What omega-3 actually does in the body
Omega-3s (EPA and DHA) are structural fats that lower triglycerides, support the brain and eyes, and modulate inflammation. What they do, and the dose that does it.
What people ask us next.
- What does omega-3 do in the body?
- EPA and DHA serve structural and signaling roles. DHA is a major structural fat in the brain and retina; both are precursors to molecules that resolve inflammation. The best-proven clinical effect is lowering blood triglycerides by ~15-30% at pharmacologic doses (Skulas-Ray 2019). Cardiovascular-event benefit is real for high-dose EPA in high-risk patients but mixed in the general population.
- What is omega-3 good for?
- Most reliably, lowering triglycerides at higher doses. It has a documented structural role in brain and eye development (hence the pregnancy emphasis), a modest anti-inflammatory effect in conditions like rheumatoid arthritis, and a cardiovascular-event benefit specifically with high-dose prescription EPA in high-risk patients (Bhatt 2019). It is not a proven broad disease preventive for low-risk people.
- Is fish oil the same as omega-3?
- Fish oil is a source of omega-3, not a synonym. Fish oil contains the long-chain omega-3s EPA and DHA, which are the active forms. Plant sources provide ALA, a shorter omega-3 that the body converts to EPA and DHA only at ~5-10% efficiency (NIH ODS). So fish oil delivers omega-3 directly, while flax or chia delivers a precursor.
- How much omega-3 per day should I take?
- For general health, 250-500 mg of combined EPA+DHA per day, achievable with about two servings of oily fish weekly or a supplement. Lowering triglycerides therapeutically takes 2-4 g/day under medical guidance. When buying, read the EPA+DHA number, not the total fish-oil weight; our fish oil ranking compares products by $/mg of EPA+DHA.
- Can I get enough omega-3 from plants?
- Partly, but unreliably for EPA and DHA. Flax, chia, and walnuts supply ALA, which converts to the active EPA and DHA at only ~5-10% (NIH ODS). Vegetarians and vegans who want guaranteed EPA and DHA should use an algae-based omega-3 supplement, which provides the long-chain forms directly without fish.
- Is more omega-3 always better?
- No. The triglyceride benefit is dose-dependent up to a few grams, but very high doses can prolong bleeding time and, in some trials, modestly raised atrial fibrillation risk. General-health intake (250-500 mg/day) carries no such concern. High therapeutic doses (2-4 g/day) belong under clinician oversight, not as open-ended self-dosing.
Every claim, cited.
- [01]NIH Office of Dietary Supplements. Omega-3 Fatty Acids Fact Sheet for Health Professionals. EPA/DHA/ALA, conversion efficiency, intake recommendations.
- [02]Skulas-Ray AC, Wilson PWF, Harris WS, et al. 2019. Omega-3 fatty acids for the management of hypertriglyceridemia: a science advisory from the American Heart Association. Circulation 140(12):e673-e691. ~15-30% triglyceride reduction at 2-4 g/day.
- [03]Bhatt DL, Steg PG, Miller M, et al. 2019. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia (REDUCE-IT). N Engl J Med 380(1):11-22. High-dose EPA reduced events in high-risk statin-treated patients.
- [04]Dyerberg J, Madsen P, Moller JM, et al. 2010. Bioavailability of marine n-3 fatty acid formulations. Prostaglandins Leukot Essent Fatty Acids 83(3):137-141. Triglyceride form more bioavailable than ethyl ester.
The Larderlab Team builds evidence-led frameworks for eating, lifting, and stocking a kitchen. We cite every claim. We publish the spreadsheet when possible. We buy what we review at retail price. When new data lands, we revise with a dated note.
Next in this hub.
What to Avoid When Taking Collagen: Five Caveats With Evidence Behind Them
Do not count it toward your protein target, do not judge it before 8 to 12 weeks, and if you form kidney stones, know that 30 g of gelatin raised urinary oxalate by 43 percent in a controlled study. The real caveats, and the myths.
8 min · rev 2026-08-24Foods High in Collagen: Why the Real List Is Shorter Than You Think
Collagen exists only in animal connective tissue, so no plant food contains any. Gelatin powder leads at 85.6 g of protein per 100 g, pork skin at 61.3 g. And the most-marketed source, bone broth, tested poorly against supplements.
8 min · rev 2026-08-24Ashwagandha Benefits: What the Trials Show, and the Liver Signal
Pooled across 12 trials in 1,002 people, stress fell with a standardised mean difference of 1.75 and anxiety by 1.55, but heterogeneity was above 83 percent and the certainty of evidence was rated low. The dose that was tested, and the hepatic case series.
8 min · rev 2026-08-24Get the Larderlab Macro Planner.
A Google Sheet that calculates your protein target, splits it across 3-5 meals, and ranks 20 protein sources by $/gram. Free. Copy-and-modify your own version.
By subscribing, you agree to our Privacy Policy. Unsubscribe anytime.