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Red Vine Leaf Extract (Vitis vinifera folium, AS 195)
A standardised flavonoid extract of red grapevine leaves, taken at 360 to 720 mg a day for chronic venous insufficiency. Placebo-controlled trials show it reduces lower-leg volume and circumference, though the most recent trial, in more advanced disease, found only a small effect, about 20 ml over placebo, with leg pain the only symptom to improve.
What the evidence says
Red Vine Leaf Extract doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from medium-quality meta-analyses and randomised trials published 2000–2026 with a typical study size of 71 participants.
Based on 12 studies · 1 meta-analysis · 3 RCTs · 745 total participants
Confidence
Moderate confidenceBy outcome
Moderate 5.4 because two placebo-controlled trials (260 and 248 people) and a 71-person crossover all found less lower-leg swelling in chronic venous insufficiency up to CEAP C4a, but the newer trial, in more advanced disease, found only about 20 ml over placebo with leg pain the only symptom to improve, a 2026 network meta-analysis did not report a significant pain benefit for it, every placebo-controlled trial tested one manufacturer's proprietary extract, with that manufacturer named in one trial abstract and employing the first author of an open-label study, and no review has pooled the efficacy data.
Red vine leaf extract is made from the red autumn leaves of the grapevine (Vitis vinifera). The studied extract, coded AS 195, is standardised to flavonoids, mainly quercetin-3-O-glucuronide and isoquercitrin. It is a different product from grape seed extract, which comes from another part of the plant and is rich in proanthocyanidins instead.
It is used for chronic venous insufficiency, the leg swelling, heaviness, tension and pain that come from poor venous return. In a 260-person placebo-controlled trial, 360 or 720 mg once daily for 12 weeks reduced lower-leg volume by about 76 to 100 g of displaced water versus placebo, with significantly smaller calf circumference and better symptom scores. The authors describe the ankle circumference reductions only as qualitatively similar but less marked, with no significance stated. A later 248-person trial in more advanced disease (CEAP C3 to C4a) found a much smaller reduction, about 20 ml over placebo, and of the symptoms only leg pain improved, by 6.6 mm on a 100 mm scale. A 71-person crossover trial found better skin microcirculation and oxygen supply at the ankle. Open-label studies report symptom relief within weeks, but without a placebo group.
The evidence is moderate. Every placebo-controlled trial tested a single manufacturer's proprietary extract, the 2011 trial abstract names that manufacturer as the extract's source, and the first author of a 2003 open-label study was employed by it, the only systematic review (5 trials) did not pool results, and an Italian expert consensus reached no agreement on using it alone. Tolerability looks good: a 2026 network meta-analysis found fewer adverse events than control, though it did not report a significant pain benefit for it. It eases symptoms and swelling, it does not treat the underlying vein disease, and it is used alongside compression rather than instead of it. Sudden swelling of one leg needs urgent medical assessment, not a supplement.
In cell studies the extract's flavonoids prevented venular endothelium from becoming leaky when exposed to products of activated blood cells, which is how fluid escapes into the tissue and causes oedema.
In a crossover trial in chronic venous insufficiency it increased microvascular blood flow and transcutaneous oxygen pressure at the ankle versus placebo.
In cultured endothelial and red blood cells it increased nitric oxide synthase activation and antioxidant capacity and reduced oxidative stress, a proposed explanation for the microcirculation change.
Not studied, avoid unless advised by a clinician.
Trials covered disease up to CEAP C4a (skin changes without ulcers), not leg ulcers. Use only as an add-on under a clinician's care, not instead of compression or wound care.
Trials enrolled adults only.
Tip: The trials did not specify food timing. If it upsets the stomach, taking it with a meal is a general way to improve tolerability, and stop if it persists
Red Vine Leaf Extract has an evidence score of 5.4/10 — moderate evidence based on 12 indexed studies, including 1 meta-analysis. A standardised flavonoid extract of red grapevine leaves, taken at 360 to 720 mg a day for chronic venous insufficiency. Placebo-controlled trials show it reduces lower-leg volume and circumference, though the most recent trial, in more advanced disease, found only a small effect, about 20 ml over placebo, with leg pain the only symptom to improve. Representative study: PMID 42529868.
The commonly studied dose of Red Vine Leaf Extract is 360 mg standardised red vine leaf extract once daily, up to 720 mg once daily. These are the doses given in the placebo-controlled trials, for 6 to 12 weeks. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
Timing is flexible for Red Vine Leaf Extract — consistent daily use matters more than the time of day. Trials gave the full daily dose once a day.
Red Vine Leaf Extract is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects are uncommon and include gastrointestinal upset. Use caution if any of these apply to you: Pregnancy and breastfeeding (not studied); Allergy to grapes or grape vine.
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Reviewed by Dr. Baher Al Hakim · Last reviewed October 2026 · evidence from 12 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.