Graded against 178,763 supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, NIH DSLD
Fish Oil
Fatty AcidLast updated April 5, 2026
AVELOR SUMMARY
Fish oil delivers EPA and DHA, the two omega-3 fatty acids your body actually uses.
Backed by 138 RCTs, 20 meta-analyses, and 243,000+ participants, our research confirms fish oil reliably and significantly reduces triglycerides.
It also shows meaningful benefits for depression symptoms and inflammatory conditions.
However, it does NOT reduce cardiovascular events (heart attacks, strokes) in most populations, a critical distinction that many supplement companies ignore.
At high doses (>1g/day), there's a dose-dependent atrial fibrillation risk in people with cardiovascular disease.
EVIDENCE GRADES
Triglycerides47 studies, 15,492 participants, large improvement
Strong evidenceGrade A
Depression Symptoms
Strong evidenceGrade A
Inflammation (CRP)
Strong evidenceGrade A
Blood Pressure
Moderate evidenceGrade B
LDL Cholesterol
Moderate evidenceGrade B
HDL Cholesterol
Moderate evidenceGrade B
Cardiovascular EventsNo effect in most populations
No benefit foundGrade D
WHAT IT DOES
Dramatically reduces triglycerides, Grade A evidence. The most reliable and clinically significant benefit. Large effect size across 47 studies.
Reduces depression symptoms, Grade A evidence. EPA appears more effective than DHA for mood benefits. Works best as adjunct to treatment.
Reduces inflammatory markers, Grade A evidence for CRP reduction. Useful for inflammatory conditions like rheumatoid arthritis.
Modestly lowers blood pressure, Grade B evidence, especially above 2g/day EPA+DHA.
Does NOT prevent heart attacks/strokes, Despite decades of marketing, Grade D evidence for cardiovascular event prevention in most populations.
Mixed effect on LDL, May actually slightly increase LDL cholesterol in some people while improving other lipid markers.
OPTIMAL DOSAGE
General health minimum: 250mg combined EPA+DHA per day (can get from 2 servings of fatty fish per week)
For cardiovascular benefit (triglycerides): 2-4g combined EPA+DHA per day
For depression: 1-2g per day (EPA-dominant formulations preferred)
For inflammation: 2-4g per day
American Heart Association recommendation: 1g daily for cardiovascular benefit
Pregnancy: Increase DHA by at least 200mg/day
Breastfeeding: 1,000mg combined EPA+DHA per day
Best form: Triglyceride or phospholipid form (krill oil), more stable against oxidation than ethyl ester form
Timing: Take with meals containing fat. Reduces fishy burps.
With food: Yes, always take with food for better absorption and tolerability.
Dose-dependent (>1g/day): Atrial fibrillation, risk rises sharply above 1g/day in people with cardiovascular disease. Highest risk at 4g/day.
High-dose (4g/day): Increased bleeding risk (primarily with prescription EPA ethyl ester). Minimal to nonexistent at lower doses.
Possible: Mild liver function changes (slightly higher ALT), itching
Important context: At normal supplemental doses (1-2g/day), fish oil is very well tolerated for long periods.
Precautions
Pregnancy:Caution. Safe up to 3g/day combined EPA+DHA. Limited data on higher doses. Consider discontinuing during third trimester, limited observational evidence suggests increased bleeding risk after delivery.
Breastfeeding:Safe. 1,000mg/day recommended.
Cardiovascular disease:Dose-dependent atrial fibrillation risk. Sharp rise above 1g/day. European and UK agencies recommend permanent discontinuation of omega-3 ethyl esters if atrial fibrillation occurs.
Previous heart attacks: Increased stroke risk with fish oil supplementation.
Liver cirrhosis: Risk of decreased blood pressure and increased bleeding.
Colorectal cancer surgery: Possible increased perioperative/postsurgical complications.
Cardioverter defibrillator implant: Mixed evidence on proarrhythmic effects. Use with caution.
Seafood allergies: Little to no fish protein in purified fish oil, most allergic people tolerate it. However, case reports of anaphylaxis exist. Caution warranted.
Major depressive disorder: One case report of fish oil inducing hypomania.
Quality Concerns
This is a major issue for fish oil. Key concerns:
Some products contain less EPA/DHA than labeled. Others are within acceptable limits.
Soybean oil adulteration detected in the Brazilian market.
Higher-than-expected saturated fat in some products indicates poor purification.
Oxidation (rancidity) is common, studies from multiple countries find substantial proportions of supplements are significantly oxidized. Oxidized fish oil may be ineffective or even worsen lipid profiles.
Storage tips: Keep encapsulated, at room temperature, away from light and heat. Capsules > syrup for stability. Phospholipid forms (krill) > triglycerides > ethyl esters for oxidation resistance.
Mercury: Generally not a concern in purified fish oil (mercury binds to protein, not oil). Smaller fish (anchovy, sardine, mackerel) have lower pollutant levels.
WADA Status
Not Prohibited. Not on the 2026 WADA list.
WHO SHOULD BE CAREFUL
QUALITY CONCERNS
This is a major issue for fish oil. Key concerns:
Some products contain less EPA/DHA than labeled. Others are within acceptable limits.
Soybean oil adulteration detected in the Brazilian market.
Higher-than-expected saturated fat in some products indicates poor purification.
Oxidation (rancidity) is common, studies from multiple countries find substantial proportions of supplements are significantly oxidized. Oxidized fish oil may be ineffective or even worsen lipid profiles.
Storage tips: Keep encapsulated, at room temperature, away from light and heat. Capsules > syrup for stability. Phospholipid forms (krill) > triglycerides > ethyl esters for oxidation resistance.
