How to Know When Fish Oil Is Oxidized

Taking dietary supplements can reduce the risk of certain diseases or ailments, and provide essential nutrients to your diet. Rich in EPA and DHA, omega-3 fatty acids from the oils of numerous fish, including salmon, herring, mackerel and tuna, fish oil supplements can benefit cardiovascular health as well as some mental disorders. One disadvantage of fish oil is its short shelf-life. Composed with high polyunsaturated fat, fish oil easily oxidizes and can turn rancid quickly.

Instructions

• 1

  Check the expiration date. Most fish oil supplements indicate expiration dates of two to three years. Fish oil is delicate and easily oxidized, so don't hesitate to test the fish oil's freshness, even if it is within the expiration date.

• 2

  Smell your fish oil capsules. Fish oil capsules should not have a rancid or strong fishy odor. If your capsules have a rancid odor, its a sign that the fish oil has started to oxidize -- or spoil -- and you should discontinue use.

• 3

  Bite or cut the capsule in half. If you're unsure of the fish oil's odor by smelling it, break open the capsule, further exposing the odor of the fish oil.