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Choosing the Best Fish Oil

Fish Oil and Hot Weather

written by Vin Kutty

comments 18 comments

best fish oil supplement

Heat and fish oil don’t go well together

Every year, in July and August, I get dozens of emails asking me if fish oil supplements will go bad if shipped in hot weather.

The answer is: well, it depends.

It depends on two things:

  1. How hot it is
  2. Whether your bottle of fish oil will sit in your hot mailbox for hours

As a rule, if it gets hotter than 100 degrees at our shipping offices in California, we will not ship. We will wait a couple of days until it cools. We also have a Michigan ware that ships during those delays.

Of course, you’ll get an email from us letting you know if there is a delay.

US Postal Service

We ship using US Postal Service and as long as the product is under their care, we have found that products don’t get too hot.

The problems start when the bottle of fish oil is left in a hot mailbox.

Or if there is no one to receive the shipment or if there is no shade outside your front door. Even if it is 90 degrees, and the mailman can leave the shipment in a shady spot on your porch, the pills will be fine.

Heat and oxygen are enemies of Omega-3

OmegaVia is produced in an oxygen-free environment and after manufacturing, the gelatin capsule keeps oxygen from reaching the oil in the pills. But there is not much we can do to prevent heat damage if the bottle is left in a hot mailbox for a few hours.

A few hours in a hot mailbox can not only make the oil rancid, it can melt the gelatin capsule.

Once the gelatin melts, oil leaks out and makes a gooey mess. If this happens to your product, discard the bottle. Once the fish oil is exposed to air, rancidity (oxidation) sets in very quickly.

An Easy Trick!

There is an easy way to tell if your pills have been heat abused or melted even before you open the bottle – shake the bottle! If you hear fish oil pills rattling in the bottle, all is well. If you hear a thunk-thunk, the pills have melted and clumped together. It may not have leaked yet, but the damage may have already begun if you hear a thunk instead of a rattle.

When you shake the bottle…

  • Rattle is good.
  • Thunk is bad.
  • Sloshing is really bad.

Melting and clumping are very rare.

What typically happens during a heat wave is that the pills get close to 85 or 90 degrees for short periods of time – a few hours. This won’t melt the pills or make your omega-3 rancid. No harm done.

Unless you live in Phoenix or Palm Springs where the temperature can reach 110 in the shade. We worry about that. We don’t like to ship to Phoenix between June and September.

We don’t worry about Florida – humidity does not affect gelatin melting point or Omega-3 oxidation.
Shipping fish oil supplements to Phoenix in Summer is a bad idea.

How ’bout ice-packs?

We don’t use ice packs and styrofoam boxes because of the high costs and the limited cooling time it offers.

Here are some practical options:

1. Get your Summer stock…in Spring!
Many of our AutoShip customers get their entire summer supply of OmegaVia shipped to them in May. Or April.

2. Track your shipment. If the weather is extra-hot, request tracking numbers for your packages so you know which day to expect your shipment, so it does not sit in the mailbox.

3. Different shipping address. Have the package delivered to your work place, a neighbor, your church etc., where someone can bring the fish oil inside from the heat.



Join the conversation

  1. Hello,

    I ordered liquid fish oil, Nordic Naturals complete omega 3, 6, 9. The fish oil came via UPS Ground. It was placed in a truck and shipped to my house in Phoenix, AZ. Today’s high was about 100 degrees. My shipment was placed for a couple of hours by my door step. Upon inspection of the fish oil, the bottle was very warm (Hot).

    My question is, is the fish oil now expired? Has it lost it’s quality?

    I quickly placed it in the refrigerator and have not yet opened it’s seal.


    Also, jamaican black castor oil and emu oil were delivered to me in the mail box and it sat there for like 6 hours in the hot weather, can these be rancid too? Please e-mail me, thanks.

    • Hi Sam – It is possible that the oil was compromised in the heat. You may wish to contact Nordic Naturals about the next steps. If the oil smells fishy, you will know if it was ruined or not.

