Effect of Certain Herbal Extracts on Hyperthyroidism: A Review

Hyperthyroidism is an endocrine disorder caused by excessive secretion of thyroid hormones, primarily thyroxine (T₄) and triiodothyronine (T₃). This hormonal imbalance leads to metabolic acceleration, cardiac disturbances, neuromuscular hyperactivity and psychological manifestations. While antithyroid drugs, radioactive iodine, and surgical intervention constitute the standard management, many long-term complications including hepatotoxicity, agranulocytosis, recurrence of thyrotoxicosis, and therapy-induced hypothyroidism have encouraged the use of herbal interventions. Medicinal plants such as Ashwagandha (Withania somnifera), Lemon Balm (Melissa officinalis), Bugleweed (Lycopus europaeus), Motherwort (Leonurus cardiaca), Tulsi (Ocimum sanctum) and Brahmi (Bacopa monnieri) possess phytochemicals that modulate thyroid hormone synthesis, regulate the hypothalamic–pituitary–thyroid axis, improve autonomic stability, and attenuate oxidative stress. This review describes the phytochemistry, mechanisms of action, systemic effects, clinical applications, and safety considerations of selected anti-hyperthyroid herbal extracts. Their natural antioxidant properties further support their role as adjunctive or complementary therapies.