Flaxseed Oil
Flaxseed oil is rich in ALA omega-3. Conversion to EPA/DHA is limited and clinical effects vary by outcome.
Overview
What is flaxseed oil?
Flaxseed oil is a good source of omega-3 fatty acids. This article refers to flaxseed oil, not whole or ground flaxseed as food. See Flaxseed for more info.
Dosage
A typical dose of flaxseed oil is 1-2 ml per day.
Higher doses have been used in the short term (24 grams for 7 weeks).
Effect graph
Effect heatmap
SupplementDEX Database
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Database Snapshot
Most flaxseed oil research is concentrated in a handful of conditions.
- High cholesterol (Hyperlipidemia) accounts for 17 of 66 studies (26%).
- Prostate cancer accounts for 9 of 66 studies (14%).
- Diabetes accounts for 8 of 66 studies (12%).
- Sparse coverage remains for Breast cancer, Cardiovascular disease, Parkinson's disease.
Safety
Oral flaxseed oil is likely safe when used at a dose of up to 2 grams daily for up to 6 months. Higher doses of up to 24 grams per day have been safely used for up to 7 weeks.
Frequently Asked Questions
References
Sources60 references
SupplementDEX uses only high-quality sources to determine supplement effectiveness.
SupplementDEX Database · Bipolar disorder
1 reference1.SupplementDEX Database: Bipolar disorder — Randomized, placebo-controlled trial of flax oil in pediatric bipolar disorder2010
In 51 youths with bipolar disorder over 16 weeks, flax oil up to 6.6 g alpha-LNA/day did not significantly change mania or depression rating scales versus olive oil, though higher omega-3 status correlated with lower symptom severity.
2.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Flaxseed supplementation significantly reduces hemoglobin A1c in patients with type 2 diabetes mellitus: A systematic review and meta-analysis2023
A meta-analysis of 13 T2DM trials found flaxseed supplementation significantly lowered HbA1c versus control, without consistent effects on weight, blood pressure, fasting glucose, or lipids overall.
3.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Comparisons of the effects of different flaxseed products consumption on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases: systematic review and a dose-response meta-analysis of randomized controlled trials2021
A dose-response meta-analysis of 31 RCTs (1,698 participants) found flaxseed products lowered total cholesterol, LDL, triglycerides, apoB, and IL-6 in dyslipidemia-related disease, with whole flaxseed showing strongest effects.
4.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Effects of Flaxseed on Blood Lipids in Healthy and Dyslipidemic Subjects: A Systematic Review and Meta-Analysis of Randomized Controlled Trials2021
A meta-analysis of 14 RCTs (1,107 participants) found flaxseed significantly lowered total cholesterol, LDL, and triglycerides in dyslipidemic patients; healthy subjects showed HDL increases without LDL reduction.
5.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Effect of flaxseed supplementation on lipid profile: An updated systematic review and dose-response meta-analysis of sixty-two randomized controlled trials2020
An updated meta-analysis of 62 flaxseed RCTs (3,772 participants) found supplementation significantly reduced total cholesterol (−5.4 mg/dL), triglycerides (−9.4 mg/dL), and LDL (−4.2 mg/dL).
6.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Effect of flaxseed oil supplementation on anthropometric and metabolic indices in patients with coronary artery disease: A double-blinded randomized controlled trial2019
In 44 CAD patients over 10 weeks, 5 g/day flaxseed oil (2.5 g ALA) lowered diastolic blood pressure and triglycerides versus milk placebo, without between-group changes in weight or BMI.
7.SupplementDEX Database: High cholesterol (Hyperlipidemia) — DHA-enriched high-oleic acid canola oil improves lipid profile and lowers predicted cardiovascular disease risk in the canola oil multicenter randomized controlled trial2014
In 130 adults with abdominal obesity in a 5-diet crossover, DHA-enriched high-oleic canola oil improved lipid profiles and predicted 10-year CVD risk compared with conventional canola and other test oils.
