Grape Seed Extract: OPC Proanthocyanidin Antioxidants

Table of Contents

1. What Grape Seed Extract Is (OPCs & Proanthocyanidins)
2. Relationship to Pine Bark Extract & Other OPC Sources
3. Antioxidant Mechanism of Action
4. Cardiovascular Health & Blood Pressure
5. Venous Insufficiency, Edema & Circulation
6. Skin, Collagen & Wound Healing
7. Cholesterol Oxidation & Lipid Protection
8. Cognition & Neuroprotection
9. Metabolic & Other Emerging Uses
10. Forms & Standardization (% OPCs)
11. Doses Used in Research
12. Cautions and Contraindications
13. Key Research Papers
14. Connections
15. Featured Videos

What Grape Seed Extract Is (OPCs & Proanthocyanidins)

Grape seed extract is a concentrated polyphenol preparation made by crushing, de-oiling, and solvent-extracting the seeds left over from wine and grape-juice production. The seeds of Vitis vinifera are an agricultural byproduct of enormous volume, which is part of why GSE became a commercially viable supplement: the raw material is abundant and cheap.

The active compounds are proanthocyanidins — also called condensed tannins or, in their shorter-chain form, oligomeric proanthocyanidins (OPCs). These are flavonoid polymers built from individual flavan-3-ol monomers, principally catechin and epicatechin (the same monomers found in green tea and cocoa). When two to roughly seven of these monomers link together, the result is an oligomer (OPC); longer chains are polymeric proanthocyanidins (PPCs), which are less well absorbed.

OPCs are sometimes referred to by older trade and research names that appear in the literature: procyanidins, leucoanthocyanins, and historically "pycnogenols" (lowercase, a generic chemical term coined by Jacques Masquelier — distinct from the trademarked name of one standardized pine-bark product). When you see any of these terms, the underlying chemistry is the same family of catechin/epicatechin-based flavonoids.

Compared with the proanthocyanidins in cocoa, apples, or cranberries, grape seed proanthocyanidins are notable for two features: a high proportion of galloylated units (epicatechin gallate and related esters, which increase antioxidant potency) and a relatively high fraction of low-molecular-weight oligomers that are absorbable from the gut. This combination is why grape seed is one of the preferred raw materials for standardized OPC supplements.

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Relationship to Pine Bark Extract & Other OPC Sources

Grape seed extract and French maritime pine bark extract (from Pinus pinaster) are the two best-known commercial OPC products, and they are frequently discussed together because they share the same core chemistry and were developed by the same researcher.

The French scientist Jacques Masquelier first isolated proanthocyanidins from peanut skins in 1947 (the date given in Weseler and Bast's 2017 review of his grape seed extract), then patented extracts from both pine bark (1951) and grape seeds (1970). The early interest in his preparations was their effect on the permeability of small blood vessels (capillaries). French maritime pine bark extract, as studied, is a specific patented, standardized extract; grape seed extract is a category of products from grape seeds, sold by many manufacturers under their own standardization specs.

Key similarities and differences:

• Shared backbone — both are dominated by catechin/epicatechin-based proanthocyanidins and both concentrate in collagen-rich tissue and the vascular wall.
• Grape seed proanthocyanidins carry galloylated units (epicatechin gallate esters), one of the chemical features that distinguishes them from pine bark OPCs.
• The standardized pine bark extract contains additional phenolic acids (ferulic, caffeic) and taxifolin as characteristic components, and is sold only as a single standardized product, so its clinical-trial dataset is more uniform.
• Cost — grape seed extract is typically far less expensive per milligram of OPCs, which is why it is often used as a lower-cost alternative to the standardized pine bark extract for the same indications (venous insufficiency, blood pressure, skin).

Other meaningful dietary OPC sources include cocoa and dark chocolate, green tea, cranberries, bilberry and other dark berries, apples, and red wine. Grape seed simply delivers them in the most concentrated, standardized supplemental form. Conceptually, GSE sits alongside other polyphenol antioxidants such as quercetin and curcumin as part of the broader flavonoid-antioxidant toolkit.

