Supplement
Flaxseed is a fiber-rich seed that contains plant compounds called lignans, which have weak estrogen-like activity in the body. People mostly look at it for menopausal hot flashes, though the evidence for that use is limited. Its better-supported results came from type 2 diabetes, where moderate evidence from trial reviews found blood glucose improved, although the effect was small.
Sources: PMID 29228348; PMID 36640581
- Updated
- How we grade
- 22 studies cited
- Best evidence
- Grade B
- Conditions studied
- 14
- Outcomes
- 85
- Graded outcomes
- 0247
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
Obesity
- Blood glucose: improves
- Adiponectin
- C-Reactive Protein (CRP): improves
High Cholesterol
- Blood glucose: improves
- C-Reactive Protein (CRP): improves
- Triglycerides: improves
Coronary Artery Disease (CAD)
- Blood glucose: improves
- C-Reactive Protein (CRP): improves
- Triglycerides: improves
Endometriosis
- Dysmenorrhea Symptoms: improves
- Dyspareunia: improves
- Pain: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Dysmenorrhea Symptoms Moderate Improvement | Improves (the measure goes down) | Moderate effect | 1 study | 102 people | ||
Studies that measured dysmenorrhea symptoms | ||||||
| Dyspareunia | Improves (the measure goes up) | 102 people | ||||
| Pain | Improves (the measure goes down) | 102 people | ||||
Overweight
- Adiponectin
- C-Reactive Protein (CRP): improves
- Blood glucose: improves
Prediabetes
- Adiponectin
- Blood glucose: improves
- Leptin: improves
Metabolic Syndrome
- Adiponectin
- C-Reactive Protein (CRP): improves
- Leptin: improves
Gestational Diabetes
- Glutathione (GSH)
- Total Antioxidant Capacity (TAC): improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Glutathione (GSH) No effect | NoneNo effect | 429 people | ||||
| Total Antioxidant Capacity (TAC) | Improves (the measure goes up) | 1 study | 429 people | |||
Studies that measured total antioxidant capacity (tac) | ||||||
Hormone Health
- DHEAS
- Testosterone: improves
- Follicle-Stimulating Hormone: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| DHEAS No effect | NoneNo effect | 629 people | ||||
| Testosterone | Improves (the measure goes up) | 1 study | 629 people | |||
Studies that measured testosterone | ||||||
| Follicle-Stimulating Hormone | Improves (the measure goes up) | 629 people | ||||
| Sex Hormone Binding Globulin | Improves (the measure goes up) | 629 people | ||||
Metabolic Health
- Adiponectin
- Leptin: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Adiponectin No effect | NoneNo effect | 284 people | ||||
| Leptin | Improves (the measure goes up) | 2 studies | 284 people | |||
Studies that measured leptin
| ||||||
High Blood Pressure
- Blood Pressure: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood Pressure | Improves (the measure goes down) | 4 studies | 1,209 people |
General Cardiovascular Health
- Blood Pressure: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Blood Pressure | Improves (the measure goes down) | 4 studies | 1,209 people |
Key findings
- Blood glucoseImproves (the measure goes down)
- Apolipoprotein AImproves (the measure goes down)
- Dysmenorrhea SymptomsImproves (the measure goes down)
Shop the evidence-backed picks
Third-party tested Flaxseed products, in the forms the graded studies used where we can match them.
- Grade B
Links to Fullscript, iHerb or Thorne carry our referral, so we may earn a commission at no extra cost to you. Grades come from the research and never change based on what we earn. Fullscript asks for a free account before it shows its catalog and prices. Full disclosure
Studies cited
22 studies from PubMed
- Effects of Flaxseed Interventions on Circulating Inflammatory Biomarkers: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- Impact of flaxseed supplementation on plasma lipoprotein(a) concentrations: A systematic review and meta-analysis of randomized controlled trials.
- Flaxseed Oil Supplementation Augments Antioxidant Capacity and Alleviates Oxidative Stress: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- Effect of flaxseed supplementation on markers of inflammation and endothelial function: A systematic review and meta-analysis.
- Effects of flaxseed supplementation on weight loss, lipid profiles, glucose, and high-sensitivity C-reactive protein in patients with coronary artery disease: A systematic review and meta-analysis of randomized controlled trials.
- Meta-analysis of the effects of flaxseed interventions on blood lipids
- Effects of Flaxseed on Blood Lipids in Healthy and Dyslipidemic Subjects: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- Effect of flaxseed supplementation on lipid profile: An updated systematic review and dose-response meta-analysis of sixty-two randomized controlled trials.
- The effects of flaxseed (Linum usitatissimum) supplementation on anthropometric indices: An updated systematic review and meta-analysis of randomized clinical trials.
- The effect of flaxseed supplementation on body weight and body composition: a systematic review and meta-analysis of 45 randomized placebo-controlled trials.
- Can flaxseed supplementation affect circulating adipokines in adults? An updated systematic review and meta-analysis of randomized controlled trials.
- The effect of flaxseed supplementation on circulating adiponectin and leptin concentration in adults: A systematic review and meta-analysis of randomized controlled trials.
- Flaxseed supplementation on glucose control and insulin sensitivity: a systematic review and meta-analysis of 25 randomized, placebo-controlled trials.
- Flaxseed supplementation significantly reduces hemoglobin A1c in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.
- Effect of flaxseed (Linum usitatissimum) supplementation on glycemic control and insulin resistance in prediabetes and type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials.
- Can flaxseed supplementation alleviate blood pressure in patients with metabolic diseases? Evaluating the strength of evidence using a meta-analysis and GRADE approach.
- Effect of flaxseed supplementation on blood pressure: a systematic review, and dose-response meta-analysis of randomized clinical trials.
- Flaxseed consumption may reduce blood pressure: a systematic review and meta-analysis of controlled trials.
- Flaxseed Lowers Blood Pressure in Hypertensive Subjects: A Meta-Analysis of Randomized Controlled Trials.
- The effect of flaxseed supplementation on sex hormone profile in adults: a systematic review and meta-analysis.
- Effects of flaxseed oil supplementation on biomarkers of inflammation and oxidative stress in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized controlled trials.
- The Effects of Chamomile and Flaxseed on Pelvic Pain, Dyspareunia, and Dysmenorrhea in Endometriosis: A Controlled Randomized Clinical Trial.