Improper storage could be destroying your thyroid medication

Improper storage could be destroying your thyroid medication


It’s pounding.

It won’t stop.


I need more sleep.

I’m so tired.

The heels of my feet.

They’re cracking and so dry.

Step on the scale.

Oh no.

5 extra pounds in 12 days.

What’s happening to me?

What does improper storage do to your thyroid medication? I found out last sweltering hot and humid summer in New York City.

For years I’ve had my thyroid medication mailed to me from a pharmacy just outside New York City. They are reliable and fast and I’ve loved having my medication appear in the mail exactly when I need them. I’ve always paid the extra cost of mailing my medication overnight but this one particular time last summer I decided to save a few bucks and have them put in the regular mail that would take a couple of days to arrive.

I received my new prescription in the mail. I remember that week had been a real scorcher. If you’ve ever been to New York in July or August, you know the heat and humidity are unreal. The subway platforms underground have no air conditioning and you sweat your ass off waiting for your train.

It didn’t cross my mind that the heat and humidity could be a problem for my thyroid medication. I was trying to save a few bucks on shipping, after all.

I took my medication every day, just as usual. One by one my old hypothyroidism symptoms (that I had kissed goodbye for years, and yes I thank my lucky stars every day!!!) started reappearing. Of course, being Hypothyroid Mom, I went through all the different possible reasons why I was unusually unwell, but improper storage of my medication was not on my list.

Was there a problem with this particular batch of thyroid medication? Had the manufacturer reported a problem? Was my hypothyroidism suddenly getting worse?

Mistakes in Storage May Alter Medication

Then I came across an article that appeared in The New York Times, “Mistakes in Storage May Alter Medication”.[1] That’s when I learned that heat can destroy medications. According to Skye McKennon, clinical assistant professor at the University of Washington School of Pharmacy,

Thyroid, birth control and other medicines that contain hormones are especially susceptible to temperature changes. These are often protein-based, and when protein gets hot it changes properties. “Think of an egg,” Dr. McKennon said. “When it gets hot, it cooks.”

I had requested regular mail delivery for my medication. Right? My thyroid medication was transported for days, probably in unairconditioned trucks or warehouses, until it reached my destination. The humidity and heat were at a high that month.

I called my pharmacy for a new refill and paid extra for same-day delivery. Within days my hypothyroidism symptoms started disappearing and within weeks I was back to feeling great again.

Improper Storage of Thyroid Medication

That incident faded from my thoughts. I figured it was an unusual circumstance that didn’t happen often to patients, until I came across the study “Refractory Hypothyroidism Due to Improper Storage of Levothyroxine Tablets” published in Frontiers in Endocrinology on July 10, 2017.[2]

Patients on Levothyroxine therapy referred to three Italian outpatient Clinics of Endocrinology between January 2013 and December 2015 for refractory hypothyroidism (a condition characterized by persistently abnormal serum TSH levels despite levothyroxine therapy) were investigated for levothyroxine tablet exposure to humidity, light, and high temperature. Careful patients’ history taking disclosed that these eight patients stored their levothyroxine tablets inappropriately. Normalization of serum TSH levels was obtained in all cases by simply recommending to store the tablets away from heat, light, and humidity.

How many of my Hypothyroid Mom readers are storing their thyroid medication improperly?

I took a closer look at the article. Here below you’ll find the ways in which the participants used to improperly store their levothyroxine tablets exposing them to heat, humidity and/or light. Could you be improperly storing your thyroid medication in similar ways?

Patient 1 in a drug cabinet of water closet, above the heating unit, about 40 cm from both the shower and Jacuzzi

Patient 2 in a drawer of the kitchen room, around 20 cm from the burners and oven

Patient 3 in a water closet where mold originating from the roof and balcony was evident

Patient 4 (previously undergone thyroidectomy for euthyroid benign multinodular goiter) in a transparent glass placed on the nightstand, under both the night light and the abat jour (lampshade), since 6:00 p.m. until 8:00 a.m.

