Medical Disclaimer: Omega-3 supplements are generally safe. High doses (>3g EPA/DHA) may increase bleeding risk (especially with anticoagulants), affect blood sugar, and cause GI upset. Consult a healthcare provider if you’re on blood thinners, have a bleeding disorder, or are undergoing surgery.
Key Takeaways
- EPA and DHA are not interchangeable. EPA = anti-inflammatory, cardiovascular, mood. DHA = brain, eyes, fetal development. Ratio matters for your goal.
- Form determines absorption. rTG (re-esterified triglyceride) > TG (natural triglyceride) > PL (phospholipid/krill) > EE (ethyl ester). EE is poorly absorbed without high-fat meal.
- Oxidation is the silent killer. Rancid fish oil = pro-inflammatory, defeats purpose. TOTOX <10 (ideally <5). Demand CoA.
- Dose by EPA+DHA, not “fish oil.” 1g fish oil ≠1g EPA/DHA. Typical 1000mg softgel = 300mg EPA/DHA (30% concentration).
- Vegan? Algal oil = DHA-rich, sustainable. EPA:DHA ~1:2. Look for life’s™OMEGA or Almega®PL.
EPA vs. DHA: Different Jobs
| Function | EPA (Eicosapentaenoic) | DHA (Docosahexaenoic) |
|---|---|---|
| Primary Role | Anti-inflammatory signaling (resolvins, protectins) | Structural: brain (30% of fatty acids), retina (50%), sperm |
| Cardiovascular | ↓ Triglycerides, ↓ platelet aggregation, ↑ HDL, endothelial function | Membrane fluidity, heart rate variability |
| Mental Health | Depression (↑ EPA/DHA > 60% EPA), bipolar adjunct | Cognitive development, aging brain |
| Pregnancy/Infant | Preterm birth prevention | Fetal brain/eye development (3rd trimester + first 2 years) |
| Joints/Inflammation | ↓ PGE2, ↓ LTB4, ↓ CRP, ↓ TNF-α | Membrane resolution |
| Typical Ratio in Fish | ~1.5:1 to 2:1 (EPA:DHA) | ~1:1.5 to 1:2 (varies by species) |
Target Ratios by Goal
| Goal | EPA:DHA Ratio | Total EPA+DHA/Day | Example Product Profile |
|---|---|---|---|
| General Health / Maintenance | ~1.5:1 to 2:1 | 500–1000mg | Standard fish oil (180/120 or 300/200 per 1g) |
| Cardiovascular / Triglycerides | 2:1 to 3:1 (High EPA) | 2000–4000mg | Vascepa® (Rx, 96% EPA) / High-EPA concentrates |
| Depression / Mood | >60% EPA (EPA ≥ DHA) | 1000–2000mg | EPA-rich (e.g., 700 EPA / 200 DHA per serving) |
| Pregnancy / Infant Development | 1:2 (High DHA) | 300mg DHA min (+ EPA) | Prenatal DHA (200–500mg DHA) |
| Cognitive / Aging Brain | 1:1 to 1:2 (Balanced/High DHA) | 1000–2000mg | Balanced or DHA-rich |
| Joint Inflammation / Autoimmune | High EPA (2:1 to 4:1) | 2000–3000mg | High-EPA concentrate |
| ADHD (Children) | >60% EPA | 500–1000mg EPA+DHA | EPA-rich liquid (easier dosing) |
Forms: Absorption Hierarchy
| Form | Chemistry | Absorption (vs. TG) | Pros | Cons | Best For |
|---|---|---|---|---|---|
| rTG (Re-esterified TG) | EE → back to TG (enzymatic) | 124–140% | High absorption, high concentration possible, stable | Costlier than EE | Best overall |
| TG (Natural Triglyceride) | As in fish (sn-2 position) | 100% (reference) | Natural, good absorption | Lower concentration (~30%), larger pills | Whole food purists |
| PL (Phospholipid / Krill) | Phosphatidylcholine-bound | ~100–115% | No fish burps, astaxanthin antioxidant | Low EPA/DHA per pill (40–80mg), expensive, sustainability concerns | Burp-sensitive, low dose needs |
| EE (Ethyl Ester) | Ethanol backbone (synthetic) | ~70–85% (needs high-fat meal) | Cheap, high concentration possible | Poor absorption without fat, oxidizes faster, GI upset | Avoid |
| FFA (Free Fatty Acid) | Unbound (e.g., Vascepa®) | >140% | Highest absorption, prescription | Rx only, unstable | Medical use |
Rule: If label doesn’t state “triglyceride form” or “rTG” → assume EE (cheapest, worst absorption). rTG is worth the premium.
