Levothyroxine (Synthroid) is a synthetic form of thyroxine (T4), one of the main hormones produced by your thyroid. It is used to treat thyroid conditions, most commonly hypothyroidism, which occurs when the thyroid gland doesn’t produce enough thyroid hormone.

By restoring normal thyroid hormone levels, levothyroxine helps regulate metabolism, support energy levels, and treat hypothyroidism. It may also help prevent dangerous complications from thyroid conditions, including myxedema coma.

Because thyroid hormone plays a key role in metabolism, untreated thyroid conditions can also affect how the body responds to weight-loss treatments, including medications like GLP-1 drugs. Addressing thyroid health is an important part of overall metabolic care.

Regular blood tests help ensure your dosage is accurate. Sesame can also help you access thyroid blood tests, including TSH testing, with convenient lab options available nationwide.

Levothyroxine (Synthroid) starts affecting your thyroid hormone levels soon after you begin taking it, but symptom improvement may take a few weeks. Full benefits, like increased energy, better metabolism, and relief from hypothyroid symptoms, can take several weeks to months as your hormone levels stabilize.

Consistency in taking the medication is important, and you should not discontinue use or alter your dosage without consulting your healthcare provider first. This could lead to thyroid hormone imbalances and related symptoms.

Thyroid conditions can affect women differently at various life stages. Learn more about how thyroid problems affect women.

Certain foods and drinks can interfere with absorption. Avoid taking levothyroxine (Synthroid) with high-fiber foods, soy products, or walnuts, and do not consume grapefruit or grapefruit juice while on this medication.

Tell your healthcare provider about any prescription drugs, over-the-counter medications, or supplements you’re taking to avoid drug interactions. This includes:

• Antiarrhythmics, beta-blockers, and cardiac glycosides
• Antacids, proton pump inhibitors, and mucosal protectants
• Anticoagulants and diuretics
• Cancer medications and tyrosine kinase inhibitors
• Hormone therapies, including estrogen-containing contraceptives
• Anticonvulsants, antidepressants, SSRIs
• Antibiotics, lipid-lowering agents, corticosteroids
• Cough, cold, or weight loss medications
• Cholesterol-lowering drugs such as cholestyramine and colestipol
• Other thyroid or hormone medications

Always check with your provider before starting any new medication, supplement, or major dietary change while on levothyroxine.

Levothyroxine (Synthroid) may not be suitable for everyone. People with certain medical conditions, such as adrenal insufficiency (a condition affecting the adrenal glands), heart disease, diabetes, atherosclerosis, bleeding or blood disorders, pituitary gland disorders, osteoporosis, or liver disease, may need special precautions or may not be able to take it safely. Talk to your doctor if you are taking lanthanum for kidney disease.

If you are pregnant, planning to become pregnant, or breastfeeding, it’s important to talk with your healthcare provider before starting levothyroxine. Your provider can help weigh the potential risks and benefits and determine the safest dose.

Some patients may also benefit from broader hormone testing. Learn more about [getting comprehensive female panel lab tests online](https://sesamecare.com/blog/can-you-get-comprehensive-female-panel-lab-tests-online.

Taking too much levothyroxine (Synthroid) can cause symptoms of excess thyroid hormone, including rapid or irregular heartbeat, chest pain, anxiety, tremors, sweating, weight loss, or difficulty sleeping.

If you suspect an overdose, seek medical attention immediately or call your local poison control center. Always take levothyroxine exactly as prescribed, and talk to your healthcare provider if you feel your dose may need adjusting. Never take extra doses to try to improve results.

You will need an initial prescription from a licensed healthcare provider to get levothyroxine (Synthroid). A Sesame provider can determine if levothyroxine is appropriate for you during a telehealth visit, reviewing your medical history, current medications, and thyroid-related symptoms. The decision to prescribe levothyroxine is always made by your healthcare provider.

Levothyroxine is available under various brand names, including Synthroid, Levoxyl, and Tirosint; Levothroid has been discontinued.

Levothyroxine (Synthroid) is currently only available via prescription. This means the use of this drug must be authorized by a licensed healthcare provider.

If you're looking for a prescription, book a telehealth appointment to talk to a provider who can write a new prescription or refill an existing prescription. Depending on the medication, you can arrange for same-day pickup at a pharmacy near you.

Note that all prescriptions are at the discretion of your healthcare provider. Providers on Sesame cannot prescribe controlled substances.

Levothyroxine (Synthroid) is the most commonly prescribed treatment for hypothyroidism, but it’s not the only option. In some cases, providers may prescribe liothyronine (generic for Cytomel), a synthetic form of the T3 thyroid hormone.

Your healthcare provider can help determine which medication or combination of medications is most appropriate based on your thyroid levels, symptoms, and overall health history.