EPA, DHA and DPA: three omega-3s, three jobs
Fish-oil labels shout about two molecules — EPA and DHA. But the omega-3 family has a quieter third member, DPA, that sits right between them, comes mostly from red meat, and may be doing more than anyone gave it credit for.
The 60-Second Answer
EPA, DHA and DPA are the three long-chain omega-3 fatty acids. EPA (20 carbons) is the body's main anti-inflammatory omega-3. DHA (22 carbons) is structural — it builds the brain and retina. DPA (22 carbons, 5 double bonds) is the overlooked middle child: a metabolic reservoir that converts readily back to EPA, comes largely from red meat, and shows unique effects on blood-vessel repair. Aim for 250–500 mg/day of combined EPA+DHA from oily fish or a quality supplement — most people fall far short.
Three molecules, one family
Omega-3s share a first double bond at the third carbon, but they are not interchangeable. ALA (alpha-linolenic acid, 18:3n-3) is the plant "parent" found in flax, chia and walnuts. The body slowly elongates and desaturates it along a chain: ALA → EPA (20:5n-3) → DPA (22:5n-3) → DHA (22:6n-3).[1][2]
Notice DPA's structure — 22 carbons like DHA, but only 5 double bonds like EPA. It is literally the bridge between the two.
The omega-3 family: where DPA sits
Chain length and degree of unsaturation
DPA has 22 carbons like DHA but 5 double bonds like EPA — structurally the bridge between the two. Source: NIH ODS; standard lipid biochemistry[1].
EPA — the inflammation regulator
EPA is a poor substrate for the potent pro-inflammatory eicosanoids the body makes from arachidonic acid, so displacing arachidonic acid with EPA shifts the balance toward less inflammation and less clotting.[1] EPA is also the precursor for specialised "resolvin" mediators that actively switch inflammation off.
In mood research, supplements that are EPA-dominant have shown a signal for reducing depressive symptoms that DHA-dominant formulas have not consistently matched.[3]
DHA — the structural one
DHA is the omega-3 the body chooses to build with. It is the dominant omega-3 in the grey matter of the brain and in the retina, where it is essential for neuronal membranes and vision.[1][2]
Because it sits at the end of the pathway, DHA can also be "retro-converted" backward into EPA — an estimated 7–14% of a DHA dose reappears as EPA.[2] The reverse (making DHA from EPA) is far less efficient in humans.
DPA — the overlooked middle child
DPA (docosapentaenoic acid, 22:5n-3) is the least talked-about long-chain omega-3, largely because it is rarely listed on labels and is under-studied.[4][5] Three things make it interesting.
First, it is a reservoir: DPA retro-converts readily to EPA across many tissues but converts only poorly forward to DHA, so it behaves like a stored, on-demand source of EPA.[4][6] Second, in laboratory work DPA showed roughly ten-fold greater ability than EPA to stimulate endothelial-cell migration — the process behind blood-vessel repair and wound healing — and was more potent than either EPA or DHA at inhibiting platelet aggregation.[4] Third, its main dietary source is not fish but red meat, which is why it is essentially absent from plant-based diets and under-dosed in typical fish oil.[5][7]
What's really in a 1,000 mg fish-oil capsule (standard 18/12)
mg per 1000 mg softgel
A typical 18/12 fish-oil softgel is mostly EPA and DHA; DPA is present in small amounts (~20–50 mg) and usually isn't printed on the label. Source: typical fish-oil concentrations; DPA reviews (Kaur 2011; Byelashov 2015)[4][5].
Why you can't just make them from flax
This is the practical catch with plant omega-3s. Conversion of ALA down the chain is limited: in men roughly 8% of dietary ALA becomes EPA and only 0–4% becomes DHA; in women the figures are higher — about 21% to EPA and 9% to DHA — a difference attributed to oestrogen.[2] Overall, less than 15% of ALA is converted to the long-chain forms.[1]
So flax, chia and walnuts are a useful bonus, not a reliable substitute for pre-formed marine omega-3s — especially for men. The same "what the label says versus what the body does" problem shows up elsewhere in the supplement aisle; our review of vitamin K2 (MK-7) and arterial health is a good companion read.
