Omega-3: what it does, its benefits and how to choose the right supplement
Introduction
Have you heard of omega-3 but aren't quite sure what it does, or whether it's worth taking? You're not alone. Omega-3 is one of the most studied supplements in the world — and also one of the most misunderstood. Some people take it without knowing why; others avoid it because they're not sure whether it's really necessary.
In this article we explain, based on scientific evidence, what omega-3 is, what its real benefits are, who can benefit from supplementation and how to tell a quality product apart from one that is, in practice, little more than low-cost oil in a capsule.
No exaggerated promises. Just what the science says.
What omega-3 is and why our body needs it
Omega-3 is a group of essential polyunsaturated fatty acids — in other words, the human body cannot produce them in sufficient quantities on its own. We need to obtain them through our diet or, when diet alone is not enough, through supplementation.
The three main ones are:
- EPA (eicosapentaenoic acid) — with the greatest impact on inflammatory processes and cardiovascular health
- DHA (docosahexaenoic acid) — essential for brain function and eye health
- ALA (alpha-linolenic acid) — found in plant sources such as flaxseed and walnuts; the body converts it into EPA and DHA, but only to a very limited extent
The main dietary sources of EPA and DHA are oily fish such as salmon, sardines, mackerel and tuna. For those who don't eat fish regularly, supplementation can be an effective way to ensure adequate levels.
Evidence-based benefits of omega-3
Omega-3 is one of the supplements with the most scientific literature available. It is no exaggeration to say that its benefits are among the best documented in nutrition. Here are the most relevant:
Cardiovascular health
EPA and DHA contribute to the maintenance of normal blood triglyceride levels — one of the health claims approved by EFSA (the European Food Safety Authority). Studies published in the Journal of the American Heart Association associate regular omega-3 intake with a reduction in cardiovascular risk in populations with elevated triglycerides.
Cognitive function and brain health
DHA is a structural component of the brain — it accounts for around 97% of the omega-3 fatty acids present in the cerebral cortex. EFSA recognises that DHA contributes to the maintenance of normal brain function in adults (250 mg/day of DHA).
Eye health
DHA also contributes to the maintenance of normal vision, an EFSA-approved claim with a daily intake of 250 mg.
Inflammatory response
EPA plays a relevant role in regulating inflammatory processes. Although inflammation is a natural and necessary response of the body, chronic low-grade inflammation is associated with various health conditions. Omega-3 may help to modulate this process — not eliminate it, but contribute to a healthier balance.
Important note: Always consult a doctor or nutritionist before starting any supplementation, especially if you take anticoagulants or have cardiovascular health conditions.
To find out more, see the Examine.com database on omega-3 and the reviews available on PubMed.
How to choose a quality omega-3 supplement
Not all omega-3 supplements are the same. There are significant differences in concentration, chemical form and purity that make all the difference to the results. Here's what to check:
1. EPA and DHA concentration
Many products state "1000 mg fish oil" on the packaging — but what matters is the total amount of EPA + DHA. A standard fish oil may contain only 300 mg of active omega-3 per capsule; a concentrated product may contain 700 mg or more. Read the label carefully.
2. Chemical form: triglycerides vs. ethyl esters
Omega-3 can come in two main forms:
- Triglycerides (TG): the natural form, with better documented absorption
- Ethyl esters (EE): the most common and economical form, but with lower bioavailability on an empty stomach
If you want to maximise absorption, opt for triglyceride-form formulas — such as NOW Foods Super Omega EPA Fish Oil.
3. Purity and certifications
Look for products with third-party certification (IFOS, NSF or equivalent) that guarantees the absence of heavy metals, dioxins and PCBs — common contaminants in fish. A quality product will be transparent about this.
4. EPA:DHA ratio
Depending on your goal, the ideal ratio varies:
| Goal | Recommended ratio |
|---|---|
| Cardiovascular health and inflammation | Higher proportion of EPA |
| Cognitive health and mood | Higher proportion of DHA |
| General health and eyes | Balanced proportion |
Who can benefit most from supplementation
Omega-3 supplementation may be particularly relevant for:
- People who don't eat fish 2 to 3 times a week
- Adults with elevated triglycerides (always under medical supervision)
- People with preventive cardiovascular health goals
- Those who do regular physical exercise and want to support recovery
- Older adults concerned about long-term cognitive health
Those following a vegetarian or vegan diet can opt for algal omega-3 (from algae), which provides DHA and EPA without the need for fish.
FAQ — Frequently asked questions about omega-3
What is the recommended daily dose of omega-3?
For general health, EFSA recognises the benefits of 250 mg/day of combined EPA + DHA. For specific goals such as elevated triglycerides, the doses studied range from 2 to 4 g/day of EPA + DHA — always under the supervision of a healthcare professional.
Is it better to take omega-3 in the morning or at night?
The time of day makes little difference. What matters most is taking it with a meal that contains fat, which significantly improves absorption. Choose whichever time is easiest to keep up as a consistent habit.
Does omega-3 make you put on weight?
No. Omega-3 is a fat, but at supplemental doses (1 to 4 g/day) its calorie contribution is minimal. More importantly, omega-3 has no association with weight gain in the available studies. What may vary is how the body uses fats — but that is not the same as weight gain.
Does omega-3 have side effects?
At normal doses, omega-3 is well tolerated by most people. The most common side effects are mild and gastrointestinal: fishy breath, reflux or digestive discomfort. Taking it with a meal and choosing quality (non-oxidised) products reduces these effects. At high doses, it may have a mild anticoagulant effect — relevant for those taking certain medications.
Conclusion
Omega-3 is, with good reason, one of the supplements most recommended by healthcare professionals. Its benefits for cardiovascular health, brain function and the inflammatory response have solid scientific backing — and supplementation makes sense for those who cannot obtain sufficient amounts from diet alone.
But product quality matters. EPA and DHA concentration, chemical form and purity are the factors that set an effective supplement apart from one that does little more than drain your wallet.
At Nutri9, our selection focuses on exactly these criteria. If you want to start or improve your omega-3 supplementation, explore our options and make an informed choice.
Our featured product: Super Omega EPA Fish Oil — NOW Foods