Omega-3: Fish Oil or Krill Oil? The Comparison

You're standing in front of the shelf, a large fish oil capsule in one hand and a smaller krill oil softgel with that typical reddish colour in the other – and you wonder: which one gives you more for your money? Both bring the crucial omega-3 fatty acids EPA and DHA. The difference lies in the detail: in the chemical bond, in the content per capsule, in the price and in the burping afterwards.

Answered directly: fish oil usually delivers more EPA and DHA per capsule at a lower price, krill oil binds part of the fatty acids to phospholipids, additionally contains the antioxidant astaxanthin and is often described as gentler on the stomach. What is decisive for the approved effects is not the source but the amount of EPA and DHA delivered. So always count in milligrams of EPA/DHA per daily serving, not in capsules.

The key points in brief

• Both sources deliver the omega-3 fatty acids EPA and DHA.
• Fish oil: usually triglycerides or ethyl esters, often higher content per capsule, cheaper.
• Krill oil: partly phospholipid-bound, contains astaxanthin, usually more expensive.
• DHA contributes to the maintenance of normal brain function and vision (from 250 mg DHA/day).
• EPA and DHA contribute to normal heart function (from 250 mg EPA+DHA/day).

What omega-3 does in the body

EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long-chain omega-3 fatty acids that your body incorporates into cell membranes – particularly abundantly in the brain and retina. DHA is a genuine building block there: the membranes of nerve and visual cells depend on it. That is precisely why the approved claims are so clear-cut:

• DHA contributes to the maintenance of normal brain function (from 250 mg DHA daily).
• DHA contributes to the maintenance of normal vision (from 250 mg DHA daily).
• EPA and DHA contribute to normal heart function (from 250 mg EPA+DHA daily).

These figures apply to the fatty acids themselves – whether from fish oil or krill oil. So for the choice, what counts above all is: how much EPA and DHA does the product deliver? A comparison with plant sources is offered by Omega-3: Fish Oil or Algae Oil?, and the ratio of the two fatty acids is explained in EPA and DHA: the ratio explained.

Fish oil in detail

Fish oil typically comes from oily cold-water fish such as anchovies, sardines or mackerel. EPA and DHA are usually present as triglycerides or ethyl esters, often in comparatively high content per capsule – so you often reach the amount needed for the health claims with just a few capsules. Fish oil is widespread, readily available and generally cheaper than krill oil. A decisive quality feature is purity with regard to heavy metals; good products are purified and lab-tested. Why that matters is explained in “Lab-tested” – what does it really mean?, further quality features in Recognising Omega-3 Quality: Totox, EPA/DHA Content & Purity.

Krill oil in detail

Krill oil comes from Antarctic krill, small shrimp-like crustaceans. The distinctive feature: here part of the fatty acids is bound to phospholipids instead of triglycerides. Krill oil also naturally contains astaxanthin, the red-orange plant substance that gives the oil its colour. The EPA/DHA content per capsule is often lower than with concentrated fish oil, which is why more capsules are frequently needed – and krill oil is usually more expensive. Many consider it an advantage that it less often leads to fishy burping. More on the antioxidant it contains in Astaxanthin: The Antioxidant from Microalgae.

Fish oil and krill oil in direct comparison

What research is investigating

The role of EPA and DHA as building blocks of cell membranes – particularly in the brain and retina – is well-established textbook knowledge and the basis of the approved claims. An active field of research is the question of the bioavailability of different bond forms: it is being studied whether phospholipid-bound omega-3 (krill) and triglyceride forms (fish oil) are absorbed differently well by the body. The data on this is debated and not conclusively clear. What remains clear: for the approved effects, in the end what counts is the amount of EPA and DHA absorbed, regardless of the source.

Origin and sustainability

Both oils come from the sea – and that brings the question of origin into focus. With fish oil it's worth looking at which fish species it is obtained from; small, quickly regrowing shoaling fish such as anchovies and sardines are considered more favourable for stocks than large predatory fish. With krill oil the topic is the fishing region in the Antarctic, for which there are dedicated fisheries management systems. Anyone who wants to avoid both will find, with algae oil, a purely plant-based source that delivers EPA and DHA directly from the microalga – that is, from the original starting point of the food chain, from which fish also obtain their omega-3. More on this in Covering omega-3 on a vegan diet (algae oil, ALA).

