Omega-3 Index / Fatty Acids
The Omega-3 Index measures EPA plus DHA as a percentage of total fatty acids in red blood cell membranes. It reflects long-term omega-3 intake and is inversely associated with cardiovascular death, with targets above 8 percent linked to lowest risk. Values under 4 percent are common in Western diets and can usually be raised with oily fish or fish oil supplementation.
Units: % of red-cell fatty acids. Check the units on your report before comparing to any range here.
Optimal range: who says what
Institutions, researchers and practitioners draw the line in different places. Each position is listed with who holds it and, where a document states it, a link. How we verify ranges.
- Institution or study≥8%Harris & von Schacky 2004 (Prev Med)An index of 4% or below was associated with the least cardioprotection. Harris co-invented the Omega-3 Index test, which OmegaQuant sells
- Institution or study>6.8% (top quintile)Framingham Heart Study (Harris et al. 2018)Compared with the lowest quintile (below 4.2%), the top quintile had 34% lower all-cause mortality and 39% lower incident cardiovascular disease
- Named practitioner>8%Dr. Rhonda Patrick · How Vitamin D, Omega-3s & Exercise May Increase Longevity
- Named practitioner>8%OmegaQuant · What is the Omega-3 Index?Disclosure: OmegaQuant developed and sells the Omega-3 Index test its target refers to.
- Lab reference intervalTarget: >8%, Intermediate: 4-8%, Undesirable: <4%What a lab report flags against. A lab interval is not an optimal target.
Practitioner targets are individual positions, often tighter than guideline ranges. Each was checked against its article before publishing.
8 of 21 itemized panels
Advanced / Specialty Markers
What is Omega-3 Index / Fatty Acids?
The Omega-3 Index measures the percentage of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) in red blood cell membranes. It reflects your long-term omega-3 fatty acid status over the past 3-4 months, similar to how HbA1c reflects glucose control. This biomarker was developed by Dr. William Harris and is considered the gold standard for assessing omega-3 status.
EPA and DHA are essential omega-3 fatty acids that must be obtained from diet or supplements—your body cannot produce them efficiently from plant-based ALA (alpha-linolenic acid). They are structural components of every cell membrane in your body, particularly concentrated in the brain (60% of brain tissue is fat, much of it DHA) and heart. An Omega-3 Index below 8% is associated with increased risk of sudden cardiac death, cognitive decline, and systemic inflammation.
The target Omega-3 Index for longevity optimization is >8%, though most Americans have levels between 4-5%. Achieving this typically requires consuming 2-3 grams of EPA+DHA daily from fatty fish (salmon, sardines, mackerel) or high-quality fish oil supplements. The ratio of omega-6 to omega-3 fatty acids also matters—the modern Western diet has a ratio of 15-20:1 when optimal is closer to 4:1 or lower.
Why the Omega-3 Index Matters for Longevity
- Cardiovascular protection: An Omega-3 Index >8% is associated with a 30% reduction in risk of sudden cardiac death and significantly lower triglycerides. EPA and DHA reduce inflammation, stabilize heart rhythm, and improve endothelial function.
- Brain health and cognition: DHA is the primary structural fat in the brain. Higher Omega-3 Index is associated with larger brain volume, better cognitive function, and reduced risk of Alzheimer's disease. Low levels accelerate brain aging by 1-2 years.
- Anti-inflammatory effects: EPA and DHA are precursors to resolvins and protectins—powerful anti-inflammatory molecules that resolve chronic inflammation without suppressing immune function. This is critical for longevity since chronic inflammation drives most age-related diseases.
- Mental health: Higher Omega-3 Index is associated with lower rates of depression, anxiety, and improved mood stability. EPA in particular has potent antidepressant effects comparable to some medications at doses of 1-2 grams daily.
- Eye health: DHA is highly concentrated in the retina. Adequate levels protect against age-related macular degeneration (AMD), the leading cause of blindness in older adults.
- Cellular aging: Higher Omega-3 Index is associated with longer telomeres (protective caps on chromosomes that shorten with age). Each 1% increase in Omega-3 Index may slow cellular aging by several months.
Interpretation bands (curated, PMID-backed)
Holder: OptimizeBiomarkers editorial synthesis of: Effect of omega-3 fatty acids on cardiovascular outcomes: A systematic review and meta-analysis (Khan et al., 2021); Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials (Bernasconi et al., 2021); Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease (Abdelhamid et al., 2018). No single paper sets these cutoffs; for attributed targets see who says what.
