Iodine, L-carnitine and glucomannan are some of the natural remedies that treat hyperthyroidism or stave off its symptoms, states WebMD. The body needs iodine but cannot make it, so it must get it from the diet. Most iodine is concentrated in sea life, such as seaweed.
A swollen neck is a result of goiter, a condition where the thyroid gland enlarges because it is made to work harder by the body's feedback systems for lack of iodine, reports WebMD. The thyroid gland needs iodine in order to manufacture hormones.
L-carnitine is another natural remedy to treat an overactive thyroid gland, according to WebMD. L-carnitine is an amino acid naturally produced in the body. However, there are people whose natural level of L-carnitine is too low either because they have a genetic disorder, are under the medication of drugs such as valproic acid or they are undergoing a medical procedure, such as hemodialysis for kidney's disease. L-carnitine works by helping the body to produce energy.
There is speculation that glucomannan can also treat an overactive thyroid gland or stave off its symptoms, according to WebMD. Glucomannan is found in the konjac root. This root is high in soluble fiber that is used to manufacture glucomannan supplements, notes Precision Nutrition.