Supplement
Omega-3 fatty acids, such as EPA and DHA, are fats that build cell membranes, including in the brain, and help steer inflammation. People most often look at them for major depression, where the evidence is limited: anxiety symptoms eased in people with depression, and pooled studies found depression symptoms improved. Those trials were small, including one analysis of just 50 people, so these are early findings.
Sources: PMID 30317101; PMID 37028202; PMID 40049535
- Updated
- How we grade
- 21 studies cited
- Best evidence
- Grade B
- Conditions studied
- 20
- Outcomes
- 60
- Graded outcomes
- 0338
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| High-density lipoprotein (HDL) Small Improvement | Improves (the measure goes up) | Small effect | 741 people | |||
| Total cholesterol | Improves (the measure goes down) | 1 study | 741 people | |||
Studies that measured total cholesterol | ||||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 435 people | ||||
| Triglycerides | Improves (the measure goes down) | 848 people | ||||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| C-Reactive Protein (CRP) Small Decrease | Improves (the measure goes down) | Small effect | 1,523 people | |||
| Interleukin 6 | Improves (the measure goes down) | 1 study | 1,523 people | |||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 1 study | 1,523 people | |||
Studies that measured total antioxidant capacity (tac) | ||||||
| Oxidative Stress Biomarkers | Improves (the measure goes down) | 1,523 people | ||||
| Superoxide Dismutase Activity | Improves (the measure goes up) | 1,523 people | ||||
| TNF-Alpha | Improves (the measure goes down) | 1,523 people | ||||
Cardiovascular Disease
- C-Reactive Protein (CRP): improves
- Interleukin 6: improves
- TNF-Alpha: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| C-Reactive Protein (CRP) Small Decrease | Improves (the measure goes down) | Small effect | 853 people | |||
| Interleukin 6 | Improves (the measure goes down) | 1 study | 853 people | |||
| TNF-Alpha | Improves (the measure goes down) | 853 people | ||||
| Vascular Function | Improves (the measure goes up) | 853 people | ||||
Depression
- Depression Symptoms: improves
- Anxiety Symptoms: improves
- Quality of Life: improves
Major Depressive Disorder (MDD)
- Anxiety Symptoms: improves
- Depression Symptoms: improves
- Sleep Quality: improves
Pregnancy and Delivery Health
- Blood glucose
- Infant Death Risk: improves
- Interleukin 6: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood glucose No effect | NoneNo effect | 1 study | 1 person | |||
| Infant Death Risk | Improves (the measure goes down) | 1 study | 16,066 people | |||
Studies that measured infant death risk | ||||||
| Interleukin 6 | Improves (the measure goes down) | 1 study | 1 person | |||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 1 study | 1 person | |||
Studies that measured total antioxidant capacity (tac) | ||||||
| Total cholesterol | Improves (the measure goes down) | 1 study | 1 person | |||
Studies that measured total cholesterol | ||||||
| C-Reactive Protein (CRP) | Improves (the measure goes down) | 1 person | ||||
| High-density lipoprotein (HDL) | Improves (the measure goes up) | 1 person | ||||
| Insulin | Changes; see studies | 1 person | ||||
| Low-density lipoprotein (LDL) | Improves (the measure goes down) | 1 person | ||||
| Oxidative Stress Biomarkers | Improves (the measure goes down) | 1 person | ||||
| Pregnancy Complications | Improves (the measure goes up) | 17,156 people | ||||
| Triglycerides | Improves (the measure goes down) | 1 person | ||||
Heart Failure
- Cardiovascular Disease Mortality
- Risk of Hospitalization for Heart Failure: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cardiovascular Disease Mortality No effect | NoneNo effect | 1 study | 45,585 people | |||
Studies that measured cardiovascular disease mortality | ||||||
| Risk of Hospitalization for Heart Failure | Improves (the measure goes down) | 45,585 people | ||||
Premature Birth
- Infant Death Risk
- Pregnancy Complications: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Infant Death Risk No effect | NoneNo effect | 1 study | 16,066 people | |||
Studies that measured infant death risk | ||||||
| Pregnancy Complications | Improves (the measure goes up) | 17,156 people | ||||
Chronic Obstructive Pulmonary Disease (COPD)
- 6-Minute Walking Test Performance
- Interleukin 6: improves
- Quality of Life: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| 6-Minute Walking Test Performance No effect | NoneNo effect | 203 people | ||||
| Interleukin 6 | Improves (the measure goes down) | 1 study | 218 people | |||
| Quality of Life | Improves (the measure goes up) | 1 study | 139 people | |||
Studies that measured quality of life | ||||||
| C-Reactive Protein (CRP) | Improves (the measure goes down) | 208 people | ||||
