Fatty acids
Find omega-3 from fish oil, krill and algae, plus omega-6 oils, MCT and flaxseed. We explain what the EPA and DHA numbers on a label really mean, which forms absorb best and who each type suits. Our guidance below helps you compare strengths.Read more →
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Choosing between omega-3, omega-6 and plant oils
Fatty acids are the building blocks of the fats in your food. Two of them your body cannot make at all: alpha-linolenic acid (ALA), an omega-3 from seeds and nuts, and linoleic acid, an omega-6 from vegetable oils. The long-chain omega-3s EPA and DHA can be built from ALA, but only in very small amounts. That is why oily fish, fish oil and algae get most of the attention, and why the largest part of this collection sits around them.
The number on the front of the bottle is not the dose
A bottle that says 1000 mg is usually telling you the amount of fish oil, not the amount of omega-3. Turn it over and add up the EPA and DHA per daily serving. A standard 1000 mg fish oil capsule often supplies around 180 mg EPA and 120 mg DHA. EPA and DHA contribute to the normal function of the heart at 250 mg a day, so one product reaches that in a single capsule while another needs three. The Omega-3 pages group the higher-strength options.
Forms differ more than the price tag suggests
When fish oil is concentrated, the omega-3 is usually turned into an ethyl ester, a form your body has to convert back before it can use it. Re-esterified triglyceride oils skip that step and absorb better, but they cost more to make. Taken with a fatty meal, an ethyl ester closes much of that gap, so it stays a sensible budget choice if you always take it with food.
- Fish oil: most EPA and DHA per capsule, usually from small fish such as anchovies and sardines.
- Algae oil: the original source of DHA, plant-based, often DHA-forward with less EPA.
- Krill oil: omega-3 attached to phospholipids, but fewer milligrams per capsule.
- Cod liver oil: omega-3 plus vitamins A and D, so keep an eye on your vitamin A total.
- Seed oils: flaxseed for ALA, evening primrose and borage for GLA.
Omega-6 is a smaller part of the picture, because most UK diets already supply plenty of linoleic acid through cooking oils and processed food. People still choose the omega-6 oils for GLA from evening primrose or borage, which behaves differently in the body from ordinary linoleic acid.
How we choose the oils in this range
We look at three things: the form, the dose and whether a combination makes sense. We prefer triglyceride and re-esterified triglyceride fish oils and algae oils, because they absorb well without needing a fatty meal alongside. We ask for EPA and DHA per serving to be printed clearly, not hidden behind a total oil figure. Unspecified cheap concentrates without freshness data do not make it in. We buy directly from the brands, our compliance team checks every product before it goes live, and independent labs spot-check batches. You can read how we select our brands.
Who this suits, and what to expect
This collection fits you if you rarely eat oily fish, follow a plant-based diet, or want a steady daily intake without cooking fish twice a week. If you already eat two portions of fish a week, one of them oily, you are meeting UK dietary advice and a supplement adds less. Levels of EPA and DHA in your blood shift slowly, so give any product two to three months of daily use before you judge it. If you want a set amount rather than a general oil, the concentrated EPA and DHA products make that easier to plan.
Frequently asked questions
What are essential fatty acids?
Fatty acids are the parts that make up fats. Two are called essential because the body cannot make them: alpha-linolenic acid (ALA), an omega-3 found in flaxseed, walnuts and rapeseed oil, and linoleic acid, an omega-6 found in most vegetable oils. The long-chain omega-3s EPA and DHA come mainly from oily fish and algae. Your body can make some EPA and DHA from ALA, but the conversion is slow and limited, so many people take them directly.
How much EPA and DHA is a normal daily amount?
The amount depends on what you want from the product. Approved claims each come with their own intake condition, and the higher ones sit well above what a single capsule delivers.
| Purpose | Daily EPA and DHA |
|---|---|
| Normal heart function | 250 mg |
| Normal blood pressure or normal blood triglyceride levels | 2 g to 4 g |
| Supplemental intake with no safety concern for adults | up to 5 g |
Most daily supplements are built around the 250 mg level.
Which form of omega-3 should I choose?
Start with your diet and your budget, then look at the form on the back of the pack.
| Form | Absorption | Best suited for |
|---|---|---|
| Re-esterified triglyceride | Very good | High strength, fewer capsules |
| Natural triglyceride | Good | Lower strength, closest to fish |
| Ethyl ester | Lower, better with food | Budget, taken with a meal |
| Algae oil | Good | Vegans, DHA-led intake |
| Krill oil | Good | Small doses, phospholipids |
If the label only says concentrate, it is usually an ethyl ester.
When is the best time to take a fatty acid supplement?
Take it with a meal that contains some fat. These are oils, and a little dietary fat helps you absorb them, which matters most for ethyl ester fish oils. The time of day makes almost no difference, so pick the meal you never skip. Taking omega-3 on an empty stomach is the most common cause of fishy burps and mild nausea. Keeping the bottle cool and closed also helps, since these oils turn rancid when exposed to air and warmth.
Do I need an omega-6 supplement as well?
Usually not for linoleic acid. Most UK diets already contain plenty of it through sunflower and rapeseed oils, spreads and processed food, so extra intake adds little. The reason people buy omega-6 oils is different: evening primrose and borage supply GLA, a fatty acid that only appears in small amounts elsewhere. If that is what you are after, check the GLA milligrams on the label rather than the total oil weight, because the two numbers are far apart.
Is algae oil as good as fish oil?
For DHA, yes. Fish do not make omega-3 themselves, they get it from algae, so algae oil goes straight to the original source. It is grown in closed tanks, which keeps it free of ocean pollutants, and it suits anyone avoiding fish. The catch is the amount: many algae oils are DHA-forward with modest EPA, and capsules tend to carry fewer milligrams, so you may need two. Compare it with other vegan supplements on EPA and DHA per serving, not per capsule.
Can I take omega-3 during pregnancy?
DHA is often chosen during pregnancy, but the type of product matters. UK guidance is specific about vitamin A, which is why cod liver oil and other fish liver oils are not suitable.
| NHS guidance | Amount |
|---|---|
| Fish per week, adults | At least 2 portions, 1 oily |
| Portion size | About 140 g |
| Oily fish if pregnant or trying to conceive | No more than 2 portions |
| Vitamin A, food and supplements combined | No more than 1.5 mg per day |
The NHS advises avoiding vitamin A supplements, including cod liver oil, in pregnancy.
Should I be careful with high doses or with blood-thinning medication?
Yes, and this is worth reading before you buy a high-strength oil. Fish oil can affect how easily your blood clots, so if you take anticoagulants such as warfarin, or you have surgery planned, speak to your GP first. Very high daily amounts are also a different category from a general daily supplement: EFSA considers supplemental intakes of up to 5 g EPA and DHA a day safe for adults, but there is no reason to go near that for everyday use. Standard products of 250 mg to 1000 mg cover most people.
