Hyperthyroidism (also called thyrotoxicosis) is one of the most common diseases of the middle-aged and older cat. It effects many systems of the body caused by an increase in the amount of thyroid hormones (T3 and T4) produced by an enlarged thyroid gland. It was first documented in cats almost 30 years ago but the cause of the disease has been elusive. Although the enlargement in the thyroid gland is caused by a tumour called an adenoma, it is non-cancerous.

The most common clinical signs of hyperthyroidism in cats include weight loss, increased appetite (although some cats have depression and decreased appetite), vomiting, increased thirst and urination, hyperactivity, and diarrhoea. The high levels of thyroid hormones can cause the development of heart disease, and these patients may have a heart murmur, difficulty breathing, high heart rate and arrhythmias.

The herbs I include in my Thyroid Regulator mix are: Cactus, Hawthorn, Bugleweed, Scullcap, Maritime Pine Bark, Blue Flag, Dandelion