8.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Omega-3 fatty acids and lipoprotein associated phospholipase A(2) in healthy older adult males and females2011
In 59 healthy adults ≥50 over 8 weeks, ~11 g/day flaxseed or fish oil did not significantly change lipoprotein-associated phospholipase A2 mass or activity versus olive oil control.
9.SupplementDEX Database: High cholesterol (Hyperlipidemia) — High-oleic rapeseed (canola) and flaxseed oils modulate serum lipids and inflammatory biomarkers in hypercholesterolaemic subjects2010
In 36 hypercholesterolemic adults over 28 days per diet, high-oleic canola blended with flaxseed oil lowered LDL cholesterol 15.1% and total cholesterol 11% versus a Western diet.
10.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Meta-analysis of the effects of flaxseed interventions on blood lipids2009
A meta-analysis of 28 flaxseed trials found whole flaxseed and lignans reduced total and LDL cholesterol (~0.10–0.28 mmol/L), while flaxseed oil alone did not significantly change lipids.
11.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Flaxseed oil supplementation increases plasma F1-phytoprostanes in healthy men2009
In 36 healthy men over 4 weeks, flaxseed oil 9 g/day (5.4 g ALA) raised plasma ALA and F1-phytoprostanes versus olive oil, without changing F2-isoprostanes.
12.SupplementDEX Database: High cholesterol (Hyperlipidemia) — A comparison of fish oil, flaxseed oil and hempseed oil supplementation on selected parameters of cardiovascular health in healthy volunteers2008
In 86 healthy volunteers over 12 weeks, 2 g/day fish oil raised plasma EPA/DHA, flaxseed oil transiently raised ALA, and none of the oils significantly changed standard lipid panels versus placebo.
13.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Flaxseed oil supplementation does not affect plasma lipoprotein concentration or particle size in human subjects2006
In 56 adults over 26 weeks, 3 g/day ALA from flaxseed oil did not lower LDL, HDL, or triglycerides versus olive oil; total cholesterol was 0.45 mmol/L higher with flaxseed oil (P=0.026).
14.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Influence of alpha-linolenic acid and fish-oil on markers of cardiovascular risk in subjects with an atherogenic lipoprotein phenotype2005
In 57 men with atherogenic lipoprotein phenotype over 12 weeks, flaxseed oil lowered total cholesterol 12.3% and fish oil lowered triglycerides 23% and small dense LDL 22%, with diet-specific lipid effects.
15.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Dietary alpha-linolenic acid decreases C-reactive protein, serum amyloid A and interleukin-6 in dyslipidaemic patients2003
In 76 dyslipidemic men over 3 months, 15 mL/day linseed oil lowered CRP 38%, serum amyloid A 23%, and IL-6 10.5% versus safflower oil, independent of lipid changes.
16.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Omega-3 fatty acid intake results in a relationship between the fatty acid composition of LDL cholesterol ester and LDL cholesterol content in humans1997
In 26 adults in a crossover feeding study, fish oil supplementation correlated EPA/DHA in LDL cholesteryl esters with LDL cholesterol content; this association was absent with olive or flaxseed oil periods.
17.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Normal subjects consuming physiological levels of 18:3(n-3) and 20:5(n-3) from flaxseed or fish oils have characteristic differences in plasma lipid and lipoprotein fatty acid levels1996
In healthy adults over 3 months at low n-3 doses, fish oil reduced plasma triglycerides and enriched lipoprotein EPA/DHA, while flaxseed oil raised ALA with minimal change in long-chain n-3 or cholesterol.
18.SupplementDEX Database: High cholesterol (Hyperlipidemia) — Dietary alpha-linolenic acid alters tissue fatty acid composition, but not blood lipids, lipoproteins or coagulation status in humans1993
In 10 healthy men fed controlled diets 126 days, a high-ALA flaxseed oil diet altered serum and mononuclear cell fatty acids but did not change serum lipids, lipoproteins, or coagulation tests versus basal diet.
SupplementDEX Database · Obesity
1 reference19.SupplementDEX Database: Obesity — The effect of flaxseed supplementation on body weight and body composition: a systematic review and meta-analysis of 45 randomized placebo-controlled trials2017
A meta-analysis of 45 flaxseed RCTs found supplementation reduced body weight 0.99 kg, BMI 0.30 kg/m², and waist circumference 0.80 cm versus control, with larger effects at ≥30 g/day whole flaxseed.
