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Heat's Effect on Supplements in the Mail -- Woman receiving a package


Many vitamins and other supplements can degrade faster and lose effectiveness when exposed to excessive heat, light, oxygen in the air, or humidity. Even under ideal conditions, vitamins normally degrade over time, but this process is accelerated by poor storage conditions. Although overly degraded supplements may not be unsafe to take, you won't receive the amount of ingredient stated on the label and may not get the desired effect.

See the full answer for how different types of supplements are affected by the environment, particularly heat, and what you should do to protect them. Get the Full Answer >>

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June 25, 2021

I live in the Philippines where the temperature is usually 30 degrees C and humidity is 70. What is the best place to store vitamins B, C, E and D and other supplements?
June 25, 2021

It depends on what the conditions are in your home. If those are the conditions at home, consider storing supplements in a refrigerator and not leaving bottles open or out too long.

June 26, 2021

Thank you.

June 17, 2020

I try to not buy online any supplements or foods during the hot months of summer. But with prescriptions, it irks me that most health insurance plans require patients to get prescriptions by mail and then severely limit the amount that can be kept at home. This means that many of us are receiving heat-damaged prescriptions in warm weather because of health-insurance directives or requirements. What really gets me is when the patient is taking a drug that can't really be abused, such as thyroid medication, and yet the 90-day limitation and inability to refill until down to about 10 pills or fewer means we cannot control for heat damage in shipments. And if you actually have a life and are going to be on travel or have something unexpected come up, that at-home prescription limitation practically ties you down to waiting for the mail.

June 17, 2020

Last summer I bought several bottles of vegan omega-3 oil supplements by mail order. Each bottle arrived with the tablets melted together into a big lump, with the vegan fish oil leaking out and smelling rancid. It was completely unusable -- a waste of about $30 for each ruined bottle. So now I stock up on supplements (and chocolate chips :) ) in the spring, before the weather heats up, so that I won't need to order them again until autumn.

September 18, 2019

I'm confused. In the above write-up, CL states to only refrigerate if the label indicates to do so, and yet in its write-up for fish oil capsules, it seems to recommend refrigerating the fish oil capsules (and especially liquid).

We just started taking fish oil capsules and are storing them in the refrigerator to prevent rancidity. If the label doesn't state that refrigeration is needed for our fish oil capsules, should we ignore the CL suggestion in its Keep It Fresh section of the fish oil review to "If possible, refrigeration can help prolong freshness..."?
September 18, 2019

Refrigeration may not be necessary with fish oil softgels (which are protected from oxygen) but it can prolong shelf-life and may also reduce fishy burps. So, no downside, and some potential upside, to refrigerating fish oil softgels. Definitely refrigerate bottled fish oil.

September 15, 2019

My astaxanthin arrived on a hot day and spent several hours outside before I could retrieve it. Is it safe to consume or should I return it and ask for it to be re-shipped with a cold pack?
September 17, 2019

Hi Deborah - Like most compounds, when exposed to oxygen and heat, astaxanthin can degrade over time. However, the effect of heat is minimized when oxygen is minimized, such as in a softgel -- which is how most astaxanthin is sold -- which keeps it pretty stable. Unless the softgels were melted, the product is probably not compromised (see the ConsumerTips section of the Astaxanthin Supplements Review

September 17, 2019

Thank you!

April 26, 2018

If a desiccant pack was not included in the bottle, is it safe to add one?
April 26, 2018

Hi Stephen - Yes, it should be safe to add one.

April 26, 2018

Thank you!
April 26, 2018

You're welcome Stephen!

March 25, 2018

I get most of my Rx drugs and supplements by mail, but never during hot months or winter freezes. I keep out only what I need, then store the rest in double-sealed plastic bags with desiccant packs at 40F in my fridge. To avoid condensation I always bring them back to room temp before opening a sealed bag.
I’m hoping to extend their life beyond the use-by-date. I commented on this back in 2016.
The desiccant I’m using for this is: Stack-On Safe 'N Dry Spad-60 packets by DESICCARE, INC. These are a combination silica jell & activated charcoal desiccant pack, and are available as 10 packs for about $12 by ordering them from Wal-Mart.
I’m also putting these in my dry hot cereals and beans to protect from yeast or mold.

