Thyroid hormone generally controls the pace of all of the processes in the body. This pace is called your metabolism. If there is too much thyroid hormone, every function of the body tends to speed up. The thyroid gland regulates the body temperature by secreting two hormones that control how quickly the body burns calories and energy. If the thyroid produces too much hormone, the condition is called hyperthyroidism, but if too little is produced the result is hypothyroidism.



The first studies published in the modern literature on the effects of carnitine in hyperthyroidism came from post-war Germany in 1959, with the observation that carnitine had an impact on the hyper-functioning thyroid.

Three years later the same researchers reported on the use of carnitine in the treatment of hyperthyroidism; they subsequently demonstrated that carnitine affected the accumulation of iodine in thyroid tissue itself. In the 1970s, Japanese researchers found also that there was an increase in carnitine excretion in the urine of hyperthyroid patients.

Carnitine is an essential nutrient for transporting fuel (mostly fatty acids) into the cellular "furnaces" known as mitochondria. As muscle cells burn fatty acids in a wasteful response to increased thyroid activity, carnitine turnover is dramatically increased, using up cellular stores of carnitine while potentially contributing to the increased urinary losses at the same time.

The most recent discoveries regarding L- canitine are done by the Italian endocrinologist Dr. Salvatore Benvenga and his colleagues in 2004. He conducted a double-blind, placebo-controlled trial and their subjects were 50 women who would be taking thyroid hormones to treat benign thyroid nodules (thyroid hormone suppresses the pituitary hormone called thyroid-stimulating hormone, or TSH, which causes the nodules to grow).

In such patients, mild-to-moderate hyperthyroidism is frequently an undesired side effect, and the researchers chose to study this group of patients in order to capitalize on that effect, while potentially providing welcome relief from symptoms.

The results were nothing short of dramatic. Dr. Benvenga and colleagues summarized their findings from these studies in the following fashion: "Since hyperthyroidism impoverishes the tissue deposits of carnitine, there is a rationale for using L-carnitine at least in certain clinical settings... and since carnitine has no toxicity, teratogenicity [birth defects], contraindications, and interactions with drugs, carnitine can be of clinical use." To date, clinical trials have shown that doses of 2,000-4,000 mg/day of L-carnitine are helpful in individuals who suffer from hyperthyroidism. Future studies may uncover similar benefits of other carnitine formulations such as acetyl-L-carnitine, acetyl-L-carnitine arginate, and propionyl-L-carnitine, along with the doses needed to match the efficacy provided by 2,000-4,000 mg L-carnitine.

Until scientists reveal the most effective dosages of each carnitine formulation, the following chart may provide preliminary guidance for individuals seeking relief from the effects of hyperthyroidism:

L-carnitine:2,000-4,000 mg/day

Acetyl-L-carnitine: 800-2,000 mg/day

Acetyl-L-carnitine arginate: 600-1,000 mg/day

Propionyl-L-carnitine: 600-2,000 mg/day

So when treating Hyperthyroidism or overactive thyroid and Graves' Disease in particular, do not overlook other alternative methods and treatments.