Omega-3 (EPA/DHA)

Triglyceride-lowering is bankable; everything else scales with your baseline fish intake.

Overall grade: Grade A
Last revised: Jun 8, 2026; 4
graded outcomes: 3
references listed

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A hand-written entry in Prometheus's bundled library. Its grades are the entry's own reading of the evidence, not a peer-reviewed review.

2 at grade A · 5 at grade B · 1 at grade C — 8 graded rows

What is known

Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.

Outcome	Grade	Effect size	Agreement
Triglycerides−20–30% at 2–4g/day EPA+DHA	Evidence grade A	Large	high
Cardiovascular events (high-risk)Strongest with purified high-dose EPA	Evidence grade B	Small	mixed
Depression (adjunct, EPA-heavy)≥60% EPA formulas outperform DHA-heavy	Evidence grade B	Small	mixed
Joint sorenessModest signal in inflammatory conditions	Evidence grade C	Small	low

TriglyceridesEvidence grade A
−20–30% at 2–4g/day EPA+DHA
Largehigh
Cardiovascular events (high-risk)Evidence grade B
Strongest with purified high-dose EPA
Smallmixed
Depression (adjunct, EPA-heavy)Evidence grade B
≥60% EPA formulas outperform DHA-heavy
Smallmixed
Joint sorenessEvidence grade C
Modest signal in inflammatory conditions
Smalllow

Conditions

How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.

Hypertriglyceridemia ImprovesEvidence grade A−20–30% at 2–4g/day — the bankable effectGrade A
Depression May improveEvidence grade BEPA-heavy (≥60%) formulas as an adjunct to treatmentGrade B
Rheumatoid arthritis ImprovesEvidence grade BReduced morning stiffness and NSAID useGrade B
Atrial fibrillation May worsenEvidence grade BDose-dependent AF signal at ≥4g/day in cardiovascular trialsGrade B

What is uncertain

Read off the same rows as above. Nothing here is added that the entry does not itself record.

Thin evidence: Joint soreness (grade C).
Studies disagree: Cardiovascular events (high-risk) (mixed agreement); Depression (adjunct, EPA-heavy) (mixed agreement).

EPA+DHA dose vs triglyceride drop · dose–response

Up: TG reduction %. Across: g/day. Near-linear to 4g/day; past that you're trading into the AF signal graded above.

The evidence in words

What it is

EPA and DHA — the long-chain marine omega-3s your body barely makes from plant ALA (conversion <10%). Triglyceride form absorbs meaningfully better than cheap ethyl esters, especially without a fatty meal.

What the evidence shows

Blood triglycerides drop 20–30% at 2–4g/day — as reliable as supplement effects get. Cardiovascular event reduction is real but concentrated in high-risk, low-fish-intake populations (REDUCE-IT's purified EPA). Mood support has decent evidence specifically for EPA-heavy formulas as an adjunct. Joint and general 'inflammation' claims are softer.

What to expect

Nothing subjective in most people — this is a labs-and-long-game compound. Re-test triglycerides and omega-3 index at 12 weeks; that's your ground truth, not feel.

How it is used

As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.

Maintenance: 1–2g combined EPA+DHA daily with a meal containing fat.
Triglyceride target: 2–4g/day; re-test lipids at 12 weeks.

Goes with

Zone 2 trainingThe cardio-risk stack: base volume + lipid controlEvidence grade A

Questions people ask

Fish burps?

Triglyceride-form + freezing capsules + taking with meals solves it for almost everyone; rancid oil is the other culprit — check dates.

Algae oil?

Legit DHA/EPA source, dosed equivalently. Usually pricier per gram.

Entries that share this one's tags or conditions.

CreatineThe most-studied performance supplement in existence — and it quietly helps brains too.Evidence grade A
Algae Omega-3The vegan route to EPA/DHA — the same omega-3s fish get from algae, minus the fish.Evidence grade B
Algae Omega-3 for Omega-3 indexEvidence grade B — Reliable in vegansEvidence grade B
Algae Omega-3: dosage and how to take it250–1,000 mg EPA+DHA/day.Evidence grade B

Sources

As this entry records them: title, journal and year. None carries a DOI or PubMed id, so none is linked as a verified paper. Each link searches PubMed for the title; check that what you find is what the entry describes.

1.Marine omega-3 and cardiovascular events: REDUCE-IT — N Engl J Med, 2019. Search PubMed (opens in a new tab)
2.Omega-3 fatty acids and triglycerides: dose-response meta-analysis — Am J Clin Nutr, 2020. Search PubMed (opens in a new tab)
3.EPA vs DHA in depression: network meta-analysis — Transl Psychiatry, 2019. Search PubMed (opens in a new tab)

Last revised Jun 8, 2026. A grade is this entry's reading of the evidence, not medical advice.