Oxidation: The Quality Metric That Matters Most
| Metric | What It Measures | GOED Standard | IFOS 5-Star | What to Demand |
|---|---|---|---|---|
| Peroxide Value (PV) | Primary oxidation (hydroperoxides) | <5 meq/kg | <2.5 meq/kg | <5 meq/kg |
| Anisidine Value (AV) | Secondary oxidation (aldehydes) | <20 | <10 | <10 |
| TOTOX (2×PV + AV) | Total oxidation | <26 | <10 | <10 (ideally <5) |
TOTOX <10 = fresh. TOTOX 10–26 = acceptable but degrading. TOTOX >26 = rancid. Most store brands: 15–30. Always request lot-specific CoA.
Contaminants: Heavy Metals, PCBs, Dioxins
- Mercury: Neurotoxin. GOED: <0.1 ppm. Molecular distillation removes.
- Lead: Neurotoxin. GOED: <0.1 ppm.
- PCBs (Polychlorinated biphenyls): Carcinogen. GOED: <0.09 ppm (90 ppb). IFOS: <45 ppb.
- Dioxins/Furans: Carcinogen. WHO TEQ <1 pg/g.
- Arsenic: GOED: <0.1 ppm.
Molecular distillation + carbon filtration = standard for quality brands. Krill oil naturally lower (shorter food chain).
Brand Rankings (Tested, rTG Preferred, TOTOX <10)
High EPA/DHA Concentrate (rTG, IFOS 5-Star / ConsumerLab)
| Brand | Product | Form | EPA/DHA per Serving | Ratio | Cost/Day (1g) | Testing |
|---|---|---|---|---|---|---|
| Nordic Naturals | ProOmega 2000 | rTG | 1125mg (725 EPA / 400 DHA) | ~1.8:1 | $0.90 | IFOS 5-Star, CoA |
| Nordic Naturals | ProEPA 1000 | rTG | 1000mg (900 EPA / 100 DHA) | 9:1 | $0.80 | IFOS 5-Star, CoA |
| Carlson | The Very Finest Fish Oil | TG | 800mg (400 EPA / 300 DHA) | 1.3:1 | $0.40 | IFOS, ConsumerLab |
| Nutrigold | Triple Strength Omega-3 Gold | rTG | 1000mg (750 EPA / 250 DHA) | 3:1 | $0.50 | ConsumerLab, IFOS |
| Life Extension | Super Omega-3 | rTG | 1200mg (720 EPA / 480 DHA) | 1.5:1 | $0.55 | IFOS 5-Star, CoA |
| Sports Research | Triple Strength | rTG | 1000mg (690 EPA / 310 DHA) | ~2.2:1 | $0.35 | ConsumerLab, IFOS |
High DHA (Pregnancy, Cognitive)
| Brand | Product | Form | DHA/EPA per Serving | Ratio | Cost/Day |
|---|---|---|---|---|---|
| Nordic Naturals | Prenatal DHA | rTG | 480 DHA / 205 EPA | 1:2.3 | $0.70 |
| Carlson | Mother’s DHA | TG | 500 DHA / 100 EPA | 1:5 | $0.45 |
| MegaFood | Baby & Me 2 DHA | rTG | 300 DHA / 50 EPA | 1:6 | $0.60 |
Vegan / Algal Oil (DHA-Rich)
| Brand | Product | Source | DHA/EPA per Serving | Cost/Day |
|---|---|---|---|---|
| Nordic Naturals | Algae Omega | Schizochytrium | 195 DHA / 105 EPA | $0.80 |
| DEVA | Vegan DHA-EPA | Schizochytrium | 200 DHA / 100 EPA | $0.30 |
| OmegaQuant | Omega-3 Index Test + Algal Oil | Schizochytrium | 300 DHA / 150 EPA | $0.50 |
Budget Value (Tested, Decent Quality)
| Brand | Product | Form | EPA/DHA per 2 Softgels | Cost/Day (1g EPA+DHA) | Testing |
|---|---|---|---|---|---|
| Kirkland (Costco) | Fish Oil 1000mg | EE | 600mg (360/240) | ~$0.15 | ConsumerLab (passes) |
| Nature Made | Fish Oil 1200mg | EE | 720mg (432/288) | ~$0.20 | USP Verified |
