Omega-3: what the evidence actually shows

declining omega-3 — attention cooling after large mixed/null trials

Reviewer and governance status are shown on each atomic claim below.

What it is

Omega-3 is tracked as a health intervention in this evidence graph. Also known as: fish oil, EPA/DHA.

Studied forms and doses

No form-specific catalog record is available. This does not mean all forms are equivalent.

heart health: 1–2 g/day EPA/DHA; form not reported.
inflammation: 1–3 g/day; form not reported.
mood: 1–2 g EPA; form not reported.
joint health: 2–3 g EPA+DHA/day; form not reported.
skin: not standardized; form not reported.
blood sugar: varies; EPA/DHA ratio appears to matter; form not reported.

Mechanisms

Mechanistic plausibility is context, not proof that a clinical outcome improves.

No structured mechanism is recorded.

⚠ Safety in context

seriouswith Warfarin: High-dose omega-3 with warfarin may increase bleeding risk.

Products and verification

No product label snapshot is mapped in this released catalog. Ingredient evidence does not establish any bottle’s identity, potency, purity, availability, or value.

Evidence by outcome

heart healthgrade Bmoderate certainty— modest cardiovascular benefit; large recent trials were mixed

inflammationgrade Bmoderate certainty— lowers inflammation markers in the blood; bigger doses have a bigger effect

joint healthgrade Bmoderate certainty— reduces joint tenderness / morning stiffness in rheumatoid arthritis

blood sugargrade Bmoderate certainty— Meta-analysis in type 2 diabetes: results for omega-3 on glucose control were mixed and, overall, no consistent improvement in glycemic control was demonstrated. The authors note the EPA/DHA ratio and early intervention may modify effects — a subgroup signal, not a general glucose benefit.

moodgrade Cmoderate certainty— small benefit for depressive symptoms, clearest with higher-EPA formulations

skingrade Dvery-low certainty— Narrative review: omega-3 fatty acids have plausible dermatological roles (skin barrier, inflammation modulation, photoprotection), but controlled clinical evidence that supplementation improves specific skin outcomes is limited and preliminary.

People say · Evidence shows

“Fish oil prevents heart attacks”

aheadlargemarketing claim

What it probably doesn't do

Omega-3 for skin — Grade D, Narrative review: omega-3 fatty acids have plausible dermatological roles (skin barrier, inflammation modulation, photoprotection), but controlled clinical evidence that supplementation improves specific skin outcomes is limited and preliminary..

Grade history

2026-07-16B → BSource correction by Claude (b2 garbage-source correction): replaced an off-topic search-fallback source (published before the pump's topica details →
2026-07-16C → CMerged additional source by Claude (gold-standard provenance sweep): a distinct, independently-verified paper ("ω-3 Fatty acids for major de details →
2026-07-16B → BCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-35914448] details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-37028202] details →
2026-07-16B → BCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid:29387889] details →

full change history

Re-review cadence: every 12 months (Grade A/B) · next scheduled by 2027-07-16 · methodology v1.

By outcome — the money pages

Compare

sources: PMID:29387889 · PMID:35914448 · PMID:17335973 · PMID:26431431 · PMID:37028202 · PMID:26936905 · PMID:32463305

Cite this page

Citation is encouraged. The proposed reuse license is CC-BY-4.0; status: pending-governance-ratification.

Plain-text citation

Substrate. Omega-3: what the evidence actually shows. https://evidencebased.info/interventions/omega-3. Updated 2026-07-16.

BibTeX

@misc{substrate_ointerventionsomega3,
  author = {Substrate editorial},
  title  = {Omega-3: what the evidence actually shows},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/omega-3},
  note   = {evidencebased.info}
}