Fatty Acid

Krill Oil

Euphausia superba oil

Evidence TierBWADA NOT PROHIBITED

tuneTypical Dose

1,000–3,000 mg

watchEffect Window

4–12 weeks for lipid panel and inflammatory marker shifts.

check_circleCompliance

WADA NOT PROHIBITED

Overview

Clinical Summary

Krill oil provides omega-3 fatty acids partly bound to phospholipids and contains astaxanthin. It is used to raise omega-3 status for triglyceride and inflammation-related goals, often with good tolerance.

Trials show krill oil increases omega-3 blood levels and can modestly lower triglycerides. Some studies report improvements in joint discomfort and inflammatory biomarkers, though results vary. Minority evidence suggests benefits for menstrual symptoms and cognitive measures. Practical effect depends on achieving adequate EPA plus DHA intake, since many products provide lower absolute doses than fish oil.

Delivers EPA and DHA bound to phospholipids (phosphatidylcholine), increasing water solubility and gut absorption vs triglyceride-form fish oil. Contains natural astaxanthin with antioxidant and anti-inflammatory properties.

Outcomes

What This Is Expected To Influence

Primary Outcomes

  • Reliably increases Omega-3 Index via phospholipid-bound EPA/DHA with superior bioavailability per mg vs fish oil
  • Reduces triglycerides and systemic inflammation markers (CRP)

Secondary Outcomes

  • Improves PMS and dysmenorrhea symptoms
  • Provides natural astaxanthin (antioxidant)

Safety

Contraindications and Interactions

Contraindications

  • Shellfish/crustacean allergy (absolute)
  • Anticoagulant therapy (additive bleeding risk)

Side effects

  • Fishy burps
  • GI upset (less than fish oil)

Interactions

  • Anticoagulants, warfarin, aspirin (potentiates bleeding risk)
  • Blood glucose medications (may affect levels)

Avoid if

  • Shellfish/crustacean allergy
  • Upcoming surgery (stop 1–2 weeks prior)

Evidence

Study-level References

krill-oil-SRC-001RCT
Sourceopen_in_new

Ramprasath VR, et al. "Enhanced increase of omega-3 index in healthy individuals with response to 4-week n-3 fatty acid supplementation from krill oil versus fish oil." Lipids Health Dis. 2013.

Population: Healthy Adults

Dose protocol: Source-listed

Key findings: Krill oil supplementation resulted in a significantly greater increase in the Omega-3 index compared to fish oil when matched for total EPA+DHA dose, indicating higher bioavailability.

Paper content

Krill oil supplementation resulted in a significantly greater increase in the Omega-3 index compared to fish oil when matched for total EPA+DHA dose, indicating higher bioavailability.

krill-oil-SRC-002Systematic review and meta-analysis of randomized controlled trials.
Sourceopen_in_new

Meng J, Wang X, Li Y, et al. Krill oil for knee osteoarthritis: A meta-analysis of randomized controlled trials. Medicine (Baltimore). 2025;104(7):e41566. doi:10.1097/MD.0000000000041566. PMID:39960912.

Population: Adults with knee osteoarthritis across 5 RCTs.

Dose protocol: Krill oil versus usual care or placebo across 5 RCTs

Key findings: Significant improvements in WOMAC pain, stiffness, and function. VAS pain nonsignificant. No difference in adverse events.

Notes: Meta-analysis of 730 participants. Modest trial count limits precision.

Paper content

This meta-analysis pooled 5 RCTs (730 participants) evaluating krill oil for knee osteoarthritis. Krill oil showed significant benefits for WOMAC pain, stiffness, and functional outcomes compared to controls. VAS pain scores did not reach significance. Blood markers and adverse event rates did not differ between groups. The results support krill oil as a modestly effective option for OA joint symptoms, though the number of included trials is small and effect sizes are not large.

krill-oil-SRC-003Randomized, double-blind, controlled trial (secondary analysis).
Sourceopen_in_new

Hayman O, Alkhedhairi SA, Combet E, et al. Do the effects of krill oil supplementation on skeletal muscle function and size in older adults differ by sex, age or BMI. J Nutr Health Aging. 2026;29(3):100747. doi:10.1016/j.jnha.2025.100747. PMID:41344001.

Population: Healthy adults aged 65 years and older with BMI under 35, exercising less than 1 hour per week.

Dose protocol: 4 g/day krill oil versus control oil for 6 months

Key findings: Improvements in muscle strength, size, and physical function comparable across age, sex, and BMI subgroups. Sex-specific differences in membrane excitability.

Notes: Secondary subgroup analysis. Supports broad applicability of muscle benefits in older adults.

Paper content

This secondary analysis of a randomized double-blind trial examined whether krill oil effects on muscle function and size in older adults differed by sex, age, or BMI. 94 sedentary adults aged 65+ received 4 g/day krill oil or control oil for 6 months. Improvements in muscle strength, size, and physical function were comparable across all subgroups, with no significant interaction effects. Sex-specific differences appeared only in membrane excitability measures. The study supports that krill oil benefits for muscle health in older adults are not limited to specific demographic subgroups.

krill-oil-SRC-004Randomized controlled trial.
Sourceopen_in_new

Alblaji M, Gray SR, Almesbehi T, Morrison DJ, Malkova D. Benefits of Krill Oil Supplementation During Alternate-Day Fasting in Adults With Overweight and Obesity: A Randomized Trial. Obesity (Silver Spring). 2025. doi:10.1002/oby.24354. PMID:40671417.

Population: Adults with overweight and obesity (mean BMI 31.1 kg/m2, mean age 39 years).

Dose protocol: 191 mg EPA + 94 mg DHA/day from krill oil during 8 weeks of alternate-day fasting

Key findings: Krill oil group maintained fat-free mass and handgrip strength while placebo group declined during caloric restriction.

Notes: Small sample (n=41). Specific to fasting-induced weight loss context.

Paper content

This RCT tested krill oil supplementation (191 mg EPA, 94 mg DHA/day) versus placebo during 8 weeks of alternate-day fasting in 41 adults with overweight and obesity. The krill oil group maintained fat-free mass and handgrip strength, while the placebo group experienced significant declines in both measures during weight loss. The study suggests that krill oil may help preserve lean mass and muscle function during caloric restriction, though the sample size is small and the fasting protocol is specific.

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