is complicated and affects body heat, blood flow, heart rate, blood pressure and exercise tolerance. When thyroid hormone activity is low, the body has less freedom to adapt to its environment. On the other hand, high levels of stress hormones called catecholamines (epinephrine and norepinephrine)—can affect the conversion of T4, the inactive form of thyroid hormone, to T3, the active form.

The bottom line is: both hormone systems need to be functioning properly for either to work optimally. If one is out of whack, it will affect the other.

If these systems are out of whack, you may have a list of seemingly contrary symptoms — you may be tired but jumpy and have trouble sleeping, you may be sweaty and cold, but intolerant of heat. You may be depressed and anxious. You may feel light-headed when you stand up or try to exercise. You may have trouble concentrating and remembering things. You may be overweight but always hungry.

The fact that the thyroid and adrenal systems affect one another can also work for you. Sometimes the solution can be remarkably simple because correcting thyroid function can often correct adrenal function, and vice versa.The key to success is to pay attention to both.

Check your body temperature. (For instructions on how to do this correctly, see “How are body temperatures measured” on our website.) If your body temperature is consistently low—below 98.5 F., or 36.94 C, but typically lower than 97.8 F, or 36.56 C.— there’s a good chance that you have low thyroid hormone function. You may have this despite having normal Thyroid Stimulating Hormone (TSH) blood levels and even if you are taking what seems to be an adequate dose of T4 (Synthroid or levothyroxine.) In fact, high levels of T4 can inhibit T4 to T3 conversion. This is normally a protective feedback loop, but it can backfire when you’re already having trouble generating enough T3.

I’ve found that people with low body temperature can often improve dramatically if they get supplemental thyroid hormone in the form of T3. Normalizing body temperature with T3 can improve mood, energy level, ability to drop excess weight, and a host of physical symptoms. It can help your adrenal gland function better, too.

I’ve also found that people who have symptoms of adrenal fatigue, such as fatigue, especially in the morning, disrupted sleep, body aches, low blood pressure, light-headedness, salt and sugar cravings, brain fog, and trouble recovering from stress, can often improve on their own with lifestyle changes that include taking adaptogenic herbs. These herbs have a long and safe history of use for supporting energy and restoring calm focus in the face of stress. They include Holy Basil, Rhodiola, licorice, ashwaganha, Eleuthero root, astragalus, and others. You can read more about ashwagandha here and other adaptogens here.

If you think you might benefit from these therapies, share this article with your doctor, who can call us at 800.420.5801 to get more information about how to use T3, along with herbs to support thyroid and adrenal health, and to discuss your individual case. You can also use our website to find the health care practitioner closest to you who is trained in T3 treatment.

Of course, reducing stress as best you can and making sure you are getting the nutrients that support both thyroid and adrenal function (iodine, selenium, vitamin C, zinc, and more) are also important.


Silva JE, Bianco SD. Thyroid-adrenergic interactions: physiological and clinical
implications. Thyroid. 2008 Feb;18(2):157-65.

Panossian, A., et al. 2009. Adaptogens exert a stress-protective effect by
modulation of expression of molecular chaperones. Phytomedicine, 16 (6–7),

Yamamoto T. History of stress-related health changes: a cue to pursue a
diagnosis of latent primary adrenal insufficiency. Intern Med. 2014;53(3):183-8.

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