Natural remedy
L-carnitine
Evidence grade B · Traditional use recognisedRCT: eased hyperthyroid palpitations, tremor, and weakness
Why it may be relevant
If a racing heart, tremor, muscle weakness, and fatigue are hitting hardest, L-carnitine acts as a peripheral blocker of thyroid hormone inside tissues and was tested for exactly these hyperthyroid symptoms.
In a randomized, double-blind, placebo-controlled trial, oral L-carnitine both reversed and helped prevent hyperthyroid symptoms such as palpitations, tremor, and weakness, and supported bone density measures. Use it alongside - not instead of - your prescribed thyroid treatment.
Dose or use Studied at 2-4 g daily by mouth; consult a healthcare practitioner, especially about timing around your thyroid medication.
Key study Randomized controlled trial (2001, PMID 11502782): Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism - a double-blind, placebo-controlled trial in which L-carnitine reversed and helped prevent hyperthyroid symptoms.