20.SupplementDEX Database: Rheumatoid arthritis — Alpha-linolenic acid in the treatment of rheumatoid arthritis. A double-blind, placebo-controlled and randomized study: flaxseed vs. safflower seed1995
Double-blind RCT in 22 rheumatoid arthritis patients found 3-month alpha-linolenic acid from flaxseed did not improve joint scores or inflammatory markers versus safflower seed.
SupplementDEX Database · Atherosclerosis
2 references21.SupplementDEX Database: Atherosclerosis — A comparison between the effects of flaxseed oil and fish oil supplementation on cardiovascular health in type 2 diabetic patients with coronary heart disease: A randomized, double-blinded, placebo-controlled trial2019
In 90 T2DM patients with CHD over 12 weeks, 2,000 mg/day fish oil or flaxseed oil both reduced insulin and raised total antioxidant capacity versus placebo, with flaxseed also lowering hs-CRP.
22.SupplementDEX Database: Atherosclerosis — Dietary linolenic acid is inversely associated with calcified atherosclerotic plaque in the coronary arteries: the National Heart, Lung, and Blood Institute Family Heart Study2005
Observational study of 2004 adults aged 32-93 found higher dietary linolenic acid intake inversely associated with coronary artery calcification in a dose-response pattern.
23.SupplementDEX Database: Attention deficit hyperactivity disorder — Supplementation with flax oil and vitamin C improves the outcome of Attention Deficit Hyperactivity Disorder (ADHD)2005
In children with ADHD, flax oil plus vitamin C raised RBC membrane fatty acids and significantly reduced total hyperactivity scores on the ADHD rating scale versus control.
SupplementDEX Database · Breast cancer
2 references24.SupplementDEX Database: Breast cancer — Low alpha-linolenic acid content of adipose breast tissue is associated with an increased risk of breast cancer2000
In 123 breast cancer cases versus 59 benign controls in France, lower adipose breast tissue alpha-linolenic acid was associated with increased invasive breast carcinoma risk in adjusted analyses.
25.SupplementDEX Database: Breast cancer — alpha-Linolenic acid content of adipose breast tissue: a host determinant of the risk of early metastasis in breast cancer1994
In 121 localized breast cancer patients followed ~31 months, low adipose alpha-linolenic acid predicted early visceral metastasis along with large tumor size in multivariate analysis.
SupplementDEX Database · Burns
1 reference26.SupplementDEX Database: Burns — The effect of isolated soy protein adjunctive with flaxseed oil on markers of inflammation, oxidative stress, acute phase proteins, and wound healing of burn patients; a randomized clinical trial2017
In 73 burn patients (20–50% TBSA) over 3 weeks, isolated soy protein plus flaxseed oil reduced hs-CRP and ferritin and increased albumin versus wheat flour plus corn oil control.
SupplementDEX Database · Cardiovascular disease
2 references27.SupplementDEX Database: Cardiovascular disease — Interplay between different polyunsaturated fatty acids and risk of coronary heart disease in men2005
In 45,722 men followed 14 years, long-chain and intermediate-chain n-3 PUFA intakes were each associated with lower coronary heart disease risk, including sudden death, independent of n-6 intake.
28.SupplementDEX Database: Cardiovascular disease — Dietary alpha-linolenic acid is associated with reduced risk of fatal coronary heart disease, but increased prostate cancer risk: a meta-analysis2004
A meta-analysis found high dietary alpha-linolenic acid associated with lower fatal CHD risk (RR 0.79) but higher prostate cancer risk (RR 1.70, 95% CI 1.12–2.58) in observational studies.
29.SupplementDEX Database: Carpal tunnel syndrome — Effect of Linum usitatissimum L. (linseed) oil on mild and moderate carpal tunnel syndrome: a randomized, double-blind, placebo-controlled clinical trial2014
In 100 mild-to-moderate carpal tunnel patients over 4 weeks, topical linseed oil plus night splinting improved Boston Questionnaire symptom and function scores and nerve conduction versus topical placebo.
