Grapeseed extract: Interactions. Precautions. Practice Points


Tests in animal models have found grapeseed extract to be extremely.

Adverse Reactions

Studies using doses of 150 mg/day have found it to be well tolerated.

Significant Interactions

Controlled studies are not available, therefore interactions are theoretical and based on evidence of pharmacological activity.


Additive effect theoretically possible — observe patient.


Increased risk of bleeding theoretically possible — caution.


Decreased iron absorption. Tannins can bind to iron, forming insoluble