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Antioxidant Mechanism of Action

OPCs are direct free-radical scavengers. The multiple hydroxyl groups on the catechin/epicatechin rings donate hydrogen atoms and electrons to neutralize reactive oxygen and nitrogen species — superoxide, hydroxyl radical, peroxyl radicals, peroxynitrite, and singlet oxygen. In laboratory and animal experiments reported by Bagchi and colleagues (2000), a grape seed proanthocyanidin extract gave significantly greater protection against free radicals, lipid peroxidation, and DNA damage than vitamins C, E, and beta-carotene.

But raw radical-scavenging is only part of the picture. The clinically relevant mechanisms of GSE include several indirect, tissue-level effects:

• Collagen and elastin binding/protection — OPCs bind avidly to collagen and elastin fibers and inhibit the enzymes (collagenase, elastase, hyaluronidase) that degrade them. This stabilizes connective tissue and the basement membrane of blood vessels, the structural basis of their "vascular sealing" effect.
• Endothelial nitric oxide support — OPCs increase endothelial nitric oxide synthase (eNOS) activity and protect already-formed nitric oxide from oxidative destruction by superoxide, improving vasodilation and blood flow.
• Capillary stabilization — by protecting the capillary basement membrane and reducing capillary permeability and fragility, OPCs reduce fluid leakage into tissue (edema) and small-vessel bleeding.
• LDL protection — OPCs partition into lipoproteins and inhibit the oxidation of LDL particles, an early initiating step in atherosclerosis.
• Anti-inflammatory signaling — OPCs downregulate NF-κB-driven inflammatory gene expression, reducing production of inflammatory cytokines and adhesion molecules.
• Glutathione and endogenous antioxidant support — like many polyphenols, GSE activates the Nrf2 pathway, upregulating the body's own antioxidant enzymes (glutathione peroxidase, catalase, superoxide dismutase).

A frequently cited property is that OPCs help recycle vitamin C and vitamin E, extending their antioxidant lifespan in tissue — the same network-antioxidant behavior described for alpha lipoic acid and CoQ10. This is why OPC supplements are often framed as "force multipliers" for the rest of the antioxidant network rather than standalone agents.

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Cardiovascular Health & Blood Pressure

Blood pressure is the most-studied clinical use of grape seed extract. A 2016 meta-analysis by Zhang and colleagues (Medicine) pooled 16 randomized controlled trials (810 participants) and found that GSE significantly lowered systolic blood pressure (by about 6 mmHg) and diastolic blood pressure (by about 2.8 mmHg), with larger effects in younger and obese subjects and in people with the metabolic syndrome; the authors called for larger, longer trials. A later meta-analysis of 19 trials (Foshati and colleagues, Pharmacological Research, 2022) found significant reductions in diastolic pressure (about 2.2 mmHg) and heart rate (about 1.3 beats per minute), but the reductions in systolic pressure and the change in flow-mediated dilation were not statistically significant. Individual trials include 150 or 300 mg/day for 4 weeks in people with the metabolic syndrome (both systolic and diastolic pressure fell compared with placebo) and 300 mg/day for 6 weeks in a beverage in people with pre-hypertension (systolic pressure fell; pressure returned to baseline after stopping).

The proposed mechanisms align directly with the antioxidant mechanism above: improved endothelial nitric oxide bioavailability, reduced oxidative inactivation of NO by superoxide, and improved arterial flow-mediated dilation. In the pooled trials, however, the change in flow-mediated dilation (a direct measure of endothelial function) was not statistically significant (Foshati 2022), and a 6-week pre-hypertension trial found no change in it.

Beyond blood pressure, GSE has been studied for broader cardiovascular benefits — improved arterial stiffness, reduced platelet aggregation, and reduced markers of vascular inflammation. The effect sizes are modest, and the research positions GSE as a possible supportive adjunct rather than a replacement for guideline-directed therapy in people with established hypertension or cardiovascular disease. Its research sits alongside that of other vascular-supportive antioxidants and of lipid and ApoB markers.

