Hypothyroidism can occur at any age, but is more frequent in the elderly, and it is estimated that up to 5 per cent. of people over 60 years of age are hypothyroid with an estimated market size for patients who do not respond to T4 replacement therapy alone (T4 non-responders) of $0.7 billion per annum worldwide.

Diurnal is developing a physiological combination therapy of the T3 and T4 hormones,Tri4Combi™, for patients suffering from hypothyroidism. Diurnal has completed initial formulation development to enable selection of a suitable technology to generate new formulations of the hormones T4 and T3, which will allow the replacement of the normal physiological ratio of T4 to T3 to be tested in the clinic. It is anticipated that this may address the need of approximately five to 10 per cent. of patients who have a poor quality of life on current thyroxine replacement therapy (Wiersinga 2014).

Article by W.M. Wiersinga entitled ‘Paradigm shifts in thyroid hormone replacement therapies for hypothyroidism’ published in Nature Reviews Endocrinology (2014) Mar; 10(3): 164-74.



No current products exist that replicate the natural physiological rhythm of T3 and physiological ratio of T4 to T3.