Supplement

Grape Seed Extract

Grape seed extract is a concentrated source of proanthocyanidins, plant compounds from grape seeds that act as antioxidants and help keep small blood vessel walls firm. People mostly look at it for vein problems such as chronic venous insufficiency, where the evidence is moderate. Beyond veins, studies found blood pressure improved and blood flow went up, though the blood flow work involved only a few dozen people.

Sources: PMID 21802563; PMID 15577189

Updated 30 September 2026
How we grade
11 studies cited

Best evidence: Grade B
Conditions studied: 8
Outcomes: 37
Graded outcomes: 0251

Evidence by condition

Strong
Moderate
Limited
Very limited

8 conditions

General Cardiovascular Health

General Cardiovascular Health: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Blood Pressure Small Improvement	Improves (the measure goes down)	Small effect	1 study	252 people
Studies that measured blood pressure The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trialsJ Am Diet Assoc · PMID 21802563
	Blood Flow Moderate Increase	Improves (the measure goes up)	Moderate effect	2 studies	17 people
Studies that measured blood flow Effect of Grape Seed Extract and Quercetin on Cardiovascular and Endothelial Parameters in High-Risk SubjectsJ Biomed Biotechnol · PMID 15577189 Effects of grape seed extract consumption on platelet function in postmenopausal womenThromb Res · PMID 17950783
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	24 people
Studies that measured high-density lipoprotein (hdl) Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
	Leg Edema	Changes; see studies		1 study	8 people
Studies that measured leg edema Proanthocyanidin-rich grape seed extract reduces leg swelling in healthy women during prolonged sittingJ Sci Food Agric · PMID 22752876
	Oxidative Stress Biomarkers	Improves (the measure goes down)		1 study	24 people
Studies that measured oxidative stress biomarkers An evaluation of the antioxidant activity of a standardized grape seed extract, LeucoselectJ Clin Pharm Ther · PMID 9875688
	Triglycerides	Improves (the measure goes down)		1 study	24 people
	Heart Rate	Improves (the measure goes down)			156 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			24 people
	Total cholesterol	Improves (the measure goes down)			24 people

Dyslipidemia

Dyslipidemia: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Blood Pressure Small Improvement	Improves (the measure goes down)	Small effect	1 study	252 people
Studies that measured blood pressure The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trialsJ Am Diet Assoc · PMID 21802563
	Heart Rate	Improves (the measure goes down)			156 people

Cardiovascular Disease

Blood Flow: improves
C-Reactive Protein (CRP): improves
High-density lipoprotein (HDL): improves

Cardiovascular Disease: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Blood Flow Moderate Increase	Improves (the measure goes up)	Moderate effect	2 studies	36 people
Studies that measured blood flow Effect of Grape Seed Extract and Quercetin on Cardiovascular and Endothelial Parameters in High-Risk SubjectsJ Biomed Biotechnol · PMID 15577189 Effects of grape seed extract consumption on platelet function in postmenopausal womenThromb Res · PMID 17950783
	C-Reactive Protein (CRP)	Improves (the measure goes down)		1 study	32 people
Studies that measured c-reactive protein (crp) Effects of grape seed extract in Type 2 diabetic subjects at high cardiovascular risk: a double blind randomized placebo controlled trial examining metabolic markers, vascular tone, inflammation, oxidative stress and insulin sensitivityDiabet Med · PMID 19646193
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	32 people
Studies that measured high-density lipoprotein (hdl) Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
	Oxidative Stress Biomarkers	Improves (the measure goes down)		1 study	32 people
Studies that measured oxidative stress biomarkers An evaluation of the antioxidant activity of a standardized grape seed extract, LeucoselectJ Clin Pharm Ther · PMID 9875688
	Triglycerides	Improves (the measure goes down)		1 study	32 people
Studies that measured triglycerides Effect of grape seed extract on blood pressure in subjects with the metabolic syndromeMetabolism · PMID 19608210
	Total cholesterol	Improves (the measure goes down)			32 people

Metabolic Health

Food Intake: improves
High-density lipoprotein (HDL): improves
Oxidative Stress Biomarkers: improves

Metabolic Health: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Food Intake Small Decrease	Improves (the measure goes down)	Small effect	1 study	51 people
Studies that measured food intake The effect of grape-seed extract on 24 h energy intake in humansEur J Clin Nutr · PMID 15042136
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	24 people
Studies that measured high-density lipoprotein (hdl) Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
	Oxidative Stress Biomarkers	Improves (the measure goes down)		1 study	44 people
Studies that measured oxidative stress biomarkers An evaluation of the antioxidant activity of a standardized grape seed extract, LeucoselectJ Clin Pharm Ther · PMID 9875688
	Triglycerides	Improves (the measure goes down)		1 study	24 people
Studies that measured triglycerides Effect of grape seed extract on blood pressure in subjects with the metabolic syndromeMetabolism · PMID 19608210
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			24 people
	Total cholesterol	Improves (the measure goes down)			24 people

