In recent years, it became in vogue for thyroid patients to request supplementation with a combination of T3 (Cytomel) and T4 (levothyroxine sodium). Certain books and articles about T3 supplementation reported that it helped with "brain fog," depression, and other apparent symptoms of hypothyroidism. There was also a trend that began in psychiatry, where T3 was added to antidepressants, which reportedly helped alleviate depression, but which has been disputed by most endocrinologists as not helpful and potentially harmful.
A small pilot study on T3 supplementation was done in Kaunas, Lithuania, which involved 33 participants. Published in the February 11, 1999, issue of the New England Journal of Medicine, it reported that participants felt better and performed better according to their scores on standardized psychological tests. The small study suggested that a combination of T3 and T4 improved results of various psychological tests that assessed concentration and depression in hypothyroid patients. Unfortunately, the study was wrongly interpreted to verify that T3 supplementation improved quality of life for all hypothyroid patients. In my (Sara's) revised thyroid books from that period (1999 to 2002), I enthusiastically informed readers of this study, encouraged them to discuss it with their doctors if they thought they might benefit, but also expressed concerns over the potential risks as there were many groups of patients who might not be good candidates for T3 supplementation.
Since then, larger, well-designed clinical trials, published in 2003, investigating whether the T3/T4 combination offers any benefit to hypothyroid patients, failed to verify that there is any value in the combination T3/T4 therapy. In addition, a post-analysis of the 1999 study revealed many flaws in its design and interpretation. For example, half of the participants were thyroid cancer patients and not representative of the majority of people with hypothyroidism because they were on TSH suppression doses of T4, which sometimes create other problems. The reality is that many patient advocates were too quick to embrace the study as the solution for the hypothyroid masses.
From an ethics perspective, the mass dispensing of T3/T4 combination therapy is fraught with problems, since the risk of thyrotoxicosis (see next chapter) with T3 hormone is not insignificant. This can occur even under careful monitoring—something that is hard to enforce in a climate with fewer and fewer endocrinologists in practice, and overloaded primary care physicians.
What preceded these studies was an explosion of interest in T3 supplementation, and many doctors (some with questionable training in thyroid disease) began patients on T3. Doctors, who anecdotally reported improvement with T3 in patients with depression or other features of mild hypothyroidism, were actually reporting improvement when treating subclinical hypothyroidism itself rather than observing that T3 conferred particular benefits over T4. These patients had never been on the appropriate dosages of T4 to make their TSH levels normal in the first place.
Although there are rare endocrinologists who use T3 without T4, as a treatment for depression or other symptoms of mild hypothyroidism in the presence of normal TSH levels, this is not considered a standard of care that makes sense in light of the most current physiology knowledge and research. We devote more discussion to the use of T3 therapy in Chapter 10, which covers thyroid hormone in more detail. What's important to understand here is that top thyroidologists do not support the routine use of T3 in treating hypothyroidism—not because they do not have an open mind but because it doesn't seem to offer benefit and may offer some risks.
Thyroid patient advocates and thyroid patients on Internet listservs continue to cling to the T3/T4 combination therapy as the answer to living well with hypothy-roidism, while doctors who don't agree with this approach are labeled "closed minded" or too conventional. The only patients who should be on the T3/T4 combination therapy are those patients who have just had a withdrawal scan that checks for thyroid cancer recurrence and are temporarily climbing back up to normal levels of thyroid hormone, discussed more in Chapters 2 and 9. There may be rare cases in people who are severely hypothyroid who may be started on T3 until enough T4 builds up in their system, or T3 may be used in treating thyroid hormone resistance (see Chapter 18), but these situations do not represent the majority of hypothyroid people.
As of this writing, anyone that suggests to you that T3 should be routinely added to your T4, other medications you might be taking, or as a solo therapy, is not up to date.
Was this article helpful?
Are You Depressed? Heard the horror stories about anti-depressants and how they can just make things worse? Are you sick of being over medicated, glazed over and too fat from taking too many happy pills? Do you hate the dry mouth, the mania and mood swings and sleep disturbances that can come with taking a prescribed mood elevator?