Horse Chestnut
Research reviewed: Up until 03/2026
Horse Chestnut (Aesculus hippocastanum (Aescin)) is a dietary supplement with 7 published peer-reviewed studies involving 625 participants, researched for Chronic Venous Insufficiency, Leg Oedema, Varicose Veins and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Chronic Venous Insufficiency
ModerateLeg Oedema
ModerateVaricose Veins
ModerateAnti-inflammatory Effects
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Chronic Venous Insufficiency
To evaluate horse chestnut seed extract (HCSE) for chronic venous insufficiency.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate horse chestnut seed extract (HCSE) for chronic venous insufficiency.
Dose
300 mg/day HCSE (50 mg aescin twice daily)
Participants
240 patients with chronic venous insufficiency
Duration
12 weeks
Results
HCSE significantly reduced lower leg volume and oedema compared to placebo. Symptom scores (leg pain, heaviness, itching) improved significantly. HCSE was comparable to compression stockings in reducing leg volume.
How They Measured It
Leg volume (water displacement), calf circumference, symptom scores
To evaluate horse chestnut seed extract for chronic venous insufficiency.
Study Type
Systematic review and meta-analysis
Purpose
To evaluate horse chestnut seed extract for chronic venous insufficiency.
Dose
600 mg/day (100 mg aescin/day)
Participants
Pooled from 17 RCTs (>1,000 patients)
Duration
Various
Results
HCSE significantly reduced leg pain, oedema, itching, and fatigue in patients with CVI. The body of evidence is strong with consistent results across high-quality trials. HCSE is a recommended first-line treatment for CVI.
How They Measured It
Pooled leg oedema, pain, and symptom scores across RCTs
Leg Oedema
To compare HCSE to compression therapy for leg oedema in CVI.
Study Type
Randomised, double-blind, controlled
Purpose
To compare HCSE to compression therapy for leg oedema in CVI.
Dose
50 mg aescin twice daily vs compression stockings
Participants
240 patients with oedema due to CVI
Duration
12 weeks
Results
HCSE and compression stockings produced equivalent reductions in leg volume. HCSE was preferred by patients with poor adherence to stockings, offering a valuable pharmacological alternative.
How They Measured It
Lower leg volume, oedema score, symptom questionnaire
Varicose Veins
To evaluate HCSE on symptoms associated with varicose veins.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate HCSE on symptoms associated with varicose veins.
Dose
600 mg/day HCSE standardised to 100 mg aescin
Participants
74 patients with varicose veins
Duration
8 weeks
Results
HCSE significantly reduced pain, heaviness, and cramping associated with varicose veins. Vein diameter was modestly reduced in the HCSE group. Aescin reduces venous permeability and improves venous tone.
How They Measured It
Pain VAS, heaviness score, vein diameter ultrasound
To characterise aescin's mechanism of action on vascular endothelium permeability.
Study Type
In-vitro study
Purpose
To characterise aescin's mechanism of action on vascular endothelium permeability.
Dose
Varying aescin concentrations
Participants
Human vascular endothelial cells (HUVECs)
Duration
N/A
Results
Aescin reduced endothelial permeability by upregulating tight junction proteins and inhibiting lysosomal enzyme release. This mechanism reduces extravasation of fluid into tissues, explaining the anti-oedema effects.
How They Measured It
Vascular permeability assays, tight junction protein expression, inflammatory mediators
Anti-inflammatory Effects
To examine aescin's anti-inflammatory mechanism in a rodent paw oedema model.
Study Type
Animal study
Purpose
To examine aescin's anti-inflammatory mechanism in a rodent paw oedema model.
Dose
0.5-3 mg/kg aescin
Participants
Sprague-Dawley rats
Duration
Acute
Results
Aescin dose-dependently reduced paw oedema and PGE2 production. NF-κB activation was inhibited, suggesting aescin exerts anti-inflammatory effects via multiple pathways including COX-2 and NF-κB suppression.
How They Measured It
Paw oedema volume, prostaglandin E2, NF-κB activation
To assess HCSE on inflammatory markers in patients with chronic venous insufficiency.
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess HCSE on inflammatory markers in patients with chronic venous insufficiency.
Dose
600 mg/day HCSE
Participants
54 CVI patients
Duration
8 weeks
Results
HCSE significantly reduced serum CRP, IL-6, and ICAM-1 compared to placebo. Leukocyte-endothelium adhesion was also reduced, confirming anti-inflammatory activity in the venous vasculature.
How They Measured It
CRP, IL-6, ICAM-1, leukocyte-endothelium interaction
Frequently Asked Questions
Common questions about Horse Chestnut research
There are currently 7 peer-reviewed studies on Horse Chestnut (Aesculus hippocastanum (Aescin)), involving 625 total participants. Research covers Chronic venous insufficiency, Leg oedema, Varicose veins and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (4 human studies, 1 animal study), and reported outcomes.
Horse Chestnut has been researched for: Chronic venous insufficiency, Leg oedema, Varicose veins, Anti-inflammatory effects. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 4 out of 7 studies are human trials. The remaining 1 is an animal study. Human trials carry more weight in our evidence scoring system.
Similar Supplements
Other supplements researched for similar health goals