Type 2 Diabetes

C-Reactive Protein (CRP): improves
High-density lipoprotein (HDL): improves
Oxidative Stress Biomarkers: improves

Type 2 Diabetes: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	C-Reactive Protein (CRP) Small Decrease	Improves (the measure goes down)	Small effect	1 study	32 people
Studies that measured c-reactive protein (crp) Effects of grape seed extract in Type 2 diabetic subjects at high cardiovascular risk: a double blind randomized placebo controlled trial examining metabolic markers, vascular tone, inflammation, oxidative stress and insulin sensitivityDiabet Med · PMID 19646193
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	32 people
Studies that measured high-density lipoprotein (hdl) Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
	Oxidative Stress Biomarkers	Improves (the measure goes down)		1 study	32 people
Studies that measured oxidative stress biomarkers An evaluation of the antioxidant activity of a standardized grape seed extract, LeucoselectJ Clin Pharm Ther · PMID 9875688
	Triglycerides	Improves (the measure goes down)		1 study	32 people
Studies that measured triglycerides Effect of grape seed extract on blood pressure in subjects with the metabolic syndromeMetabolism · PMID 19608210
	Total cholesterol	Improves (the measure goes down)			32 people

Metabolic Syndrome

Blood Pressure: improves
High-density lipoprotein (HDL): improves
Triglycerides: improves

Metabolic Syndrome: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Blood Pressure Small Improvement	Improves (the measure goes down)	Small effect	1 study	27 people
Studies that measured blood pressure The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trialsJ Am Diet Assoc · PMID 21802563
	High-density lipoprotein (HDL)	Improves (the measure goes up)		1 study	27 people
Studies that measured high-density lipoprotein (hdl) Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
	Triglycerides	Improves (the measure goes down)		1 study	27 people
Studies that measured triglycerides Effect of grape seed extract on blood pressure in subjects with the metabolic syndromeMetabolism · PMID 19608210
	LDL Oxidation	Improves (the measure goes down)			27 people
	Low-density lipoprotein (LDL)	Improves (the measure goes down)			27 people
	Total cholesterol	Improves (the measure goes down)			27 people

Breast Cancer

Estrogen
Testosterone: improves

Breast Cancer: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People
	Estrogen No effect		NoneNo effect	1 study	46 people
Studies that measured estrogen Grape seed extract is an aromatase inhibitor and a suppressor of aromatase expressionCancer Res · PMID 16740737
	Testosterone	Improves (the measure goes up)			46 people

Skin Health

Hyperpigmentation: changes; see studies

Skin Health: outcomes studied for Grape Seed Extract
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Hyperpigmentation	Changes; see studies		1 study	12 people
Studies that measured hyperpigmentation Oral intake of proanthocyanidin-rich extract from grape seeds improves chloasmaPhytother Res · PMID 15597304

Key findings

Blood PressureImproves (the measure goes down)
Blood FlowImproves (the measure goes up)
Food IntakeMetabolic HealthImproves (the measure goes down)

Shop the evidence-backed picks

Third-party tested Grape Seed Extract products, in the forms the graded studies used where we can match them.

Grade B

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Studies cited

11 studies from PubMed

Effects of grape seed extract in Type 2 diabetic subjects at high cardiovascular risk: a double blind randomized placebo controlled trial examining metabolic markers, vascular tone, inflammation, oxidative stress and insulin sensitivityDiabet Med · PMID 19646193
Effect of Grape Seed Extract and Quercetin on Cardiovascular and Endothelial Parameters in High-Risk SubjectsJ Biomed Biotechnol · PMID 15577189
The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trialsJ Am Diet Assoc · PMID 21802563
Effects of grape seed extract consumption on platelet function in postmenopausal womenThromb Res · PMID 17950783
Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokersMetabolism · PMID 14564675
Proanthocyanidin-rich grape seed extract reduces leg swelling in healthy women during prolonged sittingJ Sci Food Agric · PMID 22752876
Effect of grape seed extract on blood pressure in subjects with the metabolic syndromeMetabolism · PMID 19608210
Grape seed extract is an aromatase inhibitor and a suppressor of aromatase expressionCancer Res · PMID 16740737
The effect of grape-seed extract on 24 h energy intake in humansEur J Clin Nutr · PMID 15042136
An evaluation of the antioxidant activity of a standardized grape seed extract, LeucoselectJ Clin Pharm Ther · PMID 9875688
Oral intake of proanthocyanidin-rich extract from grape seeds improves chloasmaPhytother Res · PMID 15597304