Background: Plant extracts from species of Lycopus (bugleweed) and Melissa officinalis (lemon balm) have long been used as folk remedies in the treatment of hyperthyroidism 1. In vitro studies have shown that extracts from bugleweed and lemon balm inhibit stimulation of thyroid hormone production by both TSH and Graves’ antibodies 1. An in vivo study in rats showed that oral bugleweed extract alters extra-thyroidal T4 conversion 2.
Case 1: A 64 year-old woman presented for routine examination and was found to have a TSH of 0.01 mIU/L on 6/6/2016. Labs the next month showed FT4 1.4ng/dL (0.8-1.8) and FT3 4.7pg/mL (2.3-4.2). TSI was elevated to 275% (Normal<140%), consistent with Graves’. She did not have symptoms of hyperthyroidism. The patient’s cat had been treated for hyperthyroidism with Thyrosoothe (TS), a formulation containing extracts from bugleweed and lemon balm. After being diagnosed with hyperthyroidism, the patient began taking TS. On 9/12/16 the patient’s labs were improved with TSH 0.02mIU/L, FT4 0.88 ng/dL (0.8-1.8) and Total T3 86 (76-181). Three months later, the patient’s TSH was 1.89 with normal FT4, Total T3 and TSI. She took TS for 9 months. Her thyroid function tests have remained normal since starting TS, without the need for any other anti-thyroid medications.
Case 2: A 46 year-old female presented with periorbital edema in July 2018 and was referred to an ophthalmologist, who diagnosed her with thyroid eye disease. She was also complaining of palpitations and “jitteriness”. She was found to be hyperthyroid on labs and was treated with methimazole (MMI) between August 2018 and February 2019, requiring doses of up to 10mg BID. In March 2019 she stopped MMI due to transaminitis and began taking a thyroid tincture containing bugleweed and lemon balm extract. She has remained euthyroid on the herbal tincture, her transaminitis has resolved, and she has not required any further anti-thyroid medication. Her TSI, which was 0.84 IU/L (Normal<0.55) in May 2019, normalized to 0.36 IU/L in June 2020, after 15 months on this tincture, which she is still taking.
Conclusion: In vitro and rat studies of bugleweed and lemon balm extract have demonstrated anti-thyroidal effects. This is the first report of the use of these plant extracts in the treatment of two patients with Graves’ disease, in whom it led to restoration of euthyroidism and normalization of TSI titers. Further study of the anti-thyroidal effects of bugleweed and lemon balm in humans is warranted to evaluate its potential role as an adjunctive therapy in Graves’ disease.References: 1. Auf’Mkolk, M., et al. “Extracts and Auto-Oxidized Constituents of Certain Plants Inhibit the Receptor-Binding and the Biological Activity of Graves’ Igs*.” Endocrinology, vol. 116, no. 5, May 1985, pp. 1687–93. 2. Winterhoff, H., et al. “Endocrine Effects of Lycopus Europaeus L. Following Oral Application.” Arzneim. Forsch., vol. I, no. 44, 1944.