L- Carnitine for Hyperthyroidism. The Supplement with Drastic Results for hyperthyroid patients
The first studies published in the modern literature on the effects of L carnitine for hyperthyroidism came from post-war Germany in 1959, with the observation that L-carnitine had an impact on the hyper-functioning thyroid. Three years later the same researchers reported on the use of L 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- carnitine for hyperthyroidism 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. They were divided into the following 3 groups:
1. placebo only for six months (Group 0)
2. placebo for two months followed by carnitine 2 or 4 g/day for two months followed by a return to placebo (Groups A2 and A4)
3. Carnitine 2 or 4 g/day for four months followed by placebo (Groups B2 and B4).
By examining the results of supplementation on Group A, the researchers could study the ability of carnitine to treat the effects of hyperthyroidism, since patients wouldn’t get the supplement until after two months of symptom-inducing treatment. By studying the impact of supplementation on Group B they could determine how well carnitine worked to prevent symptoms of the excess hormone levels, since the patients would be getting the supplement right from the start of treatment with thyroid hormones.
The results were nothing short of dramatic. As expected, symptoms and blood chemistry results worsened in Group 0, who received thyroid hormone but only placebo in addition. These women displayed the symptoms of mild hyperthyroidism, including muscle weakness, shortness of breath, heart palpitations, nervousness, insomnia, and tremors. They also had increased knee reflexes and heart rates, and substantial loss of body weight. Women in Group A experienced similar worsening of symptoms during the two months that they initially took placebo, but those symptoms disappeared after two months on the carnitine supplementation, only to return during their final two months of placebo. Meanwhile, women in Group B, who took carnitine from the start of their thyroid hormone treatment, had no worsening of their symptoms until they stopped receiving carnitine at the end of the first four months.
They then rapidly developed symptoms similar to the other subjects who were not receiving carnitine.
There were improvements in certain laboratory parameters as well during the times that the subjects supplemented with carnitine.
Of particular interest was the fact that bone mineral density increased in both supplemented groups, with the greatest increase in Group B, who received carnitine supplementation for a full four months.
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 for hyperthyroidism 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
However, I strongly advise you to check with your physician. There is nothing worse than taking a supplement that may not be for you, as other factors may interhere.
Sinclair C, Gilchrist JM, Hennessey JV, Kandula M. Muscle carnitine in hypo- and hyperthyroidism. Muscle Nerve. 2005 Sep;32(3):357-9.
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Strack E, Bloesche H, Bemm H, Rotzsch W. Use of L-carnitine in hyperfunction of the thyroid gland. Dtsch Z Verdau Stoffwechselkr. 1962 Apr;21:253-9.
Willgerodt H, Rotzsch W, Strack E. Effect of carnitine of the accumulation of iodine in the thyroid gland. Dtsch Z Verdau Stoffwechselkr. 1965 Aug;25(3):127-35.
Emmrich R. New methods for the diagnosis and therapy of hyperthyroidism. Munch Med Wochenschr. 1967 Oct 27;109(43):2217-21.
Maebashi M, Kawamura N, Sato M, Imamura A, Yoshinaga K. Urinary excretion of carnitine in patients with hyperthyroidism and hypothyroidism: augmentation by thyroid hormone. Metabolism. 1977 Apr;26(4):351-6.