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December 12, 2022 6 min read

It's a question that many hypothyroid patients grapple with: how long should I wait to take calcium after taking my thyroid medication? 

Calcium is an essential mineral that helps build and maintain strong bones. But if you have hypothyroidism, figuring out the best time to take calcium supplements or consume calcium-rich food can be confusing. This is because calcium can interfere with the way your body absorbs thyroid hormone replacement medication like natural desiccated thyroid (NDT) and levothyroxine. But fortunately, there are ways you can take thyroid medication while still getting healthy amounts of calcium!

In this article, we'll explore how calcium interacts with your thyroid medications, when to take calcium after thyroid medication, and other tips on optimizing your medication schedule.

The purpose of using thyroid medication in the treatment of hypothyroidism

Hypothyroidism, also known as underactive thyroid, is a condition in which the thyroid gland (a small gland at the front of your neck) doesn't produce or secrete enough of the thyroid hormone that your body needs.

Doctors prescribe thyroid hormone replacement medication to treat hypothyroidism. While it's not a cure, it can help control your condition and relieve the symptoms for the rest of your life. The most commonly prescribed thyroid hormone replacement medication is levothyroxine, like Synthroid and Levoxyl. However, most hypothyroid patients prefer NDT, such as Armour Thyroid and VitaliThy. Both levothyroxine and NDT work by replacing the missing thyroid hormone that your body doesn't make enough of. These medications will help you feel more energetic as they reduce fatigue, help with weight loss, and ease other symptoms caused by hypothyroidism. They will help you lead a healthy and active life even with hypothyroidism.

However, taking hormone thyroid medication the right way is essential to ensure your body can absorb it properly. Failing to take your medication correctly can throw your thyroid hormone levels out of balance, so your symptoms won't be effectively managed.

The importance of calcium

Calcium is an essential nutrient that provides many health benefits. Not only does it help maintain strong bones of teeth, but it also plays a vital role in your body's basic functions. Your body needs calcium to move muscles, circulate blood, and release hormones. This nutrient is also important for nerve transmission.

Calcium is especially important for women since it may ease premenstrual syndrome (PMS) symptoms and reduce the risk of developing osteoporosis during menopause. Therefore, meeting the right amount of calcium is important to ensure optimal health.

In order to get the recommended amount of calcium, you can get them from calcium-rich food like dairy products, sardines, dark green vegetables, and white beans. Calcium supplements are also great options, especially if you're lactose intolerant or vegan. The most recommended forms of calcium supplements are calcium carbonate (40% elemental calcium) and calcium citrate (21% elemental calcium). 

For hypothyroid patients, it's important to note that calcium may interfere with your body's ability to absorb thyroid hormone replacement medications.

How do calcium supplements interfere with thyroid medications?

Understanding how calcium supplements interfere with thyroid medication is important, especially for women. This is because women are more likely to develop osteoporosis during menopause. Plus, hypothyroidism more commonly affects women.

When you take calcium supplements and thyroid medication together, calcium can bind to the thyroid hormone found in the medication, making those hormones inactive. This can happen whether you take calcium carbonate, calcium citrate, or calcium acetate, as well as prescribed thyroid hormone replacement or thyroid extract supplements.

One research shows that the three types of calcium supplements can reduce the absorption of levothyroxine by about 20% to 25% compared to when you take levothyroxine alone.

Can food sources of calcium interfere with thyroid hormone replacement medication?

If calcium supplements interfere with thyroid hormone treatment, can calcium-rich food affect it too?

The answer is yes, absolutely. Although the calcium levels in food aren't as high as in calcium supplements, any source of calcium may still impact thyroid hormone replacement medication.

For example, a study found that taking synthetic thyroid hormones levothyroxine together with 12 ounces of 2 percent milk had lower levels of thyroid medication in their bloodstream compared to when the medication is taken without milk.

From this research, we can see that consuming foods high in calcium can affect thyroid hormone replacement treatment, just like calcium supplements.

Here's a list of food sources of calcium you want to watch on your diet to ensure you don't eat them too close to your natural desiccated thyroid or levothyroxine dose:

  • Dairy products, such as milk, cheese, yogurt, butter

  • Almonds

  • Salmon and sardines

  • Beans and lentils

  • Leafy and dark green vegetables, such as spinach and kale

  • Calcium-fortified foods, such as cereals and orange juice

  • Figs

  • Whey protein.

