Goitres are associated with a variety of conditions such as iodine deficiency, hyperthyroidism, hypothyroidism, inflammation, and autoimmune disorders. In most cases, treatment revolves around restoring thyroid function, with less emphasis on resolving the goitre. Hence, be it for cosmetic or medical concerns, many patients with goitres have turned to traditional Chinese medicine (TCM). Many herbs used in the management of goitres contain iodine in varying concentrations. A single case report presented by Karsten Mussigg et. al (2006) highlighted the need to evaluate the use of iodine-rich herbs in treating thyroid disorders after it was discovered a patient taking Haizaoyuhutang (海藻玉壶汤) developed iodine-induced thyrotoxicosis which resolved after stopping TCM herbal treatment and receiving antithyroid drug therapy.

Traditional Chinese medicine believes that goitres are due to stagnation of phlegm and Qi, which progresses to form a solid mass. Therefore, herbs that regulate Qi, disperse phlegm, and resolve solid masses are employed accordingly for treatment. Of which, Sargassum pallidum (海藻), Thallus laminariae/Thallus eckloniae (昆布), Spica prunellae (夏枯草), Concha ostreae (牡蛎) and Fritillaria thunbergii (浙贝母) are traditionally used and proven to be effective after centuries of clinical practice. The iodine content of popular herbs back then are summarised in the table below:

Table 1 Practical Chinese and Western Medicine Thyroid Diseases or《实用中西医甲状腺病学》 by Gao Tian Shu (高天舒)

However, Liu (2019) found that in recent years the common herbs used in thyroid related conditions, in order of popularity, are Spica prunellae (夏枯草), Concha ostreae (牡蛎), Fritillaria thunbergii (浙贝母), Scrophularia ningpoensis (玄参), Angelica sinensis (当归), Paeoniae alba (白芍), Sargassum pallidum (海藻), Poria cocos (茯苓), Bupleurum chinense/Bupleurum scorzonerifolium (柴胡), Rehmannia glutinosa (生地). While the reason for the change in herb usage patterns is unclear, many researchers summarising TCM diagnosis and treatment methodology of thyroid conditions agree that there are currently four major schools of thought.

1. The first believes in keeping with tradition and advocates the use of iodine-containing herbs and established formulas, believing that their proven clinical efficacy in the past is a good basis for continual usage even in the modern times.
2. The second is in line with western practice in this aspect, completely rejecting the use of iodine-rich herbs, unless patients show clear evidence of iodine deficiency as they believe that iodine content in herbs is not regulated and can easily exceed the recommended daily intake requirement.
3. The third point of view promotes the use of herbs with lower iodine content, which allows traditional Chinese medicine practitioners to prescribe herbs according to traditional principles while minimising the risk of iodine poisoning.
4. The last group adheres to the fundamental basis of traditional Chinese medicine and upholds the importance of syndrome differentiation. From their perspective, in the cases of patients presenting with symptoms that indicate the traditional aetiology of phlegm and Qi stagnation, appropriate herbs backed with logical reasoning can be prescribed regardless of iodine content.

Most of the published trials we examined followed the fourth school of thought, treating the various thyroid disorders according to syndrome differentiation, and using iodine-containing herbs as needed. Although the quality of papers available were generally low (no blinding/placebo was used, and in many cases reporting of adverse effects or drop outs were not well elucidated), our literature review indicates an overall therapeutic effect in terms of restoring thyroid hormone levels. As compared to patients on conventional western medication alone, most patients who took TCM as well also had a more significant decrease in size of their goitres. However, it is important to note that a number of clinical trials that measured thyroid hormone levels have reported an increase in T4 levels, although they were still within the normal range. Most of such research had a limited treatment duration of 3 months. As we are unable to determine the long-term effect of prolonged iodine-rich herb usage, we would hence strongly recommend regular monitoring of thyroid function for patients consuming such products, and to ensure consistent follow-up with a licensed TCM practitioner.

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