| Now Foods | Ultra Omega-3 | EE | 750mg (500/250) | ~$0.25 | ConsumerLab |
Cost Per Gram EPA+DHA Calculator
Formula: (Price per bottle ÷ Servings per bottle) ÷ (EPA+DHA per serving in grams) = $/g EPA+DHA
| Product | Bottle Price | Servings | EPA+DHA/Serving | $/Serving | $/g EPA+DHA |
|---|---|---|---|---|---|
| Nordic Naturals ProOmega 2000 (60) | $54 | 60 | 1.125g | $0.90 | $0.80 |
| Carlson Very Finest (100) | $40 | 100 | 0.8g | $0.40 | $0.50 |
| Sports Research Triple (180) | $35 | 90 (2 caps) | 1.0g | $0.39 | $0.39 |
| Kirkland (400) | $15 | 200 (2 caps) | 0.6g | $0.075 | $0.125 |
Note: EE forms (Kirkland, Nature Made) need high-fat meal for absorption. rTG forms (Nordic, Sports Research) absorb well anytime.
Dosing Protocol by Population
| Population | EPA+DHA Target | Notes |
|---|---|---|
| Healthy Adult (Maintenance) | 500mg/day | 2 servings fatty fish/week = equivalent |
| Cardiovascular Risk / High Triglycerides | 2–4g/day (Rx: Vascepa® 4g) | Medical supervision; monitor bleeding |
| Pregnancy / Lactation | 300mg DHA + 200mg EPA | 3rd trimester critical; continue breastfeeding |
| Depression (Adjunct) | 1–2g EPA (high-EPA) | Adjunct to therapy/meds; EPA ≥ DHA |
| ADHD (Children) | 500mg EPA+DHA (>60% EPA) | Liquid easier; monitor response 12wks |
| Older Adult (>65) | 1g/day (balanced) | Cognitive + cardiovascular; check meds |
| Vegetarian / Vegan | 300–500mg DHA (algal) | Algal oil; EPA lower, consider separate EPA |
Frequently Asked Questions
Does fish oil go bad in the bottle?
Yes. Once opened: 90 days max (refrigerated). Unopened: check expiration + TOTOX on CoA. Signs of rancidity: fishy burps, rancid smell, cloudy oil. Freeze softgels to extend life.
Krill oil vs. fish oil — worth it?
For most: no. Krill = 40–80mg EPA/DHA per cap (vs. 500–1000mg fish oil). Cost/g EPA+DHA = 5–10x higher. Astaxanthin benefit = marketing (dose too low). Only advantage: no burps, phospholipid form. Buy high-quality rTG fish oil instead.
Can I get enough from food?
2 servings/week fatty fish (salmon, sardines, mackerel, herring, anchovies) = ~500mg EPA+DHA/day average. If you eat this consistently: supplement optional. If not: supplement recommended.
What about cod liver oil?
Contains vitamin A + D (variable). Risk of vitamin A toxicity at high omega-3 doses. Better: separate high-quality fish oil + targeted D3/A if needed.
References
- GOED. “Voluntary Monograph.” Global Organization for EPA and DHA Omega-3s. 2024.
- Innes JK, Calder PC. “Marine Omega-3 (n-3) Fatty Acids for Cardiovascular Health.” BMJ. 2020;368:m584.
- Sublette ME, et al. “Meta-Analysis: EPA for Depression.” J Clin Psychiatry. 2011;72(12):1577-1584.
- ConsumerLab. “Fish Oil & Omega-3 Supplements Review.” 2024.
- IFOS. “International Fish Oil Standards.” 2024.
- Harris WS, et al. “Omega-3 Index as a Risk Factor.” Prostaglandins Leukot Essent Fatty Acids. 2018;135:20-27.