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Venous Insufficiency, Edema & Circulation

Grape seed OPCs have a long history of use in Europe for chronic venous insufficiency (CVI) — the condition behind varicose veins, leg heaviness, aching, nighttime cramps, and ankle swelling caused by poorly functioning vein valves and leaky capillaries. The capillary effects for which Masquelier's extracts were first recognised point to this use, and the mechanism (capillary sealing plus collagen/elastin stabilization of the vein wall) is well matched to the pathology.

The 2020 Cochrane review of phlebotonics (vein-active compounds) found moderate-certainty evidence that the class as a whole slightly reduces lower-leg edema compared with placebo, but it included only one placebo-controlled trial of grape seed extract, so findings for this extract on its own are limited. In a 2024 Korean randomized trial of 303 patients with chronic venous disease, a grape seed extract was non-inferior to a micronized purified flavonoid fraction (a standard venoactive drug) for symptoms and quality of life over 8 weeks, and in a 2026 open-label trial of 176 people with varicose veins, 150 mg twice daily for 12 weeks plus lifestyle changes reduced venous reflux time more than lifestyle changes alone. In a small double-blind crossover study in healthy Japanese women, GSE reduced leg swelling during 6 hours of sitting. The capillary-stabilizing effect is the common thread: by reducing capillary permeability and fragility, OPCs reduce the leakage of fluid and proteins into surrounding tissue.

OPCs are also studied for diabetic retinopathy and for general microcirculatory support, on the same rationale of strengthening fragile small vessels; in a 12-month Korean randomized trial in non-proliferative diabetic retinopathy, 150 mg/day of grape seed proanthocyanidin extract improved hard exudates more than placebo or calcium dobesilate. Both grape seed extract and French maritime pine bark extract appear in the European phytotherapy literature for these microvascular indications, often interchangeably.

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Skin, Collagen & Wound Healing

The collagen and elastin affinity of OPCs is the basis of grape seed extract's reputation as a skin and connective-tissue antioxidant. By binding collagen fibers and inhibiting the enzymes that degrade them (collagenase, elastase, hyaluronidase), OPCs help preserve dermal structural integrity. They also protect against UV-induced oxidative damage in keratinocytes and fibroblasts.

Documented and studied skin effects include:

• Photoprotection — oral and topical grape seed proanthocyanidins reduced UVB-induced oxidative stress and inflammatory signaling in the skin of hairless mice, and topical grape seed extract was reported to raise sun protection factor in human volunteers; it is studied as a complement to sunscreen rather than a substitute for it.
• Wound healing — topical grape seed proanthocyanidins sped wound closure in mice, linked to VEGF-driven angiogenesis, and in a randomized trial of 129 women a 5% grape seed extract ointment improved caesarean-section wound healing scores compared with petrolatum (a 2.5% ointment did not).
• Melasma and hyperpigmentation — a small Japanese open trial (12 women, no placebo group) found oral GSE improved or slightly improved melasma in 10 of 12 women after 6 months, with a lower melanin index.
• Anti-aging cosmetics — GSE is a common ingredient in serums and creams, frequently combined with vitamin C and vitamin E for a network antioxidant effect.

The connective-tissue-stabilizing logic extends beyond skin to joints, gums, and the vascular wall — anywhere collagen integrity matters — though the dedicated clinical evidence outside dermatology and vascular health is thinner.

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Cholesterol Oxidation & Lipid Protection

It is not LDL cholesterol itself but oxidized LDL that initiates atherosclerotic plaque: oxidized LDL is taken up by macrophages to form the foam cells of early lesions and drives endothelial inflammation. Antioxidants that protect LDL from oxidation therefore target an early, mechanistic step in vascular disease.

Grape seed OPCs partition into lipoprotein particles and inhibit their peroxidation. A 2021 meta-analysis of controlled trials (Foshati and colleagues) found that GSE supplementation significantly lowered malondialdehyde (a lipid-peroxidation marker), oxidized LDL, and high-sensitivity C-reactive protein. In an Italian double-blind crossover trial in 24 male heavy smokers, 300 mg/day of a grape procyanidin extract for 4 weeks did not change blood lipids but reduced oxidized-LDL products by about 15% and lengthened the time before LDL began to oxidize. In a 2-month trial in 40 people with high cholesterol, GSE alone did not lower cholesterol, the combination with chromium lowered total and LDL cholesterol, and the fall in antibodies to oxidized LDL in the GSE groups was a trend that did not reach statistical significance.