How much, and from where
Most guidelines converge on about 250–500 mg/day of combined EPA+DHA for general health, with roughly 1 g/day used in cardiovascular contexts.[1] Yet US adults average only about 90 mg/day of EPA+DHA — far below that target.[1] Every extra 1 g/day of long-chain omega-3 lowers triglycerides by about 5.9 mg/dL, more in people who start high.[1]
Two servings of oily fish a week (salmon, herring, mackerel, sardines) deliver EPA, DHA and some DPA together; a concentrated fish-oil or algae supplement fills the gap when fish intake is low. If you want to know where you actually stand, the cardiovascular biomarker panel is the place to start.
What this means in practice
- Eat oily fish (salmon, herring, mackerel, sardines) about twice a week — it delivers all three omega-3s together, including DPA.[5]
- If you supplement, read the actual EPA+DHA milligrams, not the "1000 mg fish oil" headline; aim for 250–500 mg/day combined (higher only with a clinician's guidance if triglycerides are high).[1]
- Flax and chia give ALA, which converts poorly — a bonus, not a replacement for marine omega-3s, especially for men.[2]
- DPA comes largely from red meat; strict plant-based eaters get almost none and depend on limited retro-conversion — an algae-based EPA/DHA supplement is the practical route.[7]
- An omega-3 index blood test reflects your true status better than counting label numbers.[8]
Frequently asked questions
Is DPA better than EPA or DHA?
No single omega-3 is “best” — they do different jobs. DPA acts as a reservoir that tops up EPA and shows some unique effects on blood-vessel repair, but it is less studied than EPA and DHA.
Can I get enough omega-3 from flaxseed?
Not reliably. Plant ALA converts poorly to the long-chain forms (in men under ~8% to EPA and 0–4% to DHA), so flax is a supplement to, not a substitute for, fish or algae oil.
Does my fish oil contain DPA?
Usually a small amount — roughly 20–50 mg per 1000 mg capsule — and it is often not listed separately on the label.
How much EPA and DHA should I take?
About 250–500 mg/day combined for general health. Higher therapeutic doses for elevated triglycerides should be guided by a clinician.
Is DPA vegan?
No. The main dietary source is red meat, so vegans get almost none and rely on limited conversion from algae-derived EPA/DHA.
References
- [1]NIH Office of Dietary Supplements. Omega-3 Fatty Acids — Health Professional Fact Sheet.
- [2]Linus Pauling Institute, Oregon State University. Essential Fatty Acids.
- [3]Everlywell (clinician-reviewed summary). EPA vs. DHA in Fish Oil and Omega-3 Fatty Acids.
- [4]Kaur G, Cameron-Smith D, Garg M, Sinclair AJ. Docosapentaenoic acid (22:5n-3): A review of its biological effects. Prog Lipid Res. 2011;50(1):28-34.
- [5]Byelashov OA, Sinclair AJ, Kaur G. Dietary sources, current intakes, and nutritional role of omega-3 docosapentaenoic acid. Lipid Technol. 2015;27(4):79-82.
- [6]Drouin G, Rioux V, Legrand P. The n-3 docosapentaenoic acid (DPA): A new player in the n-3 long chain polyunsaturated fatty acid family. Biochimie. 2019;159:36-48.
- [7]Richter CK, et al. n-3 Docosapentaenoic Acid Intake and Relationship with Plasma Long-Chain n-3 Fatty Acid Concentrations in the United States: NHANES 2003–2014. Nutrients. 2019.
- [8]Comparative effects of dietary n-3 DPA, DHA and EPA on plasma lipid parameters, oxidative status and fatty-acid tissue composition. Prostaglandins Leukot Essent Fatty Acids. 2018.