Got any patients on Natural Thyroid Extracts (NTE)? Me too…and I am finding it’s on the increase. What’s the deal? What do we need to understand about this form of thyroid replacement therapy to best monitor and manage those patients already on it or contemplating taking it? Does it really offer advantages to all hypothyroid patients or just to a subset of those and how would we recognise these people who might benefit the most?
NTE are marketed as being superior to synthetic thyroxine primarily based on the fact that they provide the patient with some T3 as well as T4 and in addition to that, being extracts of pig thyroid glands, there are other thyroid and iodine based actives e.g. mono and diiodotyrosine, present in the extracts. So in essence this is giving us more iodine and more of the other ingredients we need to make our own thyroid hormones. Based on this, many proponents of NTE say this is a major advantage over synthetic thyroxine replacement because it is more ‘holistic’ and it supports the patient’s gland in its own hormonogenesis.
Hmmmmmmmmmmm…yes but no but maybe.
Often the doses used of NTE provide enough fully formed thyroid hormone to be equivalent to thyroxine and therefore remove the need for the gland to produce thyroid hormones itself. I am not saying the mechanism is not different and doesn’t have some potential advantages but I do think to suggest taking NTE is NOT thyroid replacement is a bit misleading.
It may surprise some of you that NTE were of course the original medical treatment for hypothyroidism and were heavily prescribed from the late 1800s all the way through til the 1950s when thyroxine was developed by a pharmaceutical company. But far from being a thing of the past, evidence suggests that in the US, NTE are use by 50% of patients requiring thyroid replacement (that’s about 8 million individuals!!) The rate of NTE use there is markedly higher than here, in part because of a stronger tradition among doctors but also because of course naturopaths in the States are able to prescribe these as well.
The American Thyroid Association & the Endocrine Societies both here and overseas discourage the use of NTE based on a range of concerns including that NTE are not produced by pharmaceutical companies, not as tightly regulated (though they are approved by the FDA) and therefore purity, potency and stability remain in question. I think some of these concerns are valid , particularly if practitioners are not discerning regarding source and reputation/track record of the NTE manufacturer. These authorities also claim insufficient evidence to support safety and efficacy of NTE. Studies looking at NTE or T4/T3 combinations have been done since the 1970s, however, the methodologies used etc have lead to limited generalisation.
A relatively new study published in 2013 by Hoang et al. helps to add to our NTE knowledge base, particularly with respect to the most well known and widely used NTE Armour Thyroid. This study of just 70 individuals treated with either Armour Thyroid or Thyroxine in a double blind manner did not demonstrate an irrefutable advantage of one over the other but it did produce some interesting points of differences in clinical outcomes (improved cognitive outcomes and weight loss in patients taking Armour Thyroid over thyroxine) and patient preferences (Spoiler alert!….Armour won). Definitely worth a read.
But before anyone gets too excited about NTE you need to remember that it is ultimately a replacement approach and, as always, we need to be certain that we have done all that we can to identify and treat the cause before we jump to replacement. In particular there is a long list of differentials to explore in the ‘low T3’ patients at whom NTE are particular targeted. There are also legitimate concerns about quality and purity etc as mentioned above.
I’ve enjoyed getting to know a whole lot more about NTE and thyroxine replacement over the last month – it helps to build my understanding around interpreting the sometimes unusual TFTs you get from patients taking either and around improved patient care of these clients. I’ve just recorded an Update in Under 30 on this topic, summarising all the scientific reading, learning from prescribers and my own experience with patients on various thyroid replacement strategies…for your listening pleasure 😉
‘Thyroid replacement – Thyroxine V Natural Thyroid Extracts’ is the latest installment in our dynamic Update in Under 30 series. This punchy podcast highlights the points of difference in the two approaches, the strengths and limitations of each, with lots of surprises along the way! From more documented stability issues with the synthetic form to inconsistency of potency in NTE. Getting to know these two approaches will help you both to identify which path might be preferable in your clients in need of replacement as well as being better equipped to monitor, manage and mediate when the strategy fails to hit the mark.