The effect of GSE on the lipid panel numbers themselves (total cholesterol, LDL-C, triglycerides) is modest and inconsistent across trials; the more reliable and mechanistically interesting finding is reduced LDL oxidation. This positions GSE alongside CoQ10 as a supplement aimed at slowing the oxidative damage that converts circulating LDL into a plaque-forming particle, relevant to anyone tracking ApoB or Lipoprotein(a).

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Cognition & Neuroprotection

Polyphenols that cross the blood-brain barrier can scavenge radicals in neural tissue and support cerebral blood flow, and grape seed OPCs have been studied for cognitive and neuroprotective effects. In a randomized, double-blind, placebo-controlled trial in 111 healthy older adults (Calapai and colleagues, 2017), 250 mg/day of a Vitis vinifera extract for 12 weeks improved Mini-Mental State Examination and RBANS scores, including attention and immediate and delayed memory, compared with placebo.

Preclinical work is more extensive: grape seed extract reduced brain amyloid-beta levels by about a third and amyloid plaques by about half in an Alzheimer's-model mouse, grape seed polyphenols reduced tau pathology in mouse models, and the extracts protects against ischemic and oxidative neuronal injury, and improves memory performance in aged rodents. The mechanisms involve direct antioxidant protection of neurons, improved cerebral microcirculation (the same capillary-supportive effect seen peripherally), and anti-inflammatory signaling in the brain.

Human cognitive evidence remains early and the effect sizes modest, so on current evidence GSE is a plausible supportive agent rather than a proven cognitive therapy. As with cardiovascular use, its strongest rationale is vascular: protecting the brain's small vessels and endothelium. It is studied in the same brain-and-vascular antioxidant context as bilberry and omega-3 fatty acids.

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Metabolic & Other Emerging Uses

Beyond the core cardiovascular, venous, skin, and lipid indications, grape seed extract has a growing list of emerging research applications:

• Glycemic control — in a 4-week double-blind crossover trial in 32 people with type 2 diabetes, 600 mg/day of GSE improved fructosamine (a marker of average blood sugar), glutathione, and hsCRP, but not insulin resistance (HOMA-IR) or endothelial function; a 4-week trial in the metabolic syndrome found no change in blood glucose.
• Edema and post-exercise recovery — in a small trial in 16 young men, 300 mg/day of GSE after eccentric exercise lowered creatine kinase (a muscle-damage marker) at 96 hours but did not change muscle soreness or strength.
• Anti-microbial and oral health — grape seed proanthocyanidins have shown activity against cariogenic bacteria and have been studied as a dentin-collagen cross-linking agent in dentistry.
• Cancer chemoprevention (preclinical) — GSE induces apoptosis and inhibits proliferation in numerous cancer cell-line and animal models. This is laboratory-stage evidence only; GSE is not a cancer treatment, and how antioxidant intake interacts with chemotherapy timing is an unresolved question in oncology.
• Kidney and organ protection — animal models show GSE reduces oxidative and ischemia-reperfusion injury to the kidneys, liver, and heart.

These emerging uses share the same underlying mechanism — broad antioxidant and anti-inflammatory protection plus microvascular support — but most rest on preclinical or small-trial evidence.

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Forms & Standardization (% OPCs)

Because grape seed extract is sold by many manufacturers, standardization is the main way products differ. Products are defined by their proanthocyanidin content:

• Standardized to 95% proanthocyanidins (OPCs) — the most common and best-studied specification. A "95%" product means 95% of the extract by weight is proanthocyanidins.
• Standardized to ~90% or to a stated polyphenol percentage — some labels report total polyphenols rather than OPCs specifically, and the two figures are not equivalent.
• Trademarked research extracts — a few specific, well-characterized standardized grape seed extracts were used in much of the published research, so results from one extract may not transfer to other products.
• Beverage-delivered extracts — some blood-pressure trials gave the extract in a drink rather than a capsule (for example, 300 mg/day in a low-calorie juice in a pre-hypertension trial).
• Low-molecular-weight (LMW) OPC extracts — preferentially concentrate the smaller, more absorbable oligomers (dimers, trimers) over the poorly absorbed polymers.

