Marine omega-3s (EPA, DHA) support cardiovascular, brain, and visual health. They come from either fatty fish and fish oils, or algae oils derived from cultivated microalgae. This comparison synthesizes the key points for choosing in practice, at equal performance, based on your goals, budget, and preferences.
EPA/DHA: real efficacy by source
Fatty fish directly provide EPA and DHA, two active and bioavailable forms useful for the heart and brain, in line with consumption guidelines for EPA/DHA described by health authorities (EPA and DHA).
Algae oils mainly provide DHA (amounts of EPA vary by strain and formulation), and constitute a non-animal source endorsed by reference syntheses on forms and sources of omega-3s (DHA, forms and sources).
- Common guideline: aim for approximately 250 mg/day of EPA + DHA in total (diet ± supplement) according to recommended intakes (recommended intakes).
- Specific goals (triglycerides, prescriptions): require medical supervision.
Fish don't "make" EPA/DHA: they accumulate them by consuming marine microalgae. Algae oils therefore access this source directly, useful when you don't consume fish.
Key efficacy points:
- Fish/fish oil: balanced EPA + DHA profiles, practical for covering the overall guideline.
- Algae oil: emphasis on DHA (brain, vision); useful when the priority goal is DHA (e.g., pregnancy/breastfeeding), or in vegetarian/vegan diets (DHA — roles and uses).
Purity and contaminants: what controls say
Fish can concentrate heavy metals (e.g., methylmercury) and persistent organic pollutants (dioxins, PCBs) along the food chain. Authorities continuously assess these risks and issue consumption and safety guidelines (heavy metals – mercury, dioxins and PCBs).
Quality fish oils undergo refining/purification steps to reduce these contaminants before marketing; choosing products tested for contaminants and compliant with standards is essential (tested for contaminants).
Conversely, algae oils are produced from cultures in controlled environments, which limits exposure to marine contaminants and helps control oxidation during manufacturing. Final quality remains dependent on good practices (cold chain, antioxidants, packaging, expiration date).
High doses of marine omega-3s can potentiate the effect of anticoagulants/antiplatelets. Stay under medical advice if you're treated for a cardiovascular disorder, and respect safety guidelines (drug interactions).
EFSA indicates a prudence threshold of 3 g/day of marine omega-3s beyond which the risk of bleeding increases; don't exceed these doses without supervision (safety threshold).
Cost per serving: comparing correctly
The right metric for comparing heterogeneous products is the price per 250 mg of EPA + DHA (daily guideline), rather than per capsule/unit.
In practice:
- "Standard" fish oils are often more economical to reach 250–500 mg/day of EPA + DHA.
- Algae oils (DHA) are generally more expensive at equivalent quantity, but relevant if targeting mainly DHA (e.g., pregnancy/breastfeeding) or if avoiding marine products.
Identify for 1 serving: the mg of EPA, the mg of DHA, and the total EPA + DHA. Then compare the price per 250 mg EPA + DHA. Check the date, the form (triglycerides, ethyl esters), and the addition of antioxidants (e.g., vitamin E).
| # | Source | EPA (typical profile) | DHA (typical profile) | Purity/controls | Cost $/250 mg EPA+DHA | Note |
|---|---|---|---|---|---|---|
| 1 | Standard fish oil (TG) | Moderate | Moderate | Refining + compliance | Rather low | Good cost/guideline ratio |
| 2 | Concentrated fish oil (TG/EE) | High | High | Advanced refining | Medium to high | Fewer capsules for same guideline |
| 3 | Algae oil DHA | Low to variable | High | Controlled culture | Rather high | Ideal if DHA priority (pregnancy, plant-based) |
| 4 | Algae oil EPA+DHA (rare formulations) | Variable | Moderate to high | Controlled culture | High | Plant-based alternative when EPA required |
For whom: concrete use cases
- Omnivore: alternate fatty fish 2×/week and, if needed, a tested EPA + DHA product to reach recommended intakes (recommended intakes).
- Vegetarian/vegan: aim for a DHA-rich algae oil to secure intake, possibly supplemented with an EPA source depending on goals.
- Pregnancy/breastfeeding: DHA supports brain and vision development; strengthen intake while staying within safety thresholds (role of DHA).
- Fish allergy / ethical preference: favor an algae oil.
- Therapeutic goals (triglycerides): require a prescription (high doses) and medical supervision.
- EPA + DHA per serving (aim for 250 mg/day minimum, depending on goal); 2) Quality: product tested for contaminants; 3) Date/antioxidants; 4) Form (TG/EE); 5) Budget: compare in $/250 mg.
In brief
- Both sources are effective if total EPA + DHA intake is reached.
- Fish/fish oil: more economical, balanced EPA + DHA profiles.
- Algae oil: plant-based and clean, DHA high; often more expensive at equivalent quantity.
- Choose based on goal (EPA + DHA vs DHA priority), dietary constraints, quality, and budget.
Sources
- NIH Office of Dietary Supplements — Omega-3 Fatty Acids (Health Professional Fact Sheet): https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/
- FAO/WHO — Fats and fatty acids in human nutrition (Report): https://www.fao.org/3/i1953e/i1953e.pdf
- EFSA — Dietary reference values for fats: https://www.efsa.europa.eu/en/efsajournal/pub/4253
- EFSA — DHA/omega-3: safety threshold and precautions: https://www.efsa.europa.eu/en/press/news/120727
- EFSA — Mercury (methylmercury): https://www.efsa.europa.eu/en/topics/topic/mercury
- EFSA — Dioxins and PCBs: https://www.efsa.europa.eu/en/topics/topic/dioxins-and-pcbs
