L- carnitine and its effect on Graves’ disease

L-carnitine is an amino acid that is very important for energy production and fat metabolism and it is often depleted in hyperthyroidism. It helps to carry fatty acids into mitochondria, the energy houses of cells.

L-carnitine, known as acetyl-L-carnitine or carnitine, is synthesised in the liver, kidney and brain and then transported to other areas of the body. It is also present in some foods like red meat and avocado. In order for carnitine to be made in the body, essential amino acids, such as lysine, methionine, vitamins: B3 (niacin), B6 and iron are required. It is possible that vitamin B3 may be depleted in people with leaky gut problems and digestive problems (common with autoimmunity) as vitamin B3 and amino acid- tryptophan are not well absorbed. Tryptophan is used for vitamin B3 and serotonin production (the happy hormone) in the body.  In fact Graves’ disease may be triggered by diets low in tryptophan, as was shown in animal studies (2). People with Graves’ disease need to have adequate protein (as proteins are made up of amino acids) and fats in their diet. L tryptophan is an essential amino acid, present in high protein foods such as nuts, seeds, egg whites, cheese, red meat, chicken, turkey, fish, oats, beans and lentils. Therefore, indirectly, leaky gut, digestive issues and a low protein (and low tryptophan) diet may be related to a low L-carnitine level.

L- carnitine may help with Graves’ disease. A scientific trial involving fifty women found carnitine to be effective in reversing and preventing the symptoms of hyperthyroidism (1). Its action seems to be similar to antithyroid drugs. Carnitine may inhibit the passage of thyroid hormone into the nucleus or it can interfere with the action of excessive T3 at the nuclear receptor. It seemed to be a very important nutrient in the methylation processes of the body. There is indication that an aberrant methylation process may play a role in the development of GD.

The usual dose of L-carnitine is 500-2,000mg/day. It is available in tablet or liquid form and can be easily obtained as a supplement without a medical prescription.

Some people take L-carnitine with their antithyroid medications but it is best done under a medical supervision as lower doses of antithyroid medication may be needed when taking L-carnitine.

Consult your doctor before using L- carnitine as it needs to be used with caution when taking anticoagulants (blood thinners), beta-blockers, or calcium channel blockers as well as in certain medical conditions. Avoid if pregnant or breastfeeding and with a known allergy or hypersensitivity to carnitine.


  1. Benvenga S, Ruggeri RM, Russo A, Lapa D, Campenni A, Trimarchi F. Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial. J Clin Endocrinol Metab. 2001 Aug. 86(8):3579-94.
  2. Carew, L.B. Jr, Alster, FA, Foss, DC and Scanes CG. Effect of tryptophan deficiency on thyroid gland, growth hormone and testicular functions in chickens. J. Nutr. 1983 Sep; 113(9):1756-65.

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