Labels vary: the trials used extracts with a stated percentage of proanthocyanidins (most often 95%) and a clear milligram amount of extract per capsule, while some products list only "grape seed" with no standardization. Capsules and tablets are the standard delivery form; GSE is water-soluble and its absorption does not depend on dietary fat (in contrast to fat-soluble CoQ10).

A note on absorption: only the smaller oligomers and monomers are meaningfully absorbed intact; the larger polymers are not, though they are metabolized by gut bacteria into smaller phenolic acids that are absorbed and may carry biological activity. This is one reason low-molecular-weight standardized extracts are sometimes preferred.

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Doses Used in Research

• General antioxidant support — 100-200 mg/day of a 95% OPC standardized extract is a commonly cited range
• Blood pressure / cardiovascular — 100-300 mg/day; the blood-pressure trials described above used 150-300 mg/day for 4-16 weeks
• Chronic venous insufficiency & edema — 300 mg/day (150 mg twice daily) for 12 weeks in the 2026 varicose-vein trial
• Skin / photoprotection / anti-aging — the melasma trial used daily oral extract for 6 months; topical preparations are studied separately
• LDL-oxidation protection — 200-300 mg/day in the smoker and high-cholesterol trials
• Cognitive / neuroprotective support (investigational) — 250 mg/day of a grape extract for 12 weeks in the older-adult trial

Notes from the research. Grape seed extract is water-soluble, so its absorption is not tied to a meal. Effects on blood pressure, edema, and oxidative markers typically take 4-12 weeks to become apparent, so response is generally judged over at least that period. There is no established upper limit for general use, but most clinical evidence sits in the 100-300 mg/day range; 600 mg/day was used for 4 weeks in a diabetes trial, and an open-label 4-week safety study in 29 healthy Japanese adults found doses up to 2,500 mg/day generally well tolerated (serum iron fell temporarily in two people at the top dose). GSE is often studied alongside vitamin C and vitamin E (network antioxidant recycling) and is often discussed interchangeably with French maritime pine bark extract for the same indications.

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Cautions and Contraindications

NCCIH describes grape seed extract as generally well tolerated when taken orally or used topically. Important considerations:

• Anticoagulant / antiplatelet interaction — OPCs have mild antiplatelet activity and may add to the effect of warfarin, aspirin, clopidogrel, and the direct oral anticoagulants, theoretically increasing bleeding risk. The research raises a concern for people taking blood thinners, and drug-interaction references commonly list it among supplements stopped before scheduled surgery.
• Blood pressure medications — GSE's mild antihypertensive effect can add to ACE inhibitors, ARBs, calcium channel blockers, beta-blockers, and diuretics, so combining them raises a concern about additive blood-pressure lowering.
• Possible CYP enzyme effects — grape-derived polyphenols may modestly affect drug-metabolizing enzymes (analogous to grapefruit, though weaker); this matters most for narrow-therapeutic-index drugs, and pharmacists track interactions with specific medications.
• GI upset — uncommon; nausea, headache, dry/itchy scalp, dizziness, or abdominal discomfort have been reported.
• Allergy — rare, but the research raises a concern for anyone with a known grape allergy.
• Pregnancy and breastfeeding — there is no good safety data on GSE as a supplement during pregnancy and lactation.
• Cancer chemotherapy — as with other antioxidants, the research raises a concern about adding GSE during active treatment, since some chemotherapy mechanisms depend on oxidative stress.

Decisions about supplements belong with a clinician.