Optimal (Longevity)>8%▼
- Exceptional omega-3 status associated with maximal cardiovascular and brain protection
- This level significantly reduces risk of sudden cardiac death, cognitive decline, and systemic inflammation
- Requires consistent intake of 2-3g EPA+DHA daily
Good (Standard)6-8%▼
- Adequate omega-3 status with good cardiovascular and cognitive protection
- Most benefits are achieved in this range, though higher is better for longevity optimization
Acceptable (Functional)4-6%▼
- Below optimal omega-3 status
- This is where most Americans fall
- Increased risk of cardiovascular events, cognitive decline, and inflammatory conditions
- Supplementation strongly recommended
Suboptimal (Standard)<4%▼
- Severely deficient omega-3 status associated with significantly increased risk of sudden cardiac death, depression, cognitive impairment, and accelerated aging
- Immediate intervention required
- Effect of omega-3 fatty acids on cardiovascular outcomes: A systematic review and meta-analysis.
- Effect of Omega-3 Dosage on Cardiovascular Outcomes: An Updated Meta-Analysis and Meta-Regression of Interventional Trials.
- Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.
What raises or lowers Omega-3 Index / Fatty Acids
Causes of low Omega-3 Index / Fatty Acids
- Low dietary intake of fatty fish (<1 serving per week)
- No supplementation with fish oil or algae-based omega-3s
- High intake of omega-6 fatty acids from processed foods and vegetable oils (competes with omega-3 absorption)
- Genetic variations affecting omega-3 metabolism (some people convert dietary omega-3s less efficiently)
- Chronic inflammatory conditions or malabsorption disorders (Crohn's, celiac, IBD) that impair fat absorption
- Medications that impair fat absorption (Orlistat, bile acid sequestrants)
Symptoms when Omega-3 Index / Fatty Acids is high or low
When high
Omega-3 Index cannot be "too high" in a pathological sense. Very high intake (>5g EPA+DHA daily) may cause: mild fishy aftertaste or burping, slightly increased bleeding time (though not clinically significant in most people), mild gastrointestinal upset. These are generally mild and dose-dependent, not dangerous.
High: Not applicable
When low
Most people with low Omega-3 Index are asymptomatic initially. However, chronic deficiency may manifest as: dry/rough skin, brittle hair and nails, difficulty concentrating or brain fog, mood issues (depression, anxiety, irritability), joint pain or stiffness, poor wound healing, frequent infections. Note: These symptoms are non-specific and can have many causes.
Very low: Rare as isolated deficiency
How to move Omega-3 Index / Fatty Acids
Effect sizes (how much something moves the marker) appear only where the paper cited under the item states them. Talk to your clinician before starting or changing any medication or supplement.
Fatty Fish Diet
Eat salmon (wild-caught preferred), sardines, mackerel, herring, or anchovies 3-4 times weekly. A 6oz serving of salmon provides ~2-3g EPA+DHA. This is the most bioavailable and well-tolerated source of omega-3s, and includes other nutrients like vitamin D, selenium, and astaxanthin.
Fish Oil Supplementation
Take 2-3g combined EPA+DHA daily from molecular distilled, third-party tested fish oil. Look for products with IFOS (International Fish Oil Standards) certification. Triglyceride or phospholipid forms are better absorbed than ethyl ester forms. Take with meals containing fat for optimal absorption. Consider algae-based omega-3s if vegetarian.
Balance Omega-6/Omega-3 Ratio
Minimize processed vegetable oils (soybean, corn, safflower, sunflower) which are high in omega-6 fatty acids that compete with omega-3s and promote inflammation. Cook with olive oil, avocado oil, or coconut oil instead. Western diets are far higher in omega-6 than omega-3.
Monitor and Adjust
The Omega-3 Index responds slowly to dietary changes—it takes 3-4 months to reach steady state after starting supplementation. Retest every 3-6 months to confirm you stay above 8%, the target Harris and von Schacky proposed. Individual absorption varies significantly; some people need 3-4g EPA+DHA daily to reach target levels.
Prescription Options
For those with very high triglycerides (>500 mg/dL) or difficulty absorbing supplements, prescription omega-3 products like Vascepa (icosapent ethyl, 4g EPA daily) or Lovaza (EPA+DHA ethyl esters) may be appropriate. These are FDA-approved for cardiovascular risk reduction and covered by insurance.
Scientific Evidence
The Omega-3 Index as a Risk Factor
Harris and von Schacky proposed the red blood cell EPA+DHA percentage, the Omega-3 Index, as a risk factor for death from coronary heart disease. In the published studies they analyzed, an index of 8% or higher was associated with the greatest protection and 4% or lower with the least.