Infertility
- Seminal Motility
- Sperm Count: improves
- Sperm Quality: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Seminal Motility No effect | NoneNo effect | |||||
| Sperm Count | Improves (the measure goes up) | |||||
| Sperm Quality | Improves (the measure goes up) |
Obesity
- Body Fat
- Muscle Mass: improves
- Body Mass Index (BMI): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Body Fat No effect | NoneNo effect | 637 people | ||||
| Muscle Mass | Improves (the measure goes up) | 1 study | 637 people | |||
| Body Mass Index (BMI) | Improves (the measure goes down) | 637 people | ||||
| Weight | Improves (the measure goes down) | 637 people | ||||
Overweight
- Body Fat
- Muscle Mass: improves
- Body Mass Index (BMI): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Body Fat No effect | NoneNo effect | 637 people | ||||
| Muscle Mass | Improves (the measure goes up) | 1 study | 637 people | |||
| Body Mass Index (BMI) | Improves (the measure goes down) | 637 people | ||||
| Weight | Improves (the measure goes down) | 637 people | ||||
Peripheral Arterial Disease
- Blood Flow
- Walking Ability: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood Flow No effect | NoneNo effect | 206 people | ||||
| Walking Ability | Improves (the measure goes up) | 1 study | 122 people |
Mental Resilience
- Anxiety Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms | Improves (the measure goes down) | 2 studies | 2,189 people |
Mood Improvement
- Anxiety Symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Anxiety Symptoms | Improves (the measure goes down) | 2 studies | 2,189 people |
Alzheimer’s Disease
- Cognition: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition | Improves (the measure goes up) | 1 study | 702 people |
Metabolic Health
- Glycemic Control: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Glycemic Control | Improves (the measure goes up) | 1 study | 618 people |
Schizophrenia
- Schizophrenia symptoms: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Schizophrenia symptoms | Improves (the measure goes down) | 1 study | 765 people |
Uremic Pruritus
- Itching: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Itching | Improves (the measure goes up) | 1 study | 370 people |
Alzheimer’s Disease
- Cognition: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Cognition | Improves (the measure goes up) | 1 study | 702 people |
What the published studies found
4 automated readings
LDL cholesterol
The studies read are too weak to tell whether Omega-3 Fatty Acids changes LDL cholesterol. The strongest review read studied people with type 2 diabetes mellitus. The evidence is very weak.
Possible harm: 3 studies read reported a worse result for LDL cholesterol with Omega-3 Fatty Acids. One abstract says: "Low density lipoprotein (LDL) cholesterol fell by 0.18 and 0.10 mmol/l, respectively, with the safflower-oil and linseed-oil diets, but rose by 0.24 mmol/l with the fish-oil diet (p less than 0.05)." Check the studies below, and ask a doctor or pharmacist if this applies to you.
6 studies counted of 11 read: 5 reviews and 1 trial (18 people in the trials).
- Meta-analysis, 2008; 23 studies, 1,075 people; people with type 2 diabetes mellitus: unclear: evidence too weak to tell (the review the verdict rests on).
LDL cholesterol levels were raised by 0.11 mmol/L
Omega-3 polyunsaturated fatty acids (PUFA) for type 2 diabetes mellitus - Meta-analysis, 2026; 18 studies; people with type 1 diabetes: no clear difference.
no effect on the other outcomes, including TC, LDL-C
Efficacy of Omega-3 Polyunsaturated Fatty Acid Supplementation on the Lipid and Glycemic Profile in Type 1 Diabetes: A Systematic Review and Meta-Analysis - Meta-analysis, 2025; 9 studies, 626 people: no clear difference. Effects of seal oil supplementation on lipid profile biomarkers: A systematic review and meta-analysis of randomized controlled trials
- Meta-analysis, 2021; 13 studies; patients with chronic kidney disease: no clear difference.
no significant effects on HDL, LDL
Effect of omega-3 fatty acids supplementation on cardio-metabolic and oxidative stress parameters in patients with chronic kidney disease: a systematic review and meta-analysis - Meta-analysis, 2007; 6 studies, 313 people; people with intermittent claudication: worsens.
increased (low-density lipoprotein) LDL cholesterol levels
Omega-3 fatty acids for intermittent claudication - Crossover trial, 1994; 18 people: no clear difference.
had no effect on fasting glucose, high-density lipoprotein cholesterol, or LDL-cholesterol levels
Effects of a small quantity of omega-3 fatty acids on cardiovascular risk factors in NIDDM. A randomized, prospective, double-blind, controlled study
- Meta-analysis, 2008; 23 studies, 1,075 people; people with type 2 diabetes mellitus: unclear: evidence too weak to tell (the review the verdict rests on).