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Key Research Papers

1. Zhang H, Liu S, Li L, et al. The impact of grape seed extract treatment on blood pressure changes: a meta-analysis of 16 randomized controlled trials. Medicine (Baltimore). 2016;95(33):e4247. — doi:10.1097/MD.0000000000004247
2. Foshati S, Nouripour F, Sadeghi E, Amani R. The effect of grape (Vitis vinifera) seed extract supplementation on flow-mediated dilation, blood pressure, and heart rate: a systematic review and meta-analysis of controlled trials with duration- and dose-response analysis. Pharmacological Research. 2022;175:105905. — PubMed PMID: 34798267
3. Schaefer E, Peil H, Ambrosetti L, Petrini O. Oedema protective properties of the red vine leaf extract AS 195 (Folia vitis viniferae) in the treatment of chronic venous insufficiency. A 6-week observational clinical trial. Arzneimittelforschung. 2003;53(4):243-246. — doi:10.1055/s-0031-1297103
4. Sano A, Tokutake S, Seo A. Proanthocyanidin-rich grape seed extract reduces leg swelling in healthy women during prolonged sitting. Journal of the Science of Food and Agriculture. 2013;93(3):457-462. — doi:10.1002/jsfa.5773
5. Sivaprakasapillai B, Edirisinghe I, Randolph J, et al. Effect of grape seed extract on blood pressure in subjects with the metabolic syndrome. Metabolism. 2009;58(12):1743-1746. — doi:10.1016/j.metabol.2009.05.030
6. Vinson JA, Proch J, Bose P. MegaNatural Gold grapeseed extract: in vitro antioxidant and in vivo human supplementation studies. Journal of Medicinal Food. 2001;4(1):17-26. — doi:10.1089/10966200152053677
7. Bagchi D, Bagchi M, Stohs SJ, et al. Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention. Toxicology. 2000;148(2-3):187-197. — doi:10.1016/S0300-483X(00)00210-9
8. Sharma SD, Meeran SM, Katiyar SK. Dietary grape seed proanthocyanidins inhibit UVB-induced oxidative stress and activation of mitogen-activated protein kinases and nuclear factor-κB signaling in in vivo SKH-1 hairless mice. Molecular Cancer Therapeutics. 2007;6(3):995-1005. — doi:10.1158/1535-7163.MCT-06-0661
9. Yamakoshi J, Sano A, Tokutake S, et al. Oral intake of proanthocyanidin-rich extract from grape seeds improves chloasma. Phytotherapy Research. 2004;18(11):895-899. — doi:10.1002/ptr.1537
10. Wang YH, Yang XL, Wang L, et al. Effects of proanthocyanidins from grape seed on treatment of recurrent ulcerative colitis in rats. Canadian Journal of Physiology and Pharmacology. 2010;88(9):888-898. — doi:10.1139/Y10-071
11. Wang YJ, Thomas P, Zhong JH, et al. Consumption of grape seed extract prevents amyloid-β deposition and attenuates inflammation in brain of an Alzheimer's disease mouse. Neurotoxicity Research. 2009;15(1):3-14. — doi:10.1007/s12640-009-9000-x
12. Kar P, Laight D, Rooprai HK, et al. 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 sensitivity. Diabetic Medicine. 2009;26(5):526-531. — doi:10.1111/j.1464-5491.2009.02727.x
13. Vigna GB, Costantini F, Aldini G, et al. Effect of a standardized grape seed extract on low-density lipoprotein susceptibility to oxidation in heavy smokers. Metabolism. 2003;52(10):1250-1257. — PubMed PMID: 14564675
14. Preuss HG, Wallerstedt D, Talpur N, et al. Effects of niacin-bound chromium and grape seed proanthocyanidin extract on the lipid profile of hypercholesterolemic subjects: a pilot study. Journal of Medicine. 2000;31(5-6):227-246. — PubMed PMID: 11508317
15. Foshati S, Rouhani MH, Amani R. The effect of grape seed extract supplementation on oxidative stress and inflammation: a systematic review and meta-analysis of controlled trials. International Journal of Clinical Practice. 2021;75(11):e14469. — PubMed PMID: 34107109
