Omega-3 from algae oil – EPA and DHA directly from the source

Omega-3 fatty acids are among the most extensively studied nutrients of all. The data on EPA and DHA – the two long-chain omega-3 fatty acids – is well established for heart health, brain function and inflammation regulation. Less well known is where these fatty acids actually come from: not from fish, but from the marine algae that fish eat. Anyone who obtains omega-3 directly from microalgae goes straight to the source – and from both a biological and ecological perspective, this is more consistent than taking the detour via fish oil.

What omega-3 fatty acids are – and why EPA and DHA are particularly important

Omega-3 fatty acids are polyunsaturated fatty acids that the human body cannot produce on its own. Three forms are relevant for humans:

ALA is found in many plant-based foods, but the human body can convert it into EPA and DHA only to a very limited extent. Depending on the study, the conversion rate to EPA is below 10%, and to DHA below 1%. This conversion is therefore not reliable enough to ensure an adequate supply of long-chain omega-3 fatty acids – especially when requirements are increased.

The origin of omega-3 – algae, not fish

Fish do not naturally contain EPA and DHA – they accumulate these fatty acids by consuming microalgae. Microalgae are therefore the actual origin of marine omega-3 fatty acids. In this sense, fish oil is an intermediate product: biologically effective, but indirect.

The direct extraction of EPA and DHA from cultivated microalgae has several advantages: no fishy smell, no heavy metal contamination from the ocean, controlled production conditions and – for people who do not consume animal products – a fully plant-based source. At the same time, algae oil helps relieve pressure on overfished marine stocks.

Bioavailability of algae oil compared with fish oil

A common question is: is algae oil absorbed as well as fish oil? The answer is provided by a randomised, double-blind, placebo-controlled parallel-group study published in 2025 by the University of Kaiseraugst (International Journal of Molecular Sciences, PubMed 41096614). Over 6 and 14 weeks, 74 adults received either omega-3 supplements from microalgae or from fish oil. The result: the bioavailability of DHA and EPA from microalgae oil was statistically non-inferior to fish oil. Algae oil is therefore an equivalent, direct source.

What research shows about EPA and DHA

Heart health

The evidence for EPA and DHA in heart health is exceptionally well documented among nutrients. A meta-analysis of 38 randomised controlled trials with 149,051 participants (eClinicalMedicine, 2021, PMC 8413259) showed that omega-3 supplementation statistically significantly reduced cardiovascular mortality, non-fatal myocardial infarction and coronary events. An updated systematic review with meta-regression (Clinical and Translational Discovery, 2025, literature search up to August 2025) confirms positive effects – with a stronger signal in people with existing cardiovascular risk and at higher dosages.

Important limitation: the effects are more consistent in high-risk patients than in the general population. EPA monotherapy in pharmacological dosage showed stronger cardiovascular effects than the EPA+DHA combination in individual studies – this difference has not yet been conclusively clarified.

Brain and nervous system

DHA is the most abundant omega-3 fatty acid in the brain and in the retina of the eye. It is a structural component of neuronal cell membranes and essential for the normal development and function of the central nervous system. In the EU, DHA is supported by an authorised health claim: DHA contributes to the maintenance of normal brain function – with a daily intake of 250 mg. The same applies to vision: DHA contributes to the maintenance of normal vision.

Inflammation regulation

EPA is a precursor for anti-inflammatory eicosanoids such as prostaglandins, leukotrienes and resolvins. Unlike arachidonic acid – the most important omega-6 fatty acid – EPA promotes the formation of mediators that help resolve inflammatory processes rather than intensify them. The omega-6 to omega-3 ratio in the Western diet is now around 15:1 to 20:1 – far from the evolutionarily assumed ratio of 4:1 or lower.

Dry eye and tear film

A meta-analysis of 19 RCTs (Journal of Clinical Medicine, 2023, PMC 10672334) showed that omega-3 supplementation significantly improves tear film stability and symptoms of dry eye – with a stronger effect at a high EPA proportion and longer intake duration. However, the large DREAM study (NEJM, 2018) found no significant difference compared with placebo. The evidence is positive, but not uniform.

Who particularly benefits from omega-3 supplementation

• People who rarely eat oily fish – salmon, mackerel, herring and sardines are the richest natural EPA/DHA sources; those who rarely consume them hardly cover their requirements through diet
• People with a plant-based diet – vegans have been shown to have lower omega-3 index values; algae oil is the only fully plant-based EPA/DHA source
• Pregnant and breastfeeding women – DHA is essential for the child’s brain and eye development; requirements increase significantly during pregnancy
• People with increased cardiovascular risk – this is where the evidence for additional benefit is strongest

Conclusion

EPA and DHA are the biologically active omega-3 fatty acids – and their natural source is microalgae, not fish. Fish is merely an intermediate storage source. Anyone who obtains omega-3 directly from algae oil receives the same bioavailability as from fish oil – as shown by a current randomised study from 2025 – without the disadvantages: no fishy smell, no heavy metals, no animal suffering, lower environmental impact.

The evidence for EPA and DHA is particularly well established for heart health, brain function and vision. Anyone who rarely eats fish, follows a plant-based diet or belongs to a risk group has good reasons to check their own omega-3 supply.

This article is for general information only and does not replace medical advice. Dietary supplements are not a substitute for a balanced and varied diet.