How to Successfully Lose Weight When You're Taking Synthroid

Synthroid, weight loss, diet, weight gain, hypothyroidism, hypothyroidism medication
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Are you wondering how to lose weight while being treated for hypothyroidism? Are you taking Synthroid, a brand-name levothyroxine, or other brands such as Levoxyl or Tirosint? Or are you taking a natural desiccated thyroid (NDT) drug like Nature-throid or Armour, and still struggling to lose weight? If you are on Synthroid or another thyroid hormone replacement to treat your hypothyroidism, but you are struggling with diet and weight loss, there are some important things you should know. 

You Need to Properly Absorb Your Thyroid Medication

When you are hypothyroid, it's essential that your thyroid medication is effective. That starts with proper absorption. Make sure that you are not taking or doing anything that can interfere with maximum absorption. Here are some helpful guidelines:

  • Take your thyroid medication in the morning, and wait at least an hour before drinking regular or decaf coffee or milk, or eating. Wait at least three to four hours before taking any supplements that contain iron or calcium, or drinking calcium-fortified juice. 
  • If you are taking Synthroid brand levothyroxine, keep in mind that Synthroid contains both acacia and lactose, which are allergy-provoking ingredients for some people. If you have sensitivities or allergies, consider switching to another brand. 
  • If you have digestive issues or any digestive conditions such as irritable bowel syndrome or Crohn's disease, talk to your doctor about Tirosint. This is is a specialized, hypoallergenic, liquid levothyroxine in a gelcap, designed to improve absorption. 

Make Sure You Are Taking Enough Medication

It's important that you take enough Synthroid or other thyroid hormone replacement drug. Some practitioners may prescribe only enough medication to get your thyroid stimulating hormone (TSH) level into the upper end of the reference range, close to the cutoff for hypothyroidism. This may not be enough to resolve your symptoms or optimize your metabolism. Many thyroid patients and practitioners find that a TSH level below 2.0 is optimal for resolution of symptoms. If your TSH is at the higher end of the reference range, talk to your doctor about increasing your dosage of thyroid medication.

You May Need to Add T3

Levothyroxine drugs like Synthroid are a synthetic form of the thyroid hormone thyroxine, also known as T4. When everything works perfectly, your body should convert the T4 into the second key thyroid hormone, triiodothyronine, known as T3. T3 is the active hormone that helps facilitate energy and oxygen reaching your cells. Research shows, however, that in a subset of thyroid patients, this conversion process is faulty. Whether due to genetic changes, stress, or nutritional deficiencies, these patients fail to effectively convert enough T4 into T3. If you fall into this category, you may find that even after being treated with a Levothyroxine drug like Synthroid, you may still be gaining weight, or unable to lose weight. You may also have a number of other hypothyroidism symptoms, such as fatigue, hair loss, or brain fog.  

Here are some guidelines:

  • Ask your doctor to test your free triiodothyronine, known as T3. If you have low or low-normal levels, you may want to ask your healthcare provider about adding T3. This can be done with brand-name drug Cytomel, the generic T3 drug liothyronine, or a prescription, compounded, time-released liothyronine.  
  • If your free T3 levels are normal, but you have noticeable hypothyroidism symptoms including weight loss challenges, ask to have your reverse T3 tested. High levels of this inactive form of T3 may interfere with your body's ability to deliver active T3 to your cells and organs. Adding T3 to your treatment, in this case, may help resolve your symptoms.

You Might Need Natural Desiccated Thyroid

Some thyroid patients try a Levothyroxine drug like Synthroid, different brands, and add a T3 drug, and still can't resolve symptoms. If that is your experience, you may want to talk with your practitioner about trying a natural desiccated thyroid (NDT) drug like Nature-throid or Armour Thyroid. There is also a generic version of NDT known as Thyroid NP.  There is limited research on NDT, but one useful study found that NDT was a safe and effective alternative to levothyroxine drugs, and resulted in more weight loss for patients

A Word from Verywell

While it's not related to your Synthroid or other thyroid drug treatment, there is a link between your hypothyroidism and risk of increased blood sugar levels and type 2 diabetes. If you have optimized your hypothyroidism treatment on Synthroid or another drug and are still struggling to lose weight, talk to your doctor about having your fasting glucose and hemoglobin A1C (HA1C) tested. If levels are high, changes to your diet and exercise, as well as type 2 diabetes medications like metformin, may help normalize your blood sugar levels and make your weight loss efforts more effective.

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