How To Store Your Omega – 3 Supplement?

by Norway Omega | 23/03/2021 | Blog



Scared of your fish oil supplement going bad? In this article we will explain how to properly store your omega – 3 – supplement and how to make it last as long as possible. Fish oil and krill oil contain the reactive fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential for our health and well-being. Taking such omega – 3 – supplements should be an integral part of a healthy and balanced diet and has proven to be beneficial for heart health, can decrease inflammation levels in our body, fortify our immune response and even benefit our mental health. Here we will explain how fish oil can go bad, what happens if it does and how you can check your product is fresh when you buy it.


Keep It Cool – How To Store Your Omega – 3 – Supplement

Fish oil and krill oil are the most common omega – 3 – supplements, and they can go rancid over time by reacting with oxygen. This process is called oxidation and is a chemical reaction of the fatty acids EPA and DHA with oxygen molecules in the air. EPA and DHA are so-called polyunsaturated fatty acids, which means that they contain several double bonds in their molecule. This makes them flexible and responsive to the cell and is one of the reasons why they are readily absorbed by our body. But this reactivity also makes them unstable, because the double bonds between the carbon atoms “want” to react with other molecules. The reaction with oxygen then initiates a whole series of undesirable chemical reactions in the fish oil which can produce rancidity, a fishy taste and odor and essentially makes it go off.


Delaying oxidation

Because of the nature and chemical structure of EPA and DHA, oxidation will inevitably take place at some point. What you can do however, is delay the process to make sure you can consume your supplement while it is still fresh. Because oxidation begins when the oil comes in contact with oxygen, it is important to always keep your supplement in an air-tight container. As soon as it is opened, it should be stored in the fridge because other factors such as light exposure and warm temperature can further accelerate the oxidation process. A dark, cool place is therefore the best spot to store your omega – 3 – supplement.


Capsules vs liquid fish oil

Fish oil is normally sold in two forms: as a liquid or in capsules. The capsules work as a protective shield from the oxygen in the air and can therefore prolong the shelf-life of the product. Liquid fish oil however, does go rancid faster after opening because it lacks this barrier and is directly exposed to the air and the oxygen in it. Here at Omega 3 of Norway we use high-quality gelatine capsules by the industry leader SwissCaps, to ensure the best possible consumption experience and protection for our oils.

What is the difference between fish oil and Omega-3

The Harmful Effects of Rancid Fish Oil

But what are the effects of consuming rancid or bad fish oil?


Bad smell and taste

Studies have shown that exposure to oxygen can reduce the effect of the fish oil and create a foul flavor and odor. During oxidation, new by-products like lipid peroxides, harmful aldehydes and ketones begin to form in the fish oil and give off the rancid smell and taste. These by-products can have adverse effects on our health and so diminish the positive impact of the supplement on our metabolism.


Negative side effects

Besides the bad smell and taste, consuming rancid fish oil or krill oil can have negative side effects such as heartburn and according to some studies, it can even increase the levels of “bad” cholesterol in our blood. Animal studies have further shown, that it can even lead to organ damage, inflammation and atherosclerosis for example. So always keep an eye on the expiration date when you buy a fish oil product and make sure it is fresh.


How To Check Your Fish Oil Is Fresh

As we wrote in our guide to buying omega – 3 – supplements, there are big differences in quality among the different providers of fish oil and krill oil on the market. There are essential quality indicators such as the concentration of EPA and DHA and which molecular structure they have. But once you have chosen the brand you want to buy from, make sure you check the product in store or once you receive it in the mail, to ensure that it is fresh and safe to consume.

Here is how to check if your supplement is fresh:

1)      Check the Best Before

All supplements should have an expiry date based on the production time and conditions. Consider how many capsules are included and if you take on each day, you can calculate the shortest expiry date that you can tolerate on your product. Fish oil and krill oil products normally have a shelf life of 24 months from the date they are made, but sometimes it can take a while until they arrive at the store where you buy them from.

2)      Smell the product

Like fresh seafood, fresh fish oil or krill oil should not smell fishy or rancid. If it does, this can be an indicator that it has gone off, and you should not take those capsules any more.

3)      Scan the capsule

The colour of fish oil should be clear with a golden hue. Krill oil contains the antioxidant astaxanthin which gives it a red hue, but the oil should also be clear as well. The coating of the capsule should be transparent, even and springy. If the capsule feels soft or soggy, this is an indicator that the product is not fresh any more.

4)      Taste it

A fresh product should have little to no fishy aftertaste, so make sure you toss your batch if you find that one of them tastes fishy or rancid.

5)      Quality check

Omega – 3 – supplements should contain a stabilizer which prevents it from oxidation and prolongs its shelf life. Examples for stabilizer are vitamin E or rosemary extract. Also look out for third party testing done on the oil to verity the quality standards in the production process have been met.



Omega – 3 – supplements should be stored in a cool, dry place and away from direct exposure to sunlight, as those factors accelerate the oxidation process in the oil. This process, which is a reaction of the EPA and DHA molecules with oxygen in the air, can create the breakdown of the molecules and damaging by-products.

  • store in a cool, dry, dark place
  • exposure to sunlight and oxygen can accelerate oxidation
  • make sure you buy a fresh product
  • don’t consume a supplement that looks or smells off

There are easy steps to take when buying fish oil to make sure, your product is fresh and safe. Check the expiry date and be wary of any discolouration or fishy smell or taste. Buying a subscription-based product like we offer it here at Omega 3 of Norway can be a good solution to make sure your capsules are always fresh. Avoid buying in bulk to make sure you can consume all the capsules within the recommended time frame, and before they reach their expiry date.

Head over to our shop to browse our range of products, we have both krill oil and fish oil available, in different batch sizes and subscription schemes, so there is something for everyone.