logoThe People's Perspective on Medicine

Calcium Blocks Thyroid Absorption

Calcium Blocks Thyroid Absorption
Thyroid levothyroxine

Q. I was diagnosed as hypothyroid last year and my doctor said that once I started taking Synthroid I would feel great. Well, I don’t.

I am health conscious and walk at least a mile every day. I take lots of vitamins and make sure to take 1000 mg of calcium daily. Despite my efforts I don’t have much energy. I have not been able to lose weight and I am feeling very depressed. I asked my doctor if a higher dose of Synthroid would help but she said it could weaken my bones.

Help! A friend says you have a guide. How can I get it? Are there any herbs that help thyroid?

A. Your calcium supplement could be part of the problem. Researchers have found that calcium interferes with thyroid absorption just as iron, magnesium, zinc, selenium and aluminum hydroxide can. Levothyroxine (Synthroid) should be taken at least two hours before these minerals.

There are actually a large number of things that can interfere with proper absorption and function of a thyroid supplement. Coffee, fiber and medications such as strong acid suppressing drugs (proton pump inhibitors like Prilosec, Prevacid and Nexium) may all impact levothyroxine absorption (International Journal of Endocrinology, online, June 7, 2015). Other drugs that may interact with thyroid supplements include the cholesterol lowering agent cholestyramine and the osteoporosis medication raloxifene (Evista).

When to Take Levothyroxine:

There is growing evidence that taking levothyroxine before bedtime may enhance absorption. A review of the available research concluded:

Based on the available literature, bedtime administration of levothyroxine is an option for patients with hypothyroidism who want to avoid taking their medication with food.” (American Journal of Health-System Pharmacy, March, 2015).

Here is a link to our recently revised Guide to Thyroid Hormones, which describes symptoms, treatment and interpretation of test results for thyroid problems. It also has a complete analysis of new research demonstrating that some people require both T3 as well as T4 (levothyroxine) to feel well.

We know that conventional wisdom maintains that levothyroxine alone is adequate for virtually all people with hypothyroidism. That may not be true for people who have a hard time converting T4 to its active form, T3, due to their genetic makeup. Learn the details of this fascinating new research in our guide.

Herbs for Hypothyroidism?

There have been relatively few good studies of herbs for treating hypothyroidism. One botanical medicine from the Ayurvedic tradition may hold promise, however. Ashwagandha (Withania somnifera) may improve free T4 levels and mood in people with hypothyroidism and depression (Journal of Ayurvedic and Integrative Medicine, Oct-Dec, 2014).

If your thyroid dose is adjusted properly, you may be less depressed. That could help your energy level, ability to exercise and weight control program. If taking your levothyroxine on an empty stomach (one hour before meals or four hours after eating) does not solve the problem, you may want to explore the possibility that you are not converting T4 to T3 adequately. Our guide will help you and your doctor analyze this potential challenge.

Rate this article
star-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-emptystar-fullstar-empty
4.7- 58 ratings
About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
Thyroid Hormones
$4.99

What symptoms signal thyroid trouble? This extensive guide to Thyroid Hormones has critical info on testing, treatment, and side effects.

Thyroid Hormones
Join over 150,000 Subscribers at The People's Pharmacy

We're empowering you to make wise decisions about your own health, by providing you with essential health information about both medical and alternative treatment options.