View photos of the medicinal plant Lycopus americanus (Bugleweed), profiled in Medicinal Plants of the Western Mountain States.

A passage from Medicinal Plants of the Western Mountain States:

Use Bugleweed if stress responses tend to mirror a thyroid surge (or vice versa). Minor basal temperature elevations, weight loss, rapid yet weak heart action, restless sleep, and night sweats are a solid symptom set indicating the plant. It likely will not do much for true hyperthyroidism, but for borderline stages, or when adrenergic/adrenaline responses either appear like or trigger thyroidal spikes, it often does some good.