      Emu oil (from the bird) and Castor oil are both sources of monounsaturated fats. These fats are less likely to go rancid with a few hours of heat. But if it smells bad, it could be the trace amounts of Omega-3 present going bad. May I suggest you try olive oil or avocado oil instead as a source of monounsaturated fats?

  2. Hi,
    I live in u.a.e when temp. Is somewhere near 50 degree.
    I left my pills in tge car, and after 8 hours i remmember that they might go off.
    When i checked them, they where like stiked to eachother, but there was no bad smell coming out of them…
    I put tgem in tge fridg… But all i want to know is that any possibility that the components are damaged or it still can be taken??

    • Hi Saleh – 50 degrees C is very hot – I imagine that it gets incredibly hot in cars. I would discard the product and buy new pills.

  3. My soft gel fish oil is leaking even though I have been keeping them in the frig. They have not been sitting in heat, I can’t figure out how to stop it. What can I do?

    • Hi Marie – if you’re talking about OmegaVia products, please call our customer service line and they will send you a replacement. But if you’re talking about another brand, then I suggest tossing the bottle and replacing it with a new one. Once you have one leaker in the bottle, then all the pills will get coated with the leaked oil. This also increases the rancidity and the smell. Best just to toss the bottle and start new.

  4. Hi my krill oil was delivered and onysilbox about two hours it was 100 degrees the jar was not to touch pills not melted when cit one open did not smell rancid just fishy goodbor not?

    • Hi Kenna – hard to say without testing the product, but probably good if you’re not getting a rancid odor.

  5. Thank you for your honesty. Most companies I’ve contacted will not admit to this. I live in AZ and it reached 117 today. Today I bought Carlson cod liver oil from a local Vitamin Shoppe store hoping that it had been shipped to them before it got really hot. I have to say I don’t know the difference between a rancid odor and fish odor. Can you explain what the difference is? I will keep your website in mind when I can order again.


    • Hi Paula – it is hard to explain what stinky fish oil smells like! But once you bite into a fish oil pill, you will know. Especially if it is old and rancid. But even fresh fish oil has a very slight fishy odor.

    • Hi Amr – there is no specific temperature. Cooler is better. But room temperature is OK. You will have problems with warm temperature is combined with time. The longer it is exposed to hot weather, the shorter the life of the product.

  6. Hi,

    I just found a bottle of OmegaVia in my closet that I must have left at my parents from a couple of years ago since I have been living somewhere else. The expiry was only 23rd May 2017, so about 3 months ago. I know sometimes expiry dates are conservative and there is usually a bit of leeway, would they be alright to take still? Thanks

    • Hi Hayden – there should be plenty of Omeag-3 in the capsules. However, after the expiration point, the oxidation (rancidity) levels can be higher than what we’d like. There is no harm in taking the pills, but personally, I’d toss it and get fresher product.

  7. i leave boxes outside for 3 days , because of the virus /high risk. i thought there were only 3 items of clothing in this ups box and when i opened it, i found optivite vitamins and omega 3 soft gels. it’s in the 90’s here in myrtle beach, so i guess they are very bad.

    • Hi Suzie – I would not leave fish oil pills in the sun in the summer time. If they were in the shade, you may be OK. But if they were in the sun, it probably got a little cooked. I would discard and buy new stuff. You may want to consider putting some rubbing alcohol in a spray bottle and spraying down the boxes right after delivery. Then bring them in to the garage or someplace where you can leave them along for as long as you want. Although the rubbing alcohol spray will essentially kill all virus exposed to the alcohol.

  8. Hello Vin, I live in St. Geroge Utah, and the temp today is 100.
    I recently ordered Zinc and Quercetin bottles, and it was sitting in front of porch like two hours before I pick up. It was under shade, but I am just worried. I know there are not fish oil type of supplement, but are these be ok?

    • Hi Potatohunter – yes, zinc being a mineral can handle the heat. I would not worry about Quercetin either, as it is a dried herbal. Neither of the active ingredients are going to be damaged at 100-120 degrees.

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