A “1,000 mg fish oil” softgel typically contains 300 mg of actual EPA+DHA — the other 700 mg is non-omega-3 oil. Calculator decodes label math by goal (heart, triglycerides, brain, pregnancy). Trial-derived doses, not a prescription.
Your goal
500 mg/day
Target EPA + DHA combined
2
Std fish oil softgels (~300mg EPA+DHA each)
Common products — actual EPA+DHA per serving
| Product | Total oil | EPA | DHA | EPA+DHA |
|---|---|---|---|---|
| CVS / Walmart standard fish oil (1 softgel) | 1,000 mg | 180 mg | 120 mg | 300 mg |
| Nordic Naturals Ultimate Omega (2 softgels) | 1,280 mg | 650 mg | 450 mg | 1,100 mg |
| Carlson Maximum Omega 2000 (1 softgel) | 1,000 mg | 1,250 mg | 575 mg | 2,000 mg |
| Sports Research Triple Strength (1 softgel) | 1,250 mg | 690 mg | 260 mg | 950 mg |
| Now Foods Ultra Omega-3 (1 softgel) | 1,000 mg | 500 mg | 250 mg | 750 mg |
| Lovaza (prescription) (1 capsule) | 1,000 mg | 465 mg | 375 mg | 840 mg |
| Standard krill oil (1 softgel) | 500 mg | 80 mg | 45 mg | 125 mg |
| Nordic Naturals Algae Omega (2 softgels) | 715 mg | 195 mg | 390 mg | 585 mg |
“Total oil” is the marketing number on the front of the bottle. The bottom three rows of the Supplement Facts panel tell the truth.
EPA vs DHA — they’re different molecules
- EPA (eicosapentaenoic acid): more anti-inflammatory action; stronger evidence for triglyceride reduction and mood (especially depression).
- DHA (docosahexaenoic acid): structural lipid in brain and retina; required for fetal brain development; stronger evidence for cognitive and visual function.
- For most general-health goals, the EPA:DHA ratio matters less than total EPA+DHA. Get both in a 1:1 to 3:1 range.
- For pregnancy/lactation: prioritize DHA-rich formulations (algae oil is a clean vegan source; cod liver oil adds A + D).
- For depression/mood: trials favor EPA-dominant formulations (≥60% EPA of total EPA+DHA). Saint James 2010 trial used 1g EPA + 0.5g DHA.
Trial-derived doses (the actual data)
| Goal | EPA+DHA daily | Source trial |
|---|---|---|
| General health (deficiency correction) | 250-500 mg | AHA + WHO guidelines |
| Cardiovascular event prevention | ~1,000 mg | JELIS 2007, REDUCE-IT 2018 (EPA-only icosapent 2g) |
| Triglyceride reduction (clinical) | 2,000-4,000 mg | Bays 2007, JELIS — needs Rx-grade dose |
| Depression adjunct | 1,000+ mg EPA-dominant | Sarris 2012 meta-analysis, Mocking 2016 |
| Pregnancy / DHA for fetal brain | 200-300 mg DHA | FDA/EFSA guidance; Hoge 2019 |
| ADHD adjunct (children) | 500-1,000 mg | Bloch & Qawasmi 2011 meta-analysis |
| Dry eye disease | 1,200-2,000 mg | DREAM Study 2018 — note: showed no benefit vs olive oil placebo |
| Inflammation / joint | 2,000-3,000 mg | Goldberg & Katz 2007 RA trial |
Quality + freshness checks
- Rancidity test: open a softgel and smell. Fresh fish oil has a mild ocean smell. Rotten fish oil smells like rotten fish. Discard and find a fresher product.
- Third-party testing: IFOS (International Fish Oil Standards), USP, NSF. The IFOS database lists tested products by batch.
- Form matters: triglyceride form (TG) and re-esterified TG (rTG) absorb better than ethyl ester (EE) form per Dyerberg 2010. Most premium brands use rTG.
- Refrigerate after opening: oxidation accelerates at room temp. Best brands ship in dark glass or use rosemary extract as a natural antioxidant.
- EPA+DHA per dollar: a $30 bottle of high-concentration oil often beats a $15 bottle of standard oil on a per-mg basis.
Side effects and drug interactions
- Fish burps / aftertaste: common with low-quality or oxidized oils. Refrigerate softgels, switch to enteric-coated, or try algae form.
- Bleeding risk: at doses above 3 g/day, monitor with anticoagulants (warfarin) or before surgery.
- Mercury concern: small fish (anchovy, sardine) are low in mercury. Cod liver oil and tuna oil are slightly higher.
- Vitamin A/D toxicity in cod liver oil at very high doses (over 2 tbsp/day for extended periods).
- Atrial fibrillation: high-dose omega-3 (over 4 g/day) may slightly increase AFib risk per recent meta-analyses (especially in patients with existing cardiovascular disease).