30.SupplementDEX Database: Cognitive performance — Supplementation with Flaxseed Oil Rich in Alpha-Linolenic Acid Improves Verbal Fluency in Healthy Older Adults2023
12-week RCT in 60 healthy older adults given 2.2 g/day ALA from flaxseed oil found verbal fluency improved versus corn oil placebo; other cognitive tests did not differ.
SupplementDEX Database · Diabetes
6 references31.SupplementDEX Database: Diabetes — The effects of n-3 fatty acids from flaxseed oil on genetic and metabolic profiles in patients with gestational diabetes mellitus: a randomised, double-blind, placebo-controlled trial2020
In 60 women with gestational diabetes over 6 weeks, 2,000 mg/day flaxseed oil n-3s lowered fasting glucose, insulin, HOMA-IR, and triglycerides and modulated PPAR-gamma and inflammatory gene expression versus placebo.
32.SupplementDEX Database: Diabetes — Flaxseed supplementation on glucose control and insulin sensitivity: a systematic review and meta-analysis of 25 randomized, placebo-controlled trials2018
A meta-analysis of 25 flaxseed RCTs found supplementation significantly reduced fasting glucose (−2.94 mg/dL), insulin, and HOMA-IR and increased insulin sensitivity, without significant HbA1c change.
33.SupplementDEX Database: Diabetes — Clinical and metabolic response to flaxseed oil omega-3 fatty acids supplementation in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial2017
In 60 grade-3 diabetic foot ulcer patients over 12 weeks, flaxseed oil omega-3s 2,000 mg/day reduced ulcer dimensions and improved insulin, HOMA-IR, and HbA1c versus placebo.
34.SupplementDEX Database: Diabetes — A randomized-controlled clinical trial investigating the effect of omega-3 fatty acids and vitamin E co-supplementation on markers of insulin metabolism and lipid profiles in gestational diabetes2015
In 60 gestational diabetes patients over 6 weeks, 1,000 mg omega-3 from flaxseed oil plus 400 IU vitamin E lowered fasting glucose, insulin, and HOMA-IR significantly versus placebo.
35.SupplementDEX Database: Diabetes — Dietary milled flaxseed and flaxseed oil improve N-3 fatty acid status and do not affect glycemic control in individuals with well-controlled type 2 diabetes2010
In 34 type 2 diabetes patients over 12 weeks, milled flaxseed 32 g/day or flaxseed oil 13 g/day (~7.4 g ALA) raised plasma n-3 status without changing HbA1c, glucose, insulin, or adipokines versus control bakery products.
36.SupplementDEX Database: Diabetes — High dose flaxseed oil supplementation may affect fasting blood serum glucose management in human type 2 diabetics2008
In adults with type 2 diabetes, ~10 g/day flaxseed oil (~5.5 g ALA) for 3 months did not change fasting glucose, insulin, or HbA1c versus safflower oil placebo.
37.SupplementDEX Database: Elderly physical function — Alpha-linolenic acid supplementation and resistance training in older adults2009
In 51 older adults resistance training 12 weeks, flax oil ~14 g/day ALA lowered IL-6 in men and combined with training improved strength, lean mass, and bone density versus placebo.
38.SupplementDEX Database: Endometrial hyperplasia — Effects of Flaxseed Oil Omega-3 Fatty Acids Supplementation on Regression and Metabolic Status in Endometrial Hyperplasia: A randomized, Double-Blind, Placebo-Controlled Trial2019
In 40 women with simple endometrial hyperplasia over 12 weeks, flaxseed oil omega-3s 2,000 mg/day improved metabolic markers and increased endometrial lesion regression versus placebo.
SupplementDEX Database · Hypertension
5 references39.SupplementDEX Database: Hypertension — Effect of flaxseed supplementation on blood pressure: a systematic review, and dose-response meta-analysis of randomized clinical trials2023
A meta-analysis of 33 trials (2,427 participants) found flaxseed supplementation reduced systolic BP by 3.19 mmHg and diastolic BP by 1.96 mmHg, with larger effects at higher doses and longer duration.
