I Stopped Taking Levothyroxine And Lost Weight (Possible Reasons)

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One possible reason you’re not losing weight on levothyroxine is that you expect to see results immediately. It doesn’t happen within 3-5 days. It usually takes 12-24 weeks before you start seeing some results. Another thing is that your body might haven’t absorbed the medicine properly because you’re taking it at the wrong time or you’re suffering from some digestive illnesses. You could also be underdosed or haven’t found the drug that works for your thyroid.

Levothyroxine is a long-term medication. So it’s dangerous to suddenly stop taking it, change your dosage, and switch brands or manufacturers without your doctor’s permission. 

Stopping levothyroxine won’t make you lose weight. On the contrary, it might even do the reverse-that is, cause weight gain. 

Most patients on levothyroxine experience weight loss. But, are you not seeing any difference in your weight? Should you stop taking levothyroxine? 

Below, we’ll discuss levothyroxine and its effect on your body.

What is thyroxine?

So, it all starts with your hypothalamus, a small part of your brain that controls the endocrine system.

It releases thyrotropin-releasing hormone (TRH) that stimulates your pituitary gland to produce thyroid-stimulating hormone (TSH). 

The TSH prompts your thyroid gland to produce thyroxine (T4) and L-triiodothyronine (T3) hormones. 

Thyroxine hormones are inactive.

Once released from your thyroid gland, your liver and kidneys will convert about 50% of the T4 hormones into L-triiodothyronine (T3). 

These activated hormones help control and regulate your metabolic rate, circulatory and digestive functions, muscular control, cognitive function, brain development, and bone maintenance.

If your thyroid gland doesn’t produce enough thyroxine, you may be diagnosed with hypothyroidism.

A woman is clenching her throat because she's feeling pain from her thyroid area

When the problem is in your thyroid gland, it’s known as primary hypothyroidism. 

Meanwhile, it’s called secondary hypothyroidism if the problem is in your pituitary gland. 

Tertiary hypothyroidism occurs when the problem is in your hypothalamus. 

This condition slows down many bodily functions affecting your heart rate, breathing, metabolism, digestion, and mood. 

What is levothyroxine?

📌 Levothyroxine (Levoxyl, Synthroid) is a synthetic form of thyroxine hormone which replaces or adds on the missing T4 hormones that your underactive thyroid gland can’t produce. It’s supposed to be used as a long-term medication. 

Stopping it might cause your hypothyroidism symptoms to recur. Below are the following:

Levothyroxine must be taken as prescribed by your doctor.

It would be best if you took the same dose from the same manufacturer or brand at all times to get the best results.

For better absorption of the medicine, take it on an empty stomach- about 30 to 60 minutes before breakfast or 3 to 4 hours after dinner. 

Do not take levothyroxine within 4 hours after having food or supplements containing iron or calcium.

What happens after a missed dose of levothyroxine?

It may take time before your body gets rid of levothyroxine. 

So, missing or forgetting a dose should not be a severe problem for patients who have been taking the drug for quite a long time. 

T4 hormones may still be in your bloodstream for about a week. 

However, missing a dose may be bad news for patients who have just started taking levothyroxine. 

It’s because your doctor is still testing how much dosage you need. 

A forgotten dose might mess up your progress and throw off your lab results.

What to do if you miss a dosage

A woman is holding out her medicine that she's about to take with a glass of water

Take your missed dose as soon as you remember. If you only realize it by the time you’re about to take your next dose, skip it and resume taking it on your usual schedule. 

Never take a double dose to make up for your first one. 

Please consult your doctor immediately if you have forgotten to take two or more doses in a row. 

Side effects of levothyroxine

Don’t take levothyroxine for weight loss, as it may cause dangerous side effects. 

Most side effects you will experience while taking levothyroxine may be due to the medication dosage being incorrect. 

The following are the side effects that you may experience:

  • Nausea and vomiting
  • Feeling extra irritable
  • Tremors
  • Headache
  • Diarrhea
  • Chest pain and shortness of breath
  • Joint and muscle pain
  • Leg cramps
  • Sudden fever
  • Excessive sweating or heat intolerance
  • Changes in your appetite
  • Changes in your menstrual cycle (in women)

Please consult your doctor immediately if the following symptoms worsen over time. 

Some severe side effects of levothyroxine may include:

Long-term side effects of levothyroxine

1. Osteoporosis

Taking levothyroxine may increase your rate of bone loss, especially when you’re on the medication and are already at risk of osteoporosis

Your levothyroxine dosage should match your body’s requirements to avoid speeding up bone loss. 

2. Cardiovascular problems

Heart problems may arise when your body doesn’t have enough thyroid hormones. 

A woman is having chest pain after taking her thyroid medication

Meanwhile, getting a high dosage of levothyroxine will put you at risk of abnormal heart rate, palpitations, chest pain, and even heart failure or heart attack.

