Synthroid (Levothyroxine) prescription available online

If you suffer from hypothyroidism, enlarged thyroid glands, or thyroid cancer, Synthroid can help. Get a new prescription or refill of Synthroid today from a board-certified doctor online.*

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About Synthroid 

Synthroid is considered a thyroid drug, which increases the concentration of thyroid hormone levels in the body. Like any thyroid hormone drug, this medication can only be used for hypothyroidism. It is ineffective against hyperthyroidism because it will not help decrease thyroid hormone levels.

Some conditions that Synthroid is known to treat include hypothyroidism and a specific type of thyroid cancer. Synthroid is available only by prescription. It is available in a generic formulation under different brand names, including levothyroxine.

Synthroid may be prescribed as a tablet. It's always important to follow the specific instructions on your prescription, as they can vary based on the formulation and dosage you are prescribed.

Only stop taking your levothyroxine doses if your doctor tells you to. This may cause the problems with your thyroid gland to resurface. In turn, thyroid hormone levels can start to decline again. Tell your doctor about any unpleasant or unexpected side effects that you experience. This can help them understand if you get enough thyroid hormone through this medication.

Synthroid uses

There are two FDA-approved uses for Synthroid, but it may also be used off-label to treat other conditions. Your online medical professional may prescribe it for the following reasons. It’s also possible that your healthcare provider may prescribe it for different reasons not listed here. Ask your online doctor or pharmacist if you have questions about how it is prescribed.

  • Hypothyroidism

    If a person has hypothyroidism, it means their thyroid gland does not produce enough hormones. This gland is located in the neck and produces two essential thyroid hormones. Each of these hormones plays an important part in metabolism and several other bodily functions. Synthroid can help provide additional thyroid hormones when the thyroid gland cannot keep up with the body's requirements. Taking the medication regularly can help to give a better balance in these hormones, which also reduces the symptoms caused by hypothyroidism.

  • Thyroid Cancer

    In some rare cases, a doctor may use Synthroid and other drugs to treat thyroid cancer. If the patient recently received radiation therapy, their thyroid gland may not produce enough hormones to support their body. This may continue for several weeks, which can lead to the onset of hypothyroidism symptoms. In this case, Synthroid is used to treat this side-effect of radiation therapy.

What are the pros and cons?



  • Improves metabolism

  • Restores hormone levels

  • Used for decades with a known efficacy and safety profile


  • Taken every day at the same time

  • Best absorbed on an empty stomach

  • Regular blood tests needed to monitor thyroid levels and adjust dosage

Synthroid side effects

  • The side effects associated with taking Synthroid are typically mild. Most Synthroid side effects are associated with the gastrointestinal tract and muscles. Synthroid has some common side effects. They may include:

    • Irregular menstrual periods in female patients

    • Rash on the skin

    • Muscle aches

    • Fast or irregular heartbeats

    • Shortness of breath

    • Muscle weakness

    • Hair loss

    • Anxiety

    • Irritability

    • Sleeping problems

    • An increased appetite

    • Diarrhea

    Some patients experience weight gain or weight loss when they take Synthroid. The weight gain should usually stop after taking the medication for a few weeks. If not, the patient may gain too much weight, which warrants the need to treat obesity in the long term.

    Other side effects, which are less common but might be more severe, could include:

    • Cardiovascular Problems: Some patients experience heart problems when Synthroid is used to treat hypothyroidism. This may cause an irregular heartbeat. Some patients complain about heart palpitations. Dizziness, high blood pressure, and shortness of breath are also symptoms of cardiovascular problems. There is also a rare but potentially fatal risk of a heart attack while using this medication.

    • Allergic Reaction: Patients may sometimes experience an allergic reaction to the main ingredients in this drug. This can cause serious side effects. Tell your doctor if you previously experienced serious side effects when taking levothyroxine. You should also tell your doctor if you have had allergic reactions to other medicines in the past.

    • Low Bone Mineral Density: It has also been found that Synthroid may affect bone mineral density. This increases the risk of fractures. This particular complication is usually only relevant to cases where people take too many levothyroxine tablets with each dose. A healthcare professional can determine the right dose and help you prevent large doses from affecting your bones.

    You should call your doctor if you notice any of these side effects or if you develop any other new or concerning symptoms.

    In some cases, children may also be provided with this medication. In this situation, less levothyroxine is provided compared to older adults. There are also different side effects that have been noted among pediatric patients.

How to take Synthroid

Your pharmacist will provide you with instructions on how to take your Synthroid prescription.

Be sure to read your prescription label and follow the instructions. Call your doctor or pharmacy if you have any questions.

Synthroid can come in different forms and doses, so be sure to follow the specific instructions on your prescription. It is typically prescribed one time per day. Some specific instructions may include how you should ideally administer the medication.

There are certain cases where you will use two doses. You start with an initial dose that only contains a small concentration of levothyroxine. The doctor can give you advice about side effects you may experience during this time. The dosage may then be increased over time to help reduce the risk of certain side effects.