Other sources of calcium you need to be aware of

Calcium supplements like calcium carbonate, calcium citrate, and calcium acetate, as well as food sources of calcium, are not the only things you need to watch out for when taking thyroid hormone replacement. Other medications and supplements containing calcium may also affect the absorption of levothyroxine and natural desiccated thyroid.


Antacids are over-the-counter medicines that neutralize stomach acid to relieve indigestion. Some people also use antacids as a calcium supplement.

This fast-acting and strong medication have a relatively high calcium carbonate content. Thus, taking antacids may interfere with how well your thyroid hormone replacement works, whether it is natural or synthetic thyroid hormones.


Multivitamins, a type of supplement containing many different vitamins and minerals, are other not-so-obvious sources of calcium. They may have calcium in the ingredient, which may interact with your thyroid hormone replacement medications.

Other medications

You may find calcium in the ingredient list of both over-the-counter and prescription medication. Of course, it can be hard to tell which one of your other medications contains calcium. One of the best ways to find out is by looking at the ingredient list or fact panel or calling your pharmacy for more information about the medications.

What happens when you take calcium and thyroid medication at the same time?

Now that you know how calcium-rich foods and calcium supplements interfere with your thyroid hormone treatment, you might be wondering what would happen when you take them at the same time.

In general, taking calcium supplements or foods with high calcium content along with thyroid hormone replacement, may significantly reduce the effectiveness of the medication. This means that you won't get the full benefit of your thyroid medication, so you'll still experience hypothyroidism symptoms. Unwanted side effects, such as digestive disorders, nausea, flatulence, and diarrhea, may even occur.


How to consume calcium when you take thyroid medication

Although calcium and thyroid medication doesn't work well together, it doesn't mean that you should cut back on either one of them. Calcium is essential for your health. Adults typically need about 1,000 to 1,200 mg of this nutrient each day. And if you have hypothyroidism, taking thyroid hormone replacement medication is essential to keep your condition under control.

The best way to prevent calcium and thyroid medication from interacting is to take them separately. The general rule is to take your calcium supplements or antacids, or eat calcium-rich foods, at least four hours before or after thyroid hormone replacement medication.

How can you make thyroid medication more effective?

Aside from separating your thyroid medication and calcium, you might want to keep the following things in mind to make your thyroid medication work more effectively.

Watch out for iron

Just like how calcium supplements interfere with the absorption of levothyroxine and natural desiccated thyroid, iron may also interact negatively. Take your iron supplements or medication containing iron at least 4 hours away from your natural and synthetic thyroid hormones.

Consider switching your thyroid medication 

If you've been taking synthetic thyroid hormones levothyroxine properly but you haven't experienced any improvements, it's probably time to consider other types of medication. One alternative you can consider is natural desiccated thyroid (NDT), such as VitaliThy. This is a natural desiccated thyroid you can buy online, which contains all the thyroid hormones your body naturally produces.

Take your thyroid medications with water

Tea, coffee, milk, juice, alcohol, and other liquids that aren't water may affect your thyroid medications.

Take your thyroid medications on an empty stomach

The American Thyroid Association also recommends taking thyroid hormone replacement on an empty stomach. This means that you shouldn't eat anything before or after taking your medication. The most common time to take prescribed thyroid hormone replacement is first thing in the morning, at least 60 minutes before breakfast. Alternatively, you might take it at night before bedtime, at least 4 hours after your last meal.

Click HERE for a full guideline on how to take your thyroid hormone replacement medications.

How long should I wait to take calcium after thyroid medication?

Final thought

If you have hypothyroidism, both calcium and thyroid hormone medications are essential for your health. This is especially true if you are a woman. Thyroid hormone medications and Desiccated Thyroid Extract supplements, such as VitaliThy, Armour Thyroid, and levothyroxine, are important to ease your symptoms. Calcium, on the other hand, is essential to lead a healthy lifestyle.

However, calcium can't be taken at the same time as your thyroid hormone replacement medication. This doesn't only apply to calcium supplements, but to other sources of calcium as well. Even small amounts of calcium, such as calcium-rich foods and medications that contain calcium, can negatively interact with your thyroid medication. Therefore, you need to take any source of calcium and thyroid medication separately, at least 4 hours away from each other.

Wojciech Majda
Wojciech Majda

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