When your dose is too low, you’re at increased risk of high cholesterol levels, which could lead to heart disease. 

That is why it’s essential to work closely with your doctor in treating your hypothyroidism.

It’s best to do regular blood and hormone level tests to ensure you’re on the correct dosage of levothyroxine.

How long does it take to lose weight after taking levothyroxine?

📌 It would usually take 12 to 24 weeks to find the correct dosage of levothyroxine that you need and start seeing results.

When taken orally, levothyroxine usually works within 3-5 days if absorbed entirely by your body. 

But, of course, you’re still not in your correct dosage during these times, which means that it would take several weeks (about 4-6 weeks) to work with your doctor to figure out how much levothyroxine you need. 

Expect many laboratory tests and changes in your dosage before you can experience significant relief from your hypothyroidism symptoms and notice weight loss.

Does levothyroxine increase metabolism?

Weight gain is probably one of the most frustrating symptoms of hypothyroidism. 

Hypothyroidism may slow down your metabolism and causes you to retain water and salt. 

Thus, even if you cut down on calories, eat healthily, and exercise regularly, you will still gain weight because your body will have a hard time burning calories. 

Taking levothyroxine may increase your metabolism and helps your body to start getting rid of the extra water and salt, resulting in weight loss.

The weight you’ve gained before treatment may be reversed, which would be noticeable early in your treatment. Also, note that your weight loss depends on how long you’ve lived with untreated hypothyroidism and how severe it is. 

Some patients on levothyroxine have reported losing about 8-9 pounds during the first 24 months of their treatment.

Weight loss because of levothyroxine is mostly losing the excess water you’ve had in your body. 

Experts have found that losing weight on levothyroxine may not rid the extra fat in your body nor affect your bone mass.

Why are you not losing weight on levothyroxine?

As mentioned above, levothyroxine can cause you to reverse your weight gain because of hypothyroidism. 

But, there are cases when the numbers don’t go down on your scale. Below are the possible reasons why this could happen.

1. You are impatient

Remember the golden rule, which is to be patient. 

Treating hypothyroidism isn’t like magic you can feel instant relief. It would take several weeks before the medicine would work on your symptoms. 

Most of the time, you aren’t given the correct dosage of the drug during your initial treatment. 

There will be many adjustments with your dosing, and when your doctor finally figures out how much you need, you will have to maintain that dosage for several weeks to months before you can finally see some changes.

2. It might not have been absorbed

Of course, you would think that any medicine you put in your mouth would be absorbed, right? 

Well, that’s not the case with levothyroxine. 

Taking the drug within 4 hours after your meal will disrupt the drug from being absorbed within your body.

It won’t also be absorbed if you have it with coffee or other medicines and supplements. 

Conditions like irritable bowel syndrome, gluten intolerance, SIBO/SIFO, and acid reflux may also interrupt your drug absorption.

Even if you’re taking the correct medicine dosage, it won’t work when it doesn’t get absorbed by your system.

3. You are underdosing

There’s a high chance that your doctor might have prescribed you a lower dosage of levothyroxine.

 It will result in the medicine not working correctly.

4. Levothyroxine may not be for you

Doctors would commonly prescribe levothyroxine in treating thyroid conditions like hypothyroidism. 

But, maybe this drug isn’t for you, and you could find relief with other alternatives. There are other drugs available that may work best for you than levothyroxine.

Of course, it would take time and effort with your doctor’s supervision to find out what it is. 


What does a thyroid storm feel like?

It’s a life-threatening condition that may lead to death.

When hyperthyroidism is left untreated or not adequately treated, you will experience severe symptoms such as abnormal heartbeat, high fever, shaking and tremors, high blood pressure, excessive sweating, agitation, and confusion. 

Please call emergency help immediately when you experience these symptoms.


Thyroid hormones regulate many bodily functions such as heart rate, breathing, metabolism, digestion, and mood.

When problems occur in the production of your thyroid hormone, specifically thyroxine, your metabolism may slow down, resulting in weight gain.

Taking levothyroxine will replace your body’s missing thyroid hormones, relieving hypothyroidism symptoms and reversing your weight gain.

Stopping this medication without your doctor’s permission could make your hypothyroidism symptoms to recur.

Without enough thyroid hormones in your system, your body will have difficulty converting the food you eat into energy resulting in weight gain.

Weight loss on levothyroxine is mostly water weight, which means you should work with your doctor on how to lose weight effectively once you’re on the medication. 

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Reana Jean Cuevas
Mabuhay! I'm Reana Jean Cuevas. A healthy body means living well with no worries-just happiness and more life adventures. Taking care of my body and well-being is an investment for my career and future. I was a volunteer at the Philippine Red Cross. I joined the training to become a first-aider and be able to provide other health and safety services in my community. I love discussing anything but mainly first-aid, home remedies, and women's health.

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