What to avoid while taking Synthroid

Synthroid can cause interactions with certain drugs. Don’t change what you are taking without checking with your doctor or pharmacist. That includes other medications or supplements, as well as over-the-counter drugs. 

Some of the drug interactions that can occur include the use of:

If you take levothyroxine, tell your doctor about any over-the-counter or herbal products you use. These can sometimes also lead to drug interactions.

Ask your doctor or pharmacist if it is acceptable to consume alcohol while taking Synthroid. There is limited information available regarding the potential interaction between alcohol and levothyroxine. Thus, if you take levothyroxine and want to drink alcohol, ask your doctor for medical advice.

Medication alternatives to Synthroid

If your healthcare provider prefers to put you on another treatment altogether, they may suggest another medicine in another drug class. Here are some common doctor-recommended alternatives based on your health issue:

  • Allergic Reaction To Levothyroxine

    Some patients experience allergic reactions when they take levothyroxine. In this case, the healthcare provider will look at alternative options that they can use to increase levels of thyroid hormones.

    Cytomel (Liothyronine)

Synthroid prescription FAQs

  • How much does Synthroid cost?

    Synthroid is available in both a brand name and generic version. The one you use will largely impact its overall price. You also have to consider the dosage that you are prescribed. A higher dose will cost more.

  • How can I refill my Synthroid prescription?

    You will generally take Synthroid over a long period of time. This is why it is a good idea to keep the prescription with the local pharmacy you prefer to use. You can then also ask the pharmacists medical advice about side effects and other questions you may have.

  • What should I avoid taking with Synthroid?

    Do not take Synthroid with drugs that may also affect the level of thyroid hormones in your body. You also have to ensure you do not take medication that can cause drug interactions while taking levothyroxine.

  • What are the rules for taking Synthroid?

    Timing is a particularly important role. Synthroid works best when taken on an empty stomach, which is why many people take it first thing in the morning. Take it at the same time every day and avoid taking levothyroxine with other medicines.

  • Why should you not take Synthroid?

    Synthroid is not appropriate for people who have hyperthyroidism. You should also not take Synthroid if you have problems with the pituitary gland, or frequently experience chest pain. Be careful about using Synthroid if you are a diabetic or have a high risk of osteoporosis.

  • How long does it take for Synthroid to take full effect?

    As the body adjusts to the medication, you will start to notice results, but this does not happen immediately. Most people report improvements in their symptoms after taking levothyroxine for a period of six weeks. Some people may find that it takes a bit longer before they can really feel the effects. This usually happens in cases of more severe hypothyroidism.

  • Who should not take Synthroid?

    You should not take levothyroxine if you want to experience weight loss primarily with the drug. The medication is only meant to be used to treat hypothyroidism. While hypothyroidism and obesity are often seen together, it will not treat obesity on its own. If you are obese and have hypothyroidism, it is a good idea to combine the use of Synthroid with lifestyle changes that can help with weight loss. This includes a healthy diet, as well as exercise. Adding more dietary fiber to your diet, for example, can already help to reduce the amount of calories you consume by keeping you full.

  • What happens if I miss a dose of Synthroid?

    Skip the missed dose if it is almost time for your next dose. If there is still a sufficient period of time left between the doses, then take the missed dose. Call your doctor for medical advice if you are not sure if there is still enough time left between the two doses.

  • What happens if I take too much Synthroid?

    Never take levothyroxine in doses that are higher than what the doctor prescribed for you. Your doctor will analyze several factors to determine the right dosage for you. If you take more of the levothyroxine, then you may experience serious complications. This does not only include partial hair loss and leg cramps, but could also interfere with issues like heart disease. Call your doctor immediately if you think you took too much of the medication. They can provide you with further instructions and actions to help you avoid serious complications. Your doctor may also recommend visiting an emergency department for assistance.

3 simple steps to request your Synthroid prescription today 

Step 1

Book a Synthroid prescription request appointment.

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Step 2

Talk to your medical provider regarding your Synthroid prescription.

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Step 3

Pick up your Synthroid prescription.

We can send prescriptions to any local pharmacy.

Synthroid prescription pricing details

How pricing works

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30 days of free membership

  • Same-day appointments 7 days a week

  • Unlimited messages with your Care Team

  • Prescription discount card to save up to 80%

  • Exclusive discounts on lab tests

  • Free memberships for your family

  • Cancel anytime

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Initial visits are $129.

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PlushCare is dedicated to providing you with accurate and trustworthy health information.

  • Doctors have prescribed synthroid for over 60 years to keep thyroid hormone levels in balance. Synthroid Official Website. (n.d.). Accessed on October 10, 2023,

  • Synthroid uses, dosage & side effects (no date) Accessed on October 10, 2023,

PlushCare content is reviewed by MDs, PhDs, NPs, nutritionists, and other healthcare professionals. Learn more about our editorial standards and meet the medical team. The PlushCare site or any linked materials are not intended and should not be construed as medical advice, nor is the information a substitute for professional medical expertise or treatment.