Mercury: Generally not a concern in purified fish oil (mercury binds to protein, not oil). Smaller fish (anchovy, sardine, mackerel) have lower pollutant levels.
HOW AVELOR SCORES THIS
Present in proper dose (1-2g combined EPA+DHA, triglyceride form):✅ Green flag, well-studied, reliable for triglycerides and mood
Ethyl ester form:⚠️ Yellow flag, more prone to oxidation, slightly less bioavailable than triglyceride form
No EPA/DHA breakdown on label:⚠️ Yellow flag, total "fish oil" doesn't tell you how much EPA+DHA you're actually getting
In a proprietary blend:⚠️ Yellow flag, impossible to verify EPA+DHA content
Above 4g/day in people with heart disease:🔴 Red flag, significant atrial fibrillation risk
CLINICAL REFERENCES
Reference identifiers on this page are being re-verified against PubMed. Some may not yet link to the paper named beside them.
1.
**, Hu Y et al. "Marine Omega-3 Supplementation and Cardiovascular Disease: An Updated Meta-Analysis of 13 Randomized Controlled Trials." *J Am Heart Assoc*, 2019. Key finding: Marine omega-3 supplementation associated with lower risk of MI, CHD death, and total CHD.
Marine Omega-3 Supplementation and Cardiovascular Disease: An Updated Meta-Analysis of 13 Randomized Controlled Trials.. (2019). PMID: 31567003
2.
**, Skulas-Ray AC et al. "Omega-3 Fatty Acids for the Management of Hypertriglyceridemia." *Circulation*, 2019. Key finding: AHA Science Advisory, 4g/day of EPA+DHA reduces triglycerides by 20-30%.
Omega-3 Fatty Acids for the Management of Hypertriglyceridemia.. (2019). PMID: 29387889
Independently graded against 178,763 indexed supplements and 757 reviewed supplement and medication pairs, sourced from PubMed, FDA CAERS, openFDA, and NIH DSLD | Last updated: April 5, 2026
Not medical advice. Based on published clinical research and systematic reviews.
Medication review
This source review is incomplete. It does not establish which combinations are safe or appropriate for you.
Warfarin (Coumadin)
Source review required
The reviewed sources do not establish one bleeding or INR effect for every fish-oil product. A warfarin case report and a small controlled study had different findings.
Have the prescribing team review the exact omega-3 product and decide on bleeding or INR monitoring. Warfarin dose changes require the prescriber's instructions. The linked LOVAZA label covers monitoring with prescription EPA/DHA ethyl esters. Other mechanism and risk statements in this entry still need source review.
Evidence for prescription EPA/DHA ethyl esters does not establish the same effect for every fish-oil supplement.
FDA label, DailyMed set ID 21cfa4ce-0b05-47ed-b268-339eb1b83b75
(LOVAZA, section 7.1; monitoring/action only; legacy mechanism and risk pending source review)
Official source snapshot reviewed; this does not establish all claims in this entry.
Clopidogrel (Plavix)
Source review required
The cited observational study included aspirin as well as clopidogrel and did not find a statistically significant bleeding difference. It does not establish the risk of every fish-oil and clopidogrel combination.
Review the exact omega-3 product with the prescribing team. The LOVAZA label calls for periodic monitoring when prescription EPA/DHA ethyl esters are used with antiplatelet medicines; it does not establish a monitoring plan for every fish-oil supplement.
The cited prescription products have different formulations. Their precautions do not establish a monitoring plan for every fish-oil supplement.
Official source snapshot reviewed; this does not establish all claims in this entry.
High-dose Aspirin
Source review required
The reviewed trials do not establish a high-dose aspirin interaction estimate or a fish-oil dose cutoff for this entry. ASCEND studied 100 mg aspirin and 1-g omega-3 capsules; those exposures do not validate this high-dose aspirin claim.
The prescribing team needs the aspirin dose and exact omega-3 formulation before giving monitoring or procedure instructions. This entry supplies no universal 3-g cutoff or stop-before-surgery instruction.
The available studies do not define a high-dose aspirin threshold for this interaction. Findings for low-dose aspirin or one prescription omega-3 product cannot establish the effect of other doses or formulations.
Archived abstract; full report access separately enumerated.
Blood pressure medications
Source review required
Blood-pressure effects vary by omega-3 preparation. The reviewed evidence does not establish a predictable benefit or hypotension risk for every blood-pressure medicine.
Have the prescribing team review the exact omega-3 product and blood-pressure medicine, including whether monitoring is needed.
General blood-pressure findings do not establish the effect of combining a particular omega-3 product with a named medicine.
Archived abstract; full report access separately enumerated.
Orlistat (Alli)
Source review required
Orlistat reduces fat absorption. The reviewed omega-3 study measured formulation-specific absorption, not clinical effectiveness or a validated two-hour schedule.
Review the exact omega-3 formulation and timing with the pharmacist or prescribing team. The two-hour XENICAL label instruction concerns fat-soluble vitamin supplements, not a validated fish-oil schedule.
The vitamin-spacing instruction in the XENICAL label is not a fish-oil timing rule. The exact product and formulation matter.
Archived abstract; full report access separately enumerated.
Other combinations awaiting review (9)
Fish Oil with Anticoagulants
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 fish oil high-dose with Warfarin
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 fish oil high-dose with Clopidogrel
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Fish Oil with Aspirin
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 fish oil high-dose with Aspirin
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 (EPA/DHA) with Lisinopril
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 (EPA/DHA) with Losartan
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 (EPA/DHA) with Ramipril
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.
Omega-3 (EPA/DHA) with Valsartan
Source review required
The risk, benefit, preparation and dose context for this recorded combination remain under review. This entry does not establish that the combination is safe.