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.

READ NEXT: Are you taking your thyroid medication properly?


[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] Tirosint. 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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I appreciate every share! Thank you.

About Dana Trentini

Dana Trentini founded Hypothyroid Mom October 2012 in memory of the unborn baby she lost to hypothyroidism. This is for informational 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.


  1. Pamela Newtz says

    What is the proper way to store Levothyroxine. My 90 day supply is in a small white pill bottle with a small capsule of what I assume is a preservative. Should I leave it in the bottle. The pills are purple when they have always been white before. Is this a problem?

  2. What do you do in the summer when it is super hot? We had ac blackouts this past summer. Can you keep your thyroid meds in the refrigerator? Will the cold hurt them? If wrapped properly, the dampness might not be an issue. What about the cold?

  3. Jean Wagner says

    I accidentally spilled my bottle full of thyroxin into a damp sink. I saved and dried them on a tissue sitting out for half of a day. Are they damaged?

  4. Roy Bruder says

    The articles discuss “humidity” but no numbers are given. What level of humidity causes damage to meds?

  5. Just to take “storage” a step further, I have been keeping my Synthroid in a daily pill box with Ranitidine, 81mg Aspirin and Metropolol. I do take the Synthroid first in the morning and wait an hour before eating, and take the Aspirin and Metropolol about two hours later -and don’t take the Ranitidine until evening, but just wondering if storing them together can damage the Synthroid? Thanks…

  6. Thanks Dana. I’ve been looking everywhere to try to figure out why I have lots of symptoms back. ERFA thyroid has had shortages in Canada for the last year and I ended up taking a bottle that was about 1 year old. I wonder if that’s what’s caused my problems.


  7. Candace Prestin says

    I had ask more than one pharmacist about the degrading of my pills through the shipping method without ice and was told it was fine by all. I instinctively knew this was incorrect. Thank you for this article

  8. If I had mine in a car for three days during a move, in the heat, but moved inside to around 75 degree average, would they have been ruined that quickly? Or do you think they are still okay?

  9. Thank you for this article. Also thank you for the comment Chad.
    I have been storing my thyroid medicine in my purse. It’s been a hot summer and my purse goes everywhere with me. I noticed I was feeling hypo and just awful. I went to the Dr and she switched my medication from Nature throid to Armour. I started doing some research and when I read your comment I realized that my pills have been crumbling into pieces the last few months the. Before I had to cut them with a pill splutter or a knife. Now they crumble with just my nail. Maybe I don’t need a medication change after all.

  10. Chad Davis says

    Thanks for the article, Dana.

    For a while now I’d been storing some extra pills in a tiny little plastic case that I carried around in my pocket or in my backpack. I’d take this case over to my girlfriend’s house on the weekends so that I could leave all the pills at home safe and sound.

    I am currently adjusting some levels and am expecting ups and downs, but it was odd that every single weekend was misery for me, with a load of symptoms. Only today when I really looked hard at the pills in my case did I notice that they had become brittle and soft, breaking easily under the weight of my thumb. Of course, the ones in the bottle were hard and firm.

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