Thyroid

Ashwagandha

Withania somnifera

In a trial of 50 people with subclinical hypothyroidism, 8 weeks of root extract raised T3 and T4 and lowered TSH versus placebo. This is also why it can disturb treated thyroid disease.

False black pepper

Embelia ribes

In one Ayurvedic clinical study, Vidanga Vati taken three times a day for 8 weeks by people with hypothyroidism was reported to lower TSH by about 22% and improve symptoms; this is a single study known from a review, which gives no details of its design or size.

Gypsywort

Lycopus europaeus

In an open two-arm study of patients with low TSH and hyperthyroid symptoms, the herb increased urinary T4 excretion and reduced thyroid-specific symptoms such as a raised morning heart rate over 3 months. An open post-marketing study of 403 patients with mild hyperthyroidism reported 72.6% responders on a Lycopus extract (Thyreogutt mono) versus 41.2% in untreated controls. Neither study was randomised or blinded; two case reports describe Graves' patients who stayed euthyroid on bugleweed-plus-lemon-balm products.

Ningpo figwort

Scrophularia ningpoensis

Extracts lowered T3 and T4 and improved thyroid tissue in rat models of hyperthyroidism, and a xuan shen–fritillaria pair normalised thyroid hormones in rats with drug-induced goitre. Human evidence is lacking.

Self-heal

Prunella vulgaris

Meta-analyses of Chinese RCTs found self-heal preparations added to standard drugs improved outcomes: in thyroid nodules (13 RCTs, 1,468 patients) nodules shrank by about 0.4 cm more with levothyroxine plus self-heal; in hyperthyroidism (17 RCTs, 1,366 patients) thyroid function and gland size improved more than with antithyroid drugs alone; and in Hashimoto's thyroiditis (11 RCTs, 1,215 patients) TPO antibodies fell more. All three reviews rated the evidence low or very low quality.

Zhejiang fritillary

Fritillaria thunbergii

Classically used to disperse nodules and scrofula; it lowered T3 and T4 in hyperthyroid mice.

Bladderwrack

Fucus vesiculosus

From the 16th century it was used in China, France and Britain for goitre caused by iodine deficiency, and later for myxoedema. This use is obsolete: uncontrolled iodine from seaweed can both suppress and overstimulate the thyroid, and EMA advises against combining it with thyroid medicines.

Figwort

Scrophularia nodosa

On Mt Stara Planina in south-eastern Serbia, a leaf tea used only as a gargle was reported for goitre (one informant); also used for goitre in the Deliblato Sands.

Motherwort

Leonurus cardiaca

Commission E (1986) listed it as an adjuvant in an overactive thyroid; the EMA found no clinical data and noted it has no antithyroid activity. Thyroid disease needs medical treatment.