A supplement labelled '3-6-9' can seem like the most complete choice on the shelf. Yet with omega-3, 6 and 9: do you need all three? The more useful question is which fatty acids your diet already provides, and where your diet may not provide enough. These fats have different roles in the body, different food sources and, crucially, different likelihoods of lacking in a typical UK diet.
The difference between omega-3, 6 and 9
Omega fatty acids are a family of dietary fats. The numbers refer to the position of the first double bond in their chemical structure, rather than a indicating which is "better ". All fats are not interchangeable, and each omega type behaves differently in the body.
Omega-3 and omega-6 are called essential fatty acids because the body cannot make them in sufficient amounts. They must come from food. Omega-9, on the other hand, is non-essential: the body can produce it and is also naturally present in many commonly eaten foods.
This distinction is the starting point for making a considered choice. A product containing all three is not automatically better than a focused omega-3 supplement. For many people, omega-6 and omega-9 are already readily available through everyday meals, while omega-3 is the nutrient more likely to be overlooked.
Omega-3: the fatty acid most often in focus
The two marine omega-3s, EPA and DHA, are found in oily fish and algae. DHA contributes to the maintenance of normal brain function and normal vision when consumed at 250mg of DHA is consumed daily. EPA and DHA together contribute to normal heart function with a combined daily intake of 250mg.
Oily fish such as salmon, mackerel, sardines and herring are particularly valuable sources. UK dietary guidance generally recommends two portions of fish each week, including at least one portion of oily fish. However, taste preferences, dietary choices, busy routines, cost, convenience and taste preferences mean this target is not always met.
Plant foods including flaxseed, chia seeds and walnuts provide ALA, another form of omega-3. ALA is essential, but the body converts only a small proportion into EPA and DHA - our explainer on EPA, DHA and ALA sets out the difference. This is why fish oil and algae oil supplements may be suitable for those who eat little or no oily fish. Algae oil is a particularly considered option for vegetarians and vegans, as it supplies DHA and sometimes EPA without using fish.
Omega-6: essential, but rarely scarce
Omega-6 includes linoleic acid, an essential fatty acid that contributes to the maintenance of normal blood cholesterol concentrations when consumed as part of a balanced diet. It is found in sunflower, safflower and corn oils, as well as nuts, seeds and many foods made with vegetable oils.
Most people in the UK obtain sufficient omega-6 from their usual diet. This does not make it undesirable - it remains essential - but it does mean supplementation is not routinely recommended for most people. Some specialist formulations contain gamma-linolenic acid, or GLA, from evening primrose, borage or blackcurrant seed oil. These are used for specific nutritional purposes or individual preferences rather than as a routine answer for everyone.
Omega-9: beneficial foods, not an essential supplement
Oleic acid is the best-known omega-9 fatty acid. It is abundant in olive oil, avocados, almonds, peanuts and many other plant foods associated with a Mediterranean-style way of eating. The body can make omega-9 from other fats, so there is no dietary requirement for it in the same sense as omega-3 and omega-6.
That said, choosing foods naturally rich in omega-9 can be a part of a healthy dietary pattern. Extra-virgin olive oil, for example, brings flavour and versatility to cooking and dressings. The point is that a bottle of omega-9 capsules is rarely needed to access it.
Omega-3, 6 and 9: do you need all three in a supplement?
Usually, no. You need all three types of fatty acid in the broad context of your diet, but you do not necessarily need a supplement containing all three. For those who eat fish, oily fish remains the preferred dietary source of EPA and DHA.
Some people may prefer a combined product for convenience, although this does not necessarily make it more appropriate. It can also suit those who simply want one capsule rather than several separate products.
For most people, however, a quality omega-3 product is the more targeted option if oily fish intake is low - our guide to choosing an omega-3 supplement walks through picking one. It allows you to focus on EPA and DHA without adding nutrients that are likely to be plentiful already. The label matters more than the front-of-pack promise: look for the stated amount of EPA and DHA per daily serving, rather than relying on the total fish oil quantity alone.
A 1,000mg fish oil capsule does not necessarily provide 1,000mg of EPA and DHA. The concentration can vary substantially between products. More concentrated formulations may offer higher levels of these active omega-3 fatty acids in fewer capsules, which can be more practical for a consistent routine.
How to choose an omega supplement with confidence
Your diet, preferences and health circumstances should guide the decision. Someone eating salmon or sardines regularly may not need an omega-3 supplement at all. Someone who never eats fish may prefer a fish oil or algae oil formula, depending on dietary preference.
When comparing products, consider the source, the active amount and the format. Fish oil commonly provides both EPA and DHA, while algae oil is a plant-based source that is especially useful for DHA. Krill oil naturally contains omega-3s, largely as phospholipids, and may appeal to those seeking a smaller capsule, though its EPA and DHA content should still be checked carefully - our fish oil versus krill oil comparison weighs them up.
Liquid oils can be a good choice for those who dislike swallowing capsules, while softgels are portable and simple to incorporate into a morning or evening routine. Taking an omega-3 supplement with a meal may improve comfort for some people and can help avoid a lingering fishy aftertaste.
Quality and freshness are also worth considering. Some people also consider sustainability certifications or algae-derived omega-3 products when making their choice. Omega oils are delicate and can oxidise over time, so choose products from trusted manufacturers, observe storage guidance and check the best-before date. A strong rancid smell is a sign not to use the product.
When to seek individual advice
Omega supplements are not suitable for every situation without consideration. People taking anticoagulants (such as warfarin) or antiplatelet medicines, or those with a bleeding disorder, or due to have surgery should seek advice from a healthcare professional before taking high-dose omega-3 supplements or starting a new supplement. Higher doses used to lower triglycerides should only be taken under medical supervision.
People who are pregnant or breastfeeding should seek advice on choosing an appropriate product, particularly if considering fish liver oils, which may contain vitamin A.
People with fish or shellfish allergies should check the source and allergen information closely. A marine algae oil may be preferable for some, but it is still sensible to review the full ingredient list. Supplements are designed to complement a balanced diet, not compensate for a diet that lacks variety, protein, fibre, fruit and vegetables.
Rather than choosing the broadest formula by default, begin with what is on your plate. If you're considering supplementation, explore our range of omegas and oils range including fish oil and algae-based options, and choose a product that best fits your diet and preferences.