40.SupplementDEX Database: Hypertension — The effect of flaxseed oil consumption on blood pressure among patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized clinical trials2022
A meta-analysis of 5 trials in metabolic syndrome found flaxseed oil reduced systolic blood pressure by 3.86 mmHg (p=0.04) but did not significantly change diastolic BP versus control.
41.SupplementDEX Database: Hypertension — Effects of flaxseed supplements on blood pressure: A systematic review and meta-analysis of controlled clinical trial2015
A meta-analysis of 15 flaxseed trials (1,302 participants) found supplementation reduced systolic BP 2.85 mmHg and diastolic BP 2.39 mmHg, with greater effects in trials ≥12 weeks.
42.SupplementDEX Database: Hypertension — Effects of diets high in walnuts and flax oil on hemodynamic responses to stress and vascular endothelial function2010
In hypercholesterolemic adults, diets enriched with walnuts and flax oil (6.5% ALA energy) improved flow-mediated dilation and blunted blood pressure and stress hormone responses to acute stress versus average American diet.
43.SupplementDEX Database: Hypertension — Dietary linolenic acid is associated with a lower prevalence of hypertension in the NHLBI Family Heart Study2005
Observational study of 4594 adults linked higher dietary linolenic acid to lower hypertension prevalence and lower systolic blood pressure.
SupplementDEX Database · Mastalgia
1 reference44.SupplementDEX Database: Mastalgia — The comparison of the effect of flaxseed oil and vitamin E on mastalgia and nodularity of breast fibrocystic: a randomized double-blind clinical trial2021
In 100 women with fibrocystic breast disease over 2 months, flaxseed oil and vitamin E 200 IU twice daily each reduced breast pain and nodularity within groups, without significant between-group differences.
SupplementDEX Database · Metabolic syndrome
1 reference45.SupplementDEX Database: Metabolic syndrome — A Comparative Study of the Effect of Flaxseed Oil and Sunflower Oil on the Coagulation Score, Selected Oxidative and Inflammatory Parameters in Metabolic Syndrome Patients2020
In 52 metabolic syndrome patients over 7 weeks, 25 mL/day flaxseed oil versus sunflower oil significantly lowered serum IL-6 but did not differ on coagulation score or total antioxidant capacity.
46.SupplementDEX Database: Nonalcoholic fatty liver disease (NAFLD) — Flaxseed oil in the context of a weight loss programme ameliorates fatty liver grade in patients with non-alcoholic fatty liver disease: a randomised double-blind controlled trial2020
In 68 NAFLD patients on a hypocaloric diet for 12 weeks, 20 g/day flaxseed oil reduced fatty liver grade more than sunflower oil (−0.68 vs −0.29, P=0.002) alongside liver enzyme improvements.
SupplementDEX Database · Parkinson's disease
2 references47.SupplementDEX Database: Parkinson's disease — The effects of omega-3 fatty acids and vitamin E co-supplementation on clinical and metabolic status in patients with Parkinson's disease: A randomized, double-blind, placebo-controlled trial2017
In 60 Parkinson's disease patients over 12 weeks, flaxseed omega-3 1,000 mg plus vitamin E 400 IU improved UPDRS scores and raised antioxidant capacity while lowering hs-CRP versus placebo.
48.SupplementDEX Database: Parkinson's disease — The clinically important difference on the unified Parkinson's disease rating scale2009
In 653 Parkinson's patients, distribution- and anchor-based analyses estimated minimal clinically important UPDRS motor score changes of ~2.5 points (minimal), ~5.2 (moderate), and ~10.8 (large).
SupplementDEX Database · Pneumonia
1 reference49.SupplementDEX Database: Pneumonia — Intake of n-6 and n-3 fatty acids and fish and risk of community-acquired pneumonia in US men2005
10-year cohort of 38,378 men aged 44-79 found higher alpha-linolenic and linoleic acid intake associated with lower community-acquired pneumonia risk.