Source: The Omega-3 Index: a new risk factor for death from coronary heart disease?
Omega-3 Index Cut-Points Across 10 Cohorts
Using data from 10 cohort studies (mean index 6.1%), each 1 SD higher Omega-3 Index was associated with 15% lower risk of fatal coronary heart disease. The authors estimated that moving from 4% to 8% would lower that risk by about 30%, supporting <4% and >8% as targets.
Supplement Dose and Cardiovascular Outcomes
A meta-analysis of 40 trials (135,267 participants) found EPA+DHA supplementation reduced heart attacks (relative risk 0.87) and coronary events (0.90), with benefit rising with dose. The broad composite of all cardiovascular events was not significantly reduced (0.95).
Cochrane Review: Little Effect on Mortality
A Cochrane review of 79 trials (112,059 participants) found increasing long-chain omega-3 intake had little or no effect on all-cause mortality (relative risk 0.98), cardiovascular events (0.99), or stroke. A small reduction in coronary events did not hold up in sensitivity analyses.
Source: Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.
EPA Alone Versus EPA+DHA
A meta-analysis of 38 trials (149,051 participants) found omega-3 fatty acids reduced cardiovascular mortality (relative risk 0.93) and non-fatal heart attack (0.87), with larger effects for EPA alone than for EPA+DHA. Omega-3 use increased atrial fibrillation (relative risk 1.26).
Source: Effect of omega-3 fatty acids on cardiovascular outcomes: A systematic review and meta-analysis.
Which Providers Test Omega-3 Index / Fatty Acids?
Cheapest: Superpower at $349/year. Most comprehensive: Function Health, 160+ biomarkers for $365/year.
8 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
 Superpower | $349 | 100+ | $3.49 |
 WHOOP Advanced Labs | $349 | 65 | $5.37 |
 Function Health | $365 | 160+ | $2.28 |
| $365 | 100+ | $3.65 | |
| $499 | 100+ | $4.99 | |
| $700 | 138 | $5.07 | |
| $895 | 100+ | $8.95 | |
| $1950 | 130+ | $15.00 |
$/Biomarker is annual cost divided by the panel's advertised biomarker count, not the price of this one test. We track 23 blood test providers (32 plans); 21 of those plans are itemized marker by marker. Compare all of them.
13 itemized panels do not include Omega-3 Index / Fatty Acids
Labcorp OnDemand · Life Extension Elite · Everlywell · Mito Health · InsideTracker · Marek Health Base · Marek Health Comprehensive · Empirical Health · Oura Health Panels · SiPhox Health · Hims Labs · Healthspan · Vitality Blueprint Standard
11 providers not itemized in our matrix
We have not itemized these marker by marker (some sell tests one at a time), so this page cannot say whether they offer Omega-3 Index / Fatty Acids. Check with them directly.
Life Extension Standard · Quest Health · Ultrahuman Blood Vision · Lifeforce · Hundred Health · Personalabs · Walk-In Lab · HealthLabs · WHOOP Specialized Panels · Marek Health Essential · Vitality Blueprint Upload
Experts discussing Omega-3 Index / Fatty Acids
Podcast episodes where clinicians and researchers cover this marker in depth. Curated by hand; an episode is listed only when the marker is a substantial topic, not a passing mention.
- Dr. Rhonda Patrick: Micronutrients for Health & LongevityDisclosure: Huberman Lab has been sponsored by Function Health, which appears in our blood-test comparisons.
- Check These Biomarkers on Your Next Blood Test
- How Vitamin D, Omega-3s, & Exercise May Increase Longevity
- The Powerful Longevity Benefits of Omega-3
- Does omega-3 reduce cardiovascular disease? Comparing major trials
- Essential Fatty Acids, Fish & Fish Oil
Frequently Asked Questions
What is the optimal range for Omega-3 Index / Fatty Acids?
Published positions differ: ≥8% (Harris & von Schacky 2004 (Prev Med)); >6.8% (top quintile) (Framingham Heart Study (Harris et al. 2018)). Named practitioners target: >8% (Dr. Rhonda Patrick); >8% (OmegaQuant). Lab reference interval: Target: >8%, Intermediate: 4-8%, Undesirable: <4%. That is what a lab report flags against, not an optimal target.
Which blood test providers include Omega-3 Index / Fatty Acids?
8 of the 21 blood testing panels we itemize marker by marker include Omega-3 Index / Fatty Acids in their panels. This biomarker is widely available across major providers.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed Sep 23, 2026 · First published Sep 30, 2025