16. Park E, Edirisinghe I, Choy YY, et al. Effects of grape seed extract beverage on blood pressure and metabolic indices in individuals with pre-hypertension: a randomised, double-blinded, two-arm, parallel, placebo-controlled trial. British Journal of Nutrition. 2016;115(2):226-238. — PubMed PMID: 26568249
17. Martinez-Zapata MJ, Vernooij RW, Simancas-Racines D, et al. Phlebotonics for venous insufficiency. Cochrane Database of Systematic Reviews. 2020;11:CD003229. — PubMed PMID: 33141449
18. Kim SM, Joh JH, Jung IM, et al. Vitis vinifera seed extract versus micronized purified flavonoid fraction for patients with chronic venous disease: a randomized noninferiority trial. Annals of Vascular Surgery. 2024;109:177-186. — PubMed PMID: 39009117
19. Bae S, Kim H, Son NH, et al. Vitis vinifera seed extract reduces venous reflux time in patients with varicose veins: VICTORY randomized controlled trial. Journal of Vascular Surgery: Venous and Lymphatic Disorders. 2026;14(1):102355. — PubMed PMID: 41242464
20. Moon SW, Shin YU, Cho H, et al. Effect of grape seed proanthocyanidin extract on hard exudates in patients with non-proliferative diabetic retinopathy. Medicine (Baltimore). 2019;98(21):e15515. — PubMed PMID: 31124931
21. Khanna S, Venojarvi M, Roy S, et al. Dermal wound healing properties of redox-active grape seed proanthocyanidins. Free Radical Biology and Medicine. 2002;33(8):1089-1096. — PubMed PMID: 12374620
22. Izadpanah A, Soorgi S, Geraminejad N, Hosseini M. Effect of grape seed extract ointment on cesarean section wound healing: a double-blind, randomized, controlled clinical trial. Complementary Therapies in Clinical Practice. 2019;35:323-328. — PubMed PMID: 31003677
23. Calapai G, Bonina F, Bonina A, et al. A randomized, double-blinded, clinical trial on effects of a Vitis vinifera extract on cognitive function in healthy older adults. Frontiers in Pharmacology. 2017;8:776. — PubMed PMID: 29163162
24. Wang J, Santa-Maria I, Ho L, et al. Grape derived polyphenols attenuate tau neuropathology in a mouse model of Alzheimer's disease. Journal of Alzheimer's Disease. 2010;22(2):653-661. — PubMed PMID: 20858961
25. Kim J, So WY. Effects of acute grape seed extract supplementation on muscle damage after eccentric exercise: a randomized, controlled clinical trial. Journal of Exercise Science & Fitness. 2019;17(2):77-79. — PubMed PMID: 30992707
26. Sano A. Safety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects. Food and Chemical Toxicology. 2017;108(Pt B):519-523. — PubMed PMID: 27889390
27. Weseler AR, Bast A. Masquelier's grape seed extract: from basic flavonoid research to a well-characterized food supplement with health benefits. Nutrition Journal. 2017;16(1):5. — PubMed PMID: 28103873

PubMed Topic Searches

1. PubMed: Grape seed extract proanthocyanidin antioxidant
2. PubMed: Grape seed extract blood pressure
3. PubMed: Grape seed proanthocyanidin venous insufficiency edema
4. PubMed: Grape seed extract LDL oxidation cholesterol
5. PubMed: Grape seed proanthocyanidin skin collagen UV
6. PubMed: Oligomeric proanthocyanidins (OPC) vascular
7. PubMed: Grape seed extract cognition neuroprotection
8. PubMed: Grape seed extract diabetes metabolic syndrome

External Authoritative Resources

1. NCCIH — Grape Seed Extract
2. MedlinePlus — Grape Seed Extract
3. PubMed — All research on grape seed extract

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Connections

• Rutin
• Hesperidin
• All Antioxidants
• French Maritime Pine Bark (Pine Bark OPCs)
• Quercetin
• Bilberry
• CoQ10
• Alpha Lipoic Acid
• Curcumin
• NAC (Glutathione Precursor)
• Oxidative Stress
• Cardiovascular Disease
• Hypertension
• Vitamin C
• Vitamin E
• Omega-3 Fatty Acids
• Lipid Panel
• Apolipoprotein B
• Lipoprotein(a)

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