50.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — The Effects of Flaxseed Oil Omega-3 Fatty Acids Supplementation on Metabolic Status of Patients with Polycystic Ovary Syndrome: A Randomized, Double-Blind, Placebo-Controlled Trial2017
In 60 women with PCOS over 12 weeks, flaxseed oil omega-3s 2,000 mg/day lowered insulin, HOMA-IR, hirsutism scores, and triglycerides versus placebo.
51.SupplementDEX Database: Polycystic ovary syndrome (PCOS) — Metabolic and endocrine effects of long-chain versus essential omega-3 polyunsaturated fatty acids in polycystic ovary syndrome2011
In 51 women with PCOS over 6 weeks, 3.5 g/day fish oil or flaxseed oil both lowered triglycerides; fish oil worsened some glucose tolerance indices versus soybean oil placebo.
SupplementDEX Database · Prostate cancer
8 references52.SupplementDEX Database: Prostate cancer — A prospective study of polyunsaturated fatty acid levels in blood and prostate cancer risk2007
In a nested case-control of 476 men followed 13 years, higher blood long-chain n-3 fatty acids were inversely associated with overall prostate cancer risk (RR Q5 vs Q1 0.59, P trend=0.01).
53.SupplementDEX Database: Prostate cancer — Dietary intake of n-3 and n-6 fatty acids and the risk of prostate cancer2004
In 47,866 US men followed 14 years, higher ALA from nonanimal sources was linked to advanced prostate cancer (RR 2.02 top vs bottom quintile), while EPA+DHA intakes were associated with lower total and advanced prostate cancer risk.
54.SupplementDEX Database: Prostate cancer — Dietary fat intake and prostate cancer risk: a case-control study in Spain2000
In a Spanish case-control study of 217 prostate cancer cases and 434 controls, higher alpha-linolenic acid intake increased prostate cancer risk in upper quartiles after adjusting for energy and covariates.
55.SupplementDEX Database: Prostate cancer — Alpha-linolenic acid and risk of prostate cancer: a case-control study in Uruguay2000
In a Uruguayan case-control study of 217 advanced prostate cancer cases and 431 matched controls, highest-quartile alpha-linolenic acid intake was associated with nearly 4-fold higher prostate cancer odds after adjustment for calories and other fats.
56.SupplementDEX Database: Prostate cancer — Serum linoleic and total polyunsaturated fatty acids in relation to prostate and other cancers: a population-based cohort study2000
In a Finnish cohort of 2,002 middle-aged men followed 12.6 years, upper-third serum linoleic acid and total polyunsaturated fatty acids were associated with about 70% lower prostate cancer risk than the lowest third.
57.SupplementDEX Database: Prostate cancer — Dietary fat and prostate cancer: current status1999
A narrative review concluded that dietary fat may relate to prostate cancer risk, but the specific fatty acid components responsible remain unclear despite decades of epidemiologic and animal research.
58.SupplementDEX Database: Prostate cancer — Prediagnostic level of fatty acids in serum phospholipids: omega-3 and omega-6 fatty acids and the risk of prostate cancer1997
In 141 matched Norwegian blood-donor pairs, higher prediagnostic alpha-linolenic acid in serum phospholipids was associated with increased prostate cancer risk, while higher linoleic-to-ALA ratios were inversely associated.
59.SupplementDEX Database: Prostate cancer — A prospective study of dietary fat and risk of prostate cancer1993
In the Health Professionals Follow-up Study of 51,529 U.S. men (ages 40–75), total and animal fat—especially from red meat—were associated with higher advanced prostate cancer risk; alpha-linolenic acid remained significant in multivariate models.
SupplementDEX Database · Ulcerative colitis
1 reference60.SupplementDEX Database: Ulcerative colitis — Effects of flaxseed and flaxseed oil supplement on serum levels of inflammatory markers, metabolic parameters and severity of disease in patients with ulcerative colitis2019
In a 12-week RCT of 75 ulcerative colitis patients, 30 g/day ground flaxseed or 10 g/day flaxseed oil reduced fecal calprotectin, inflammatory markers, blood pressure, and disease severity versus control.