Fish oil triglycerides vs phospholipid-bound EPA/DHA — bioavailability trade-off
What this is
Head-to-head evidence table: Fish Oil (Omega-3 Triglycerides) vs Krill Oil (Phospholipid EPA/DHA) (form).
Why it matters
Fish oil and krill oil both deliver EPA and DHA — the two omega-3 fatty acids with robust cardiovascular, cognitive, and anti-inflammatory evidence. The key difference is molecular form: fish oil carries EPA/DHA in triglyceride (TG) form; krill oil carries EPA/DHA bound to phospholipids (PL). Phospholipid-bound omega-3s show superior absorption in some studies and come bundled with choline and astaxanthin. However, krill oil provides dramatically less EPA/DHA per capsule and costs 3–5× more per gram of EPA+DHA. For longevity purposes, total EPA+DHA dose is what the RCT literature supports.
What to do next
Load the winning stack preset in Architect and simulate interactions before purchasing.
Fish oil and krill oil both deliver EPA and DHA — the two omega-3 fatty acids with robust cardiovascular, cognitive, and anti-inflammatory evidence. The key difference is molecular form: fish oil carries EPA/DHA in triglyceride (TG) form; krill oil carries EPA/DHA bound to phospholipids (PL). Phospholipid-bound omega-3s show superior absorption in some studies and come bundled with choline and astaxanthin. However, krill oil provides dramatically less EPA/DHA per capsule and costs 3–5× more per gram of EPA+DHA. For longevity purposes, total EPA+DHA dose is what the RCT literature supports.
EPA+DHA per standard capsule
For cardiovascular longevity endpoints, you need 2–4 g/day of EPA+DHA; krill oil makes this very expensive
Fish Oil (Omega-3 Triglycerides)
High: quality concentrates deliver 500–900 mg EPA+DHA per 1 g capsule
Krill Oil (Phospholipid EPA/DHA)
Low: typical krill oil capsule delivers 100–250 mg EPA+DHA per 500 mg capsule
Bioavailability (EPA+DHA absorption)
Bioavailability advantage is real but smaller than krill oil marketing suggests; dose matters more at equal EPA+DHA
Fish Oil (Omega-3 Triglycerides)
Good with food; re-esterified triglyceride (rTG) form is superior to ethyl ester form
Krill Oil (Phospholipid EPA/DHA)
Phospholipid form may show 10–30% higher absorption in short-term studies (Maki 2009)
Cardiovascular RCT evidence
The massive REDUCE-IT and STRENGTH trials used fish oil derivatives, not krill oil
Fish Oil (Omega-3 Triglycerides)
REDUCE-IT (PMID 30345336): 4 g EPA (Vascepa) reduced major cardiac events 25% — the definitive omega-3 cardiovascular trial
Krill Oil (Phospholipid EPA/DHA)
No head-to-head cardiovascular outcome trials at effective EPA+DHA doses
Cognitive / anti-inflammatory evidence
Fish Oil (Omega-3 Triglycerides)
Extensive: DHA depletion in Alzheimer's brain; EPA for depression; MFOS and VITAL trials for inflammation
Krill Oil (Phospholipid EPA/DHA)
Emerging; limited dedicated cognitive RCTs; extrapolated from fish oil data + choline co-delivery
Bonus compounds (astaxanthin, choline)
Choline co-delivery is a genuine benefit for those not eating eggs regularly; astaxanthin dose is below therapeutic range
Fish Oil (Omega-3 Triglycerides)
None — pure EPA+DHA delivery
Krill Oil (Phospholipid EPA/DHA)
Contains astaxanthin (2 mg; mild antioxidant) and choline (~50 mg; cognitive support)
Oxidation stability
Rancid fish oil negates health benefits; COA testing is non-negotiable for quality fish oil
Fish Oil (Omega-3 Triglycerides)
Vulnerable — buy from brands with oxidation COA testing (TOTOX <26); store refrigerated
Krill Oil (Phospholipid EPA/DHA)
More stable — astaxanthin acts as natural antioxidant; fewer oxidation concerns
Cost per gram EPA+DHA
Fish Oil (Omega-3 Triglycerides)
$0.05–0.15/g EPA+DHA from quality rTG concentrates (e.g., Nordic Naturals, Carlson)
Krill Oil (Phospholipid EPA/DHA)
$0.80–2.00/g EPA+DHA from krill oil — 5–15× more expensive per unit of active omega-3
TNiC verdict
Fish oil wins on cost-effectiveness and total EPA+DHA dose per dollar. Krill oil is not meaningfully superior for longevity-relevant outcomes when EPA+DHA doses are equalized. Choose high-quality fish oil (triglyceride form, ≥70% omega-3 concentrate) over krill oil for most longevity protocols — the dose advantage matters more than the form advantage.
Choose Fish Oil (Omega-3 Triglycerides) when
Choose Krill Oil (Phospholipid EPA/DHA) when