Memory
The best available review (2025, 58 studies) found a large improvement in memory. 4 of the 6 studies read agree; 1 found no clear answer, 1 found mixed results. The evidence is moderate.
6 studies counted of 8 read: 5 reviews and 1 trial (72 people in the trials).
- Meta-analysis, 2025; 58 studies: improves (the review the verdict rests on). A systematic review and dose response meta analysis of Omega 3 supplementation on cognitive function
- Systematic review, 2022; 9 studies, 1,319 people: improves. Effects of Omega-3 Polyunsaturated Fatty Acids on Brain Functions: A Systematic Review
- Meta-analysis, 2020; 29 studies, 4,247 people; youths: mixed results.
beneficial effects of eicosapentaenoic acid (EPA)-rich
Omega-3 and its domain-specific effects on cognitive test performance in youths: A meta-analysis - Meta-analysis, 2020; 25 studies; non-demented adults, including mild cognitive impairment: improves.
only memory function showed a mild benefit
Long-chain omega-3 polyunsaturated fatty acids and cognitive decline in non-demented adults: a systematic review and meta-analysis - Systematic review, 2018; 7 studies; patients with Alzheimer's disease: unclear: evidence too weak to tell.
Most studies did not find statistically significant results
Omega-3 fatty acids' supplementation in Alzheimer's disease: A systematic review - Randomised trial, 2024; 72 people; first-diagnosed, drug-naïve depression outpatients: improves.
change of immediate memory at both week 4 and week 12 (p < 0.05)
Omega-3 polyunsaturated fatty acids supplementation improves memory in first-diagnosed, drug-naïve patients with depression: Secondary analysis of data from a randomized controlled trial
Sleep quality
The studies disagree. The best available review (2024, 8 studies) found an improvement in sleep quality, while 3 of the 8 studies read found no clear difference. The evidence is very weak.
8 studies counted of 11 read: 4 reviews and 4 trials (202 people in the trials).
- Meta-analysis, 2024; 8 studies: improves (the review the verdict rests on).
Subjectively assessed sleep was significantly improved by omega-3 LC-PUFA
Effect of omega-3 fatty acids on sleep: a systematic review and meta-analysis of randomized controlled trials - Systematic review, 2023; 9 studies; postmenopausal women: no clear difference.
sleep quality outcomes displayed heterogeneity across the studies
Effects of Omega-3 Polyunsaturated Fatty Acids Intake on Vasomotor Symptoms, Sleep Quality and Depression in Postmenopausal Women: A Systematic Review - Meta-analysis, 2021; 20 studies; infants, children, and adults: no clear difference.
No effectiveness was found in adults' total sleep duration, sleep latency, sleep efficiency, sleep quality
Omega-3 long-chain polyunsaturated fatty acid and sleep: a systematic review and meta-analysis of randomized controlled trials and longitudinal studies - Meta-analysis, 2018; 3 studies, 483 people; menopausal women experiencing vasomotor symptoms: no clear difference.
Meta-analysis of the data showed no difference in the frequency and severity of hot flushes, …
Effect of omega-3 supplements on vasomotor symptoms in menopausal women: A systematic review and meta-analysis - Randomised trial, 2025; patients with type 2 diabetes: improves.
fish oil supplementation enhances sleep parameters
Marine n-3 polyunsaturated fatty acids slow sleep impairment progression by regulating central circadian rhythms in type 2 diabetes - Randomised trial, 2022; 66 people; healthy Japanese males and females aged 45 years or older: improves.
factor III (frequent dreaming) scores among the OSA-MA scores were significantly improved
Effect of Docosahexaenoic Acid and Eicosapentaenoic Acid Supplementation on Sleep Quality in Healthy Subjects: A Randomized, Double-Blinded, Placebo-Controlled Trial - Randomised trial, 2021; 84 people; healthy young adults, low oily fish intake: improves.
improvements in actigraphy sleep efficiency (p = 0.030)
Differential Effects of DHA- and EPA-Rich Oils on Sleep in Healthy Young Adults: A Randomized Controlled Trial - Crossover trial, 2020; 52 people; hemodialysis patients with uremic pruritus: improves.
sleep quality scores were different in two groups
The effects of omega-3 on the sleep quality of patients with uremic pruritus undergoing hemodialysis: a randomized crossover study
- Meta-analysis, 2024; 8 studies: improves (the review the verdict rests on).
Stress
The studies read do not show a clear benefit for stress. One reading found mixed results, a second reading of the same search found little or no difference. The evidence is very weak.