Patient 5 in a drug cabinet of the water closet, above the heating unit

Patient 6 in a drawer of the kitchen room, around 40 cm from the burners and oven

Patient 7 in a transparent glass placed in the kitchen room, close to the sunlight coming through the window, since 2:00 p.m. until 6:00 a.m.

Patient 8 in a transparent glass placed on the nightstand, close to the heating unit and the light from a night bulb, since 11:00 p.m. until 8:00 a.m.

Improper Storage Can Happen With Every Thyroid Medication Brand

I decided to take a look at the prescribing information, specifically the storage directions, for a few different brands of thyroid medications. Turns out the importance of proper storage is not limited to levothyroxine tablets. If you are wondering why there are different types of thyroid medications that you’ve never heard about, please read my article Which is the best thyroid drug for hypothyroidism?


Synthroid is a popular synthetic T4 levothyroxine tablet made by AbbVie. The full prescribing information includes “Storage Condition”:[3]

Store at 25°C (77°F); excursions permitted to 15° to 30° C (59° to 86° F).

SYNTHROID tablets should be protected from light and moisture.


Tirosint is a gel cap form of synthetic T4 levothyroxine, not a tablet. This appears on the website under “HOW SUPPLIED/STORAGE AND HANDLING”:[4]

Store at 25°C (77°F); excursions permitted to 15°-30°C (59°-86°F) [See USP Controlled Room Temperature]. TIROSINT capsules should be protected from heat, light and moisture.

Do not remove the individual capsules from blister packaging until ready to use.


Cytomel is a brand of synthetic T3 thyroid hormone made by Pfizer. This appears in the “How Supplied/Storage and Handling” section:[5]

Store between 15° and 30°C (59° and 86°F)

Nature-throid & WP Thyroid

Nature-throid and WP Thyroid are two brands of natural desiccated thyroid containing both T4 and T3 from pig thyroid made by RLC Labs. They both have the same storage direction:[6,7]

Store at controlled room temperature; 15°-30°C (59°-86°F)
Dispense in tight, light-resistant containers as defined in the USP/NF Rx Only.

Armour Thyroid

Armour Thyroid is another brand of natural desiccated thyroid made by Allergan. The Full prescribing information includes storage instructions:[8]

Store in a tight container protected from light and moisture. Store between 15°C and 30°C (59°F and 86°F).

Thyroid by ERFA

The Canadian company ERFA makes a brand of natural desiccated thyroid simply called Thyroid.[9]

Store at controlled room temperature 15 to 30°C.

What an important lesson. Always, always read the full prescribing information for every medication prescribed, including thyroid medications. Following the storage directions can mean all the difference between feeling well and feeling like the walking dead.


  1. Walecia Konrad: Mistakes in Storage May Alter Medication. The New York Times August 15, 2011. Retrieved from
  2. Benvenga, S. et al. Refractory Hypothyroidism Due to Improper Storage of Levothyroxine Tablets. Front. Endocrinol. 10 July 2017;8:155.doi: 10.3389/fendo.2017.00155
  3. Synthroid. Storage Conditions. Retrieved from
  4. Tyrosint. How Supplied/Storage and Handling. Retrieved from
  5. Pfizer. Cytomel. How Supplied/Storage and Handling. Retrieved from
  6. Nature-thyroid. Full Prescribing Information. Retrieved from
  7. WP Thyroid. Full Prescribing Information. Retrieved from
  8. Allergan. Armour Thyroid. Full Prescribing Information. Retrieved from\
  9. ERFA. Thyroid. Retrieved from

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About Dana Trentini

Who knew that little butterfly-shaped thyroid gland at the base of my neck could affect my life so completely? I founded Hypothyroid Mom in memory of the unborn baby I lost to hypothyroidism. Winner of two 2014 WEGO Health Activist Awards: Health Activist Hero & Best In Show Twitter. Hypothyroid Mom is for information purposes only and should not be considered a substitute for consulting your physician regarding medical advice pertaining to your health. Hypothyroid Mom includes Affiliate links including the Amazon Services LLC Associates Program. Connect with me on Google+

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