How to read a fish oil label

Learn how to read fish oil labels, compare EPA and DHA content, spot quality markers, and store your supplements correctly. Blackmores' guide to choosing the right fish oil.

Fish oil is one of the most commonly purchased supplements in Australia, with oil supplements taken by around 6% of the population according to the Australian Bureau of Statistics’ 2023 National Nutrition and Physical Activity Survey. Yet for something so widely used, the labels can be surprisingly difficult to read. Terms like EPA, DHA, “concentrate,” and “fish oil 1000 mg” all appear on packaging and they don’t all mean the same thing.

This guide breaks down what those label numbers tell you, what to look for in a quality product, and how to store fish oil so it stays fresh.

How to read a fish oil label

The front of a fish oil bottle typically displays a large number, often 1000 mg. That figure refers to the total weight of the fish oil capsule, including all the fats it contains. The number that matters more is the combined amount of EPA and DHA, usually listed on the back panel.

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two omega-3 fatty acids with the strongest research base. They serve different roles in the body, which is why quality fish oil labels list each one separately. When comparing fish oil capsules, always check the EPA and DHA per capsule rather than the headline fish oil weight.

Serving size is another detail worth checking. Some products list EPA and DHA values per capsule, while others list them per “serving” of two or three capsules. A product showing 900 mg of omega-3 per serve may only contain 300 mg per capsule if the recommended serve is three.

What EPA and DHA numbers actually tell you

Two products can both be labelled “fish oil 1000mg” and contain very different amounts of omega-3. A standard capsule at that weight might deliver around 300mg of combined EPA and DHA. A concentrated formula at the same capsule size could deliver 900 mg. The headline number is identical, but the omega-3 content differs threefold.

This matters for daily intake. The Heart Foundation recommends 250–500 mg of combined EPA and DHA per day for general health. With a standard strength product, meeting that range may require two or three capsules. A higher concentration product can deliver the same in one. Capsule count alone is not a quality indicator: more capsules per day does not mean more benefit if the total omega-3 intake is the same.

Quality markers that matter when choosing fish oil

Purity testing: Fish can accumulate heavy metals (mercury, lead, cadmium) and environmental contaminants such as PCBs. Quality manufacturers test their products against established safety thresholds. In Australia, the TGA requires that listed medicines, including fish oil supplements, meet Good Manufacturing Practice (GMP) standards.

Freshness and oxidation: Omega-3 fatty acids break down when exposed to air, heat, or light. This process, called oxidation, changes the oil's taste and smell and may reduce its nutritional value. Quality manufacturers test each batch for oxidation and freshness before it reaches shelves. If you want to check a product's results, look for brands that publish a certificate of analysis on their website or provide one on request.

Sourcing and sustainability: Certifications such as Friend of the Sea or the Marine Stewardship Council (MSC) signal that the raw material has been responsibly harvested.

Does fish oil go off?

Yes. Fish oil has a printed shelf life, and it can degrade before that date if stored poorly. The main risk is oxidation: when the omega-3 fatty acids break down, the oil’s taste, smell, and nutritional profile all change.

An expiry date assumes recommended storage conditions. A bottle left in a hot car or on a windowsill in summer can degrade well before the printed date. Once opened, fish oil capsules are more exposed to air, so closing the lid or resealing the blister pack promptly after each dose makes a practical difference.

How to store fish oil at home

Heat, light, and air are the three factors that accelerate fish oil oxidation. Store your fish oil in a cool, dry cupboard away from the stove, oven, or direct sunlight. Avoid the bathroom, where temperature and humidity fluctuate, and avoid leaving the product in your car.

Refrigeration can help extend freshness, particularly during warmer months or in tropical climates. It is not strictly required for all products if your storage area stays consistently cool, but it’s a useful precaution. Always follow the specific storage instructions on the product label.

How to tell if fish oil has gone bad

Smell: Fresh fish oil has a mild, faintly oceanic scent. A sharp, sour, or strongly fishy smell that differs from when you first opened it suggests oxidation.

Taste: Biting into a soft capsule should reveal a relatively neutral flavour. A bitter or acrid taste is a sign of rancidity.

Appearance: For liquid fish oil, cloudiness can indicate degradation. For capsules, look for discolouration, leaking, or capsules stuck together.

If a product fails any of these checks, replace it. Rancid fish oil is unlikely to cause harm in small amounts, but it may be less effective and more likely to cause digestive discomfort.

Common fish oil myths

“Fishy aftertaste means the oil is bad.” Some aftertaste is normal, particularly when fish oil tablets are taken on an empty stomach. Taking them with food usually helps. A persistent taste that was not present when you first opened the bottle may indicate oxidation, but mild fishiness alone is not a sign of a faulty product.

“Odourless fish oil has no omega-3s.” Odourless formulations use deodorisation or enteric coatings to minimise taste and smell. These steps do not reduce the omega-3 content.

“Darker capsules are lower quality.” Capsule colour varies with the oil source, concentration process, and added ingredients like vitamin E. The EPA/DHA content and oxidation results are far more informative than visual appearance.

Choosing a fish oil that suits your needs

The decision comes down to concentration, purity, and formulation. Concentration determines how many capsules you take per day. Purity and oxidation testing confirm the oil is clean and fresh. Formulation reflects what the product is designed to deliver: some fish oils are broad-spectrum omega-3 supplements, while others include additional ingredients for specific nutritional purposes.

For readers comparing options, two products from the Blackmores range illustrate these differences. Blackmores Omega Triple Super Strength contains concentrated fish omega-3 triglycerides providing 540 mg EPA and 360 mg DHA per capsule, delivering in one capsule what three standard fish oil capsules would. Blackmores Omega Platinum combines concentrated fish omega-3 triglycerides (720 mg EPA, 480 mg DHA) with d-alpha-tocopherol (vitamin E).

Fish oil label checklist

A quick reference when comparing products online or in-store:

• Check the EPA and DHA amounts per capsule, not just the total fish oil weight.

• Compare concentration: fewer capsules per day to reach the same intake indicates a more concentrated product.
• Look for purity testing information (heavy metals, contaminants, oxidation levels).
• Check for sourcing and sustainability certifications.
• Note the expiry date and storage instructions.
• Once opened, store in a cool, dark place and reseal promptly.
• Use the smell and taste test if you suspect degradation.
• Choose a formulation that matches your nutritional needs and preferred capsule count.

Frequently asked questions

What does EPA and DHA mean on a fish oil label?

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two omega-3 fatty acids in fish oil with the strongest body of research. They serve different biological roles, so quality labels list each one separately. The combined EPA + DHA per capsule is the most useful number when comparing products.

How much EPA and DHA should I look for?

The Heart Foundation recommends 250–500 mg of combined EPA and DHA daily for general health. Check the product label to see how many capsules are needed to reach your target. For specific health considerations, speak with a healthcare professional.

How can I tell if my fish oil has gone off?

Check for a sharp or sour smell, a bitter or acrid taste when biting a capsule, or cloudiness in liquid oil. If any of these are present and differ from when you first opened the product, replace it.

What does “fish oil 1000 mg” actually mean?

It refers to the total weight of fish oil in the capsule, including all fats. A 1000 mg capsule may contain as little as 300 mg of actual EPA and DHA. Always check the omega-3 breakdown rather than the total fish oil figure.

Always read the label and follow the directions for use.

Disclaimer: This article provides general information only and is not intended to diagnose, treat, cure, or prevent any disease. The information presented is not a substitute for professional medical advice. If you have concerns about your health, please consult your GP or healthcare provider for personalised assessment and recommendations. Supplements should not replace a balanced diet.