4 studies counted of 11 read: 4 reviews.
- Meta-analysis, 2026; 11 studies; patients with diabetes: no clear difference (the review the verdict rests on).
Pooled analyses showed no significant effects on triglycerides, low-density or high-density lipoprotein cholesterol, glycated hemoglobin, …
Effectiveness of ω-3 Supplementation on Biochemical, Clinical, and Inflammatory Parameters in Patients with Diabetes: A Systematic Review and Meta-analysis - Meta-analysis, 2026; 41 studies; athletes and individuals undergoing exercise: improves.
delayed-onset muscle soreness (standardized mean difference = -0.4 to -0.7) were significantly and moderately reduced
Effects of Omega-3 Supplementation on Inflammation and Recovery in Sports: A Meta-Analysis - Systematic review, 2026; individuals with anxiety and depression: improves.
modest benefits of omega-3 supplementation for anxiety severity
From Plate to Mind: Scientific Perspectives on Foods That May Influence Anxiety and Depression - Meta-analysis, 2021; 13 studies; patients with chronic kidney disease: improves.
omega-3 FAs supplementation significantly decrease TC (SMD: -0.26; 95% CI: - 0.51, - 0.02; I2 …
Effect of omega-3 fatty acids supplementation on cardio-metabolic and oxidative stress parameters in patients with chronic kidney disease: a systematic review and meta-analysis
- Meta-analysis, 2026; 11 studies; patients with diabetes: no clear difference (the review the verdict rests on).
Key findings
- High-density lipoprotein (HDL)Improves (the measure goes up)
- C-Reactive Protein (CRP)Improves (the measure goes down)
- Depression SymptomsImproves (the measure goes down)
Shop the evidence-backed picks
Third-party tested Omega-3 Fatty Acids products, in the forms the graded studies used where we can match them.
- Grade B
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Studies cited
21 studies from PubMed
- Effects of omega-3 fatty acids on chronic pain: a systematic review and meta-analysis.
- Effect of omega-3 fatty acid supplementation on markers of inflammation and endothelial function in patients with chronic heart disease: A systematic review and meta-analysis.
- Efficacy and safety of omega-3 fatty acids supplementation for anxiety symptoms: a systematic review and dose-response meta-analysis of randomized controlled trials.
- Omega-3 fatty acids for depression in adults
- Effects of long-chain omega-3 polyunsaturated fatty acids on reducing anxiety and/or depression in adults; A systematic review and meta-analysis of randomised controlled trials
- Exploration of the optimized portrait of omega-3 polyunsaturated fatty acids in treating depression: A meta-analysis of randomized-controlled trials.
- Omega-3 for bipolar disorder: meta-analyses of use in mania and bipolar depression
- Omega-3 fatty acids for depression in adults
- Efficacy and Safety of Omega-3 Fatty Acids in Ameliorating Pruritus in Adult Patients With Chronic Kidney Disease: A Meta-Analysis of Randomized Controlled Trials.
- The effects of ω-3 fatty acids on inflammatory and oxidative stress markers in patients with Type 2 diabetes mellitus: A systematic review and meta-analysis of controlled trials.
- The Effect of Omega-3 Supplementation on Heart Failure Outcome: A Meta-Analysis of Randomized Clinical Trial.
- Cognitive efficacy of omega‑3 fatty acids in Alzheimer's disease: A systematic review and meta‑analysis.
- Omega-3 polyunsaturated fatty acid and insulin sensitivity: a meta-analysis of randomized controlled trials
- Effect of Omega-3 Fatty Acids on Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- Supplementation of Omega 3 during Pregnancy and the Risk of Preterm Birth: A Systematic Review and Meta-Analysis.
- The effect of omega-3 supplementation on metabolic, inflammatory and oxidative stress biomarkers in pregnant women: a systematic review and meta-analysis.
- Effect of omega-3 supplementation on lipid profile in children and adolescents: a systematic review and meta-analysis of randomized clinical trials.
- Influence of adjuvant omega-3-polyunsaturated fatty acids on depression, sleep, and emotion regulation among outpatients with major depressive disorders - Results from a double-blind, randomized and placebo-controlled clinical trial
- Effects of Long-Chain n-3 Fatty Acids Supplementation During Caloric Restriction on Body Composition in Overweight and Obese Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- The effectiveness of intervention with omega-3 fatty acids, eicosapentaenoic and docosahexenoic acid in peripheral arterial disease: a systematic review and meta-analysis.
- Effect of n-3 polyunsaturated fatty acids on the treatment of schizophrenia: an updated systematic review and meta-analysis.