July 19, 2017

I have been in the practice of buying locally during the summer months to avoid exposure of supplements to heat while being shipped to my home. Today when I spoke with a local vitamin store retailer(in central North Carolina) about their "ship-to-store" option, he said those products were shipped the same as they are to your home, running the same risk of heat exposure. Then I asked if their store inventory products were protected from heat during shipment. He said they used to be via refrigerated trucks, but were no longer. So, my shopping locally is now not much of a guarantee of whether what I buy has been exposed to heat. I guess I'll have to get more organized to buy enough of a supply in the weather friendly months to get through the extreme hot/cold seasons.

July 2, 2018

My son works at Whole Foods Market and he said most of their stuff including supplements is delivered by refrigerated truck.

June 2, 2017

"If you order supplements by mail, try not to order during excessively hot periods."

Could you provide some guidelines for what you consider "excessively hot"?
June 2, 2017

90 degrees Farenheit and above.

June 28, 2018

I received a bottle of probiotics at 3 PM today. It had been on the UPS truck all day and felt warm. I inserted my kitchen instant read thermometer through the paper safety seal and got a reading of 90.5 F degrees. No surprise I guess because it's summer and outside temperatures are in the high 90's.
June 29, 2018

Hi Robert - Thank you for sharing this. Where did you purchase the probiotic from, and, did they offer the option of sending it refrigerated?

July 2, 2018

Amazon said requesting a cold pack wasn't an option. They offered to overnight another bottle via UPS to see if it would arrive at a lower temp. I received it at 10:45 am and it was at 85.5 degrees, so 5 degrees cooler. Nature's Way assured me the product would still be good if it reached 90 degrees for a time because the capsules are oversupplied, but suggested I now keep it in the fridge to prevent further compromise. The bottle says to store at 75 degrees or cooler, or refrigerate.

July 10, 2016

Supplements and prescription medicines are often packed with a desiccant. Once the bottle is opened, is there any benefit leaving it in the bottle until the pills are finished?
July 11, 2016

Hi Daniel - Yes, as noted in the answer, if a desiccant packet was included, keep it in the bottle.

May 29, 2016

Considering the high cost of both Supplements and Prescription drugs obtaining the longest possible shelf life is very important.
Years ago, I learned that our Federal Government stockpiles vast quantities of Rx drugs in caves, and that they undertook a project of determining if the use-by-date could be extended--and exactly how. Unfortunately they never shared their findings with the American people.
They have the resources and ability to test the actual effectiveness of drugs after long storage; I do not.
However, based on what it likely or logically true, I've started storing my supplements and Rx drugs under refrigeration at 40F in a sealed quart jar with a combination silica jell & activated charcoal desiccant pack inside it. I was able to obtain 10 packs for about $12 by ordering them from Wal-Mart. The Stack-On Safe 'N Dry Spad-60 packets have a color changing indicator, and can be recharged by heating at 200F in an oven for 6 hours. They're made by DESICCARE, INC.
I may eventually to into freezer at 0F.
I'd appreciate your comments about this.

June 1, 2016

Dear Smitty - What you are currently doing may be more than you need to, but would not seem to do any harm. When you remove the container, let it get back to room temperature before opening, or you may get condensation inside the container. Storing at below freezing could potentially be a problem, as it could affect the chemical structure of products.

March 28, 2018

It would seem wise to store unopened and rarely used products in the refrigerator and then keep them at room temperature when using. I live overseas part of the time, and I keep several boxes in the vegetables compartment untouched for months. Should I also close them in a plastic bag?
March 28, 2018

Hi Helen - While it could not hurt to put them in a bag, there is little humidity in a refrigerator to be concerned about.

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