Reading and comparing content correctly

It's not the amount of oil that decides, but the actual content of EPA and DHA. On the label, look for the stated milligrams of EPA and DHA per daily serving – only this lets you judge how many capsules you need for the 250 mg DHA. A low capsule price says little if the content is low; more sensible is a comparison via the price per gram of EPA and DHA. How to read labels is shown in Reading the Label Correctly: Ingredients & Amounts. How to combine omega-3 with an antioxidant is covered in Omega-3 and Vitamin E: why they so often go together.

Freshness, rancidity and correct storage

Omega-3 fatty acids are naturally sensitive: oxygen, heat and light cause oils to oxidise over time – they turn „rancid“. A distinctly fishy, oily and unpleasant taste or smell can be a sign of this. Good products counter this with antioxidants (in krill oil naturally through astaxanthin, in fish oil often through added vitamin E) and with light-tight, airtight packaging. For you this means in practice: store cool, dark and well sealed, use up promptly after opening and pay attention to the best-before date. How to recognise rancid or expired supplements in general is covered in Shelf Life & Correct Storage of Supplements.

Intake and timing in everyday life

You best take omega-3 with a fat-containing meal, because as a fatty acid it is absorbed better together with other dietary fats. Whether morning or evening is secondary – more important is regularity, because the body's omega-3 status only builds up over weeks. Anyone prone to fishy burping can take the capsule with the largest meal of the day or opt for enteric-coated capsules. Details on timing in Omega-3: wann einnehmen and on duration in Omega-3: wie lange einnehmen.

Which source suits whom?

Fish oil is suitable for anyone looking for a high EPA/DHA content at a lower price. Krill oil is interesting if the phospholipid bond and the astaxanthin it contains are important to you, or if you react sensitively to fishy burping. Neither is suitable for vegans – the plant-based alternative is described in Flaxseed Oil or Fish Oil? Omega-3 Compared, and generally relevant is Nutrients for Vegans: Keeping an Eye on the Critical Micronutrients. With blood thinners, other medication or during pregnancy, please clarify use with a doctor.

Honestly put in perspective: what is certain and what is not

Certain: EPA and DHA are functional building blocks of the brain, retina and heart, and the approved claims apply regardless of source from defined amounts. Not conclusively clarified: whether one bond form is noticeably better utilised in practice. Anyone deciding soberly goes by the price per gram of EPA/DHA and by purity – everything else is fine-tuning.

Matching products from Scheunengut

In the Algen category you'll find algae oil as a plant-based omega-3 source, and the antioxidant contained in krill oil is available separately in the Astaxanthin category. Read on: Omega-3: wie viel am Tag, The omega-3 index explained simply, Omega-3 without fishy taste & burping, Omega-3: who is it useful for? and Welches Omega-3 kaufen? Kaufberater.

Frequently Asked Questions (FAQ)

Is krill oil better than fish oil?

Not across the board. Fish oil often delivers more EPA and DHA per capsule at a lower price, krill oil binds part to phospholipids and contains astaxanthin. For the approved effects, what counts is the amount of EPA and DHA delivered – so compare the price per gram of EPA/DHA.

How much DHA do I need for the approved effect?

The claim for normal brain function and vision applies from a daily intake of 250 mg DHA. For normal heart function, 250 mg of EPA and DHA together are needed. Check the milligram figure per daily serving on the label.

Why do you burp less fishily with krill oil?

Many users describe krill oil as gentler on the stomach. This is often associated with the phospholipid bond of the fatty acids. The experience is individual – with fish oil, enteric-coated capsules additionally help.

Are fish oil and krill oil suitable for vegans?

No, both come from animal sources. Anyone living vegan reaches for algae oil, which delivers EPA and DHA directly from the microalga – the original omega-3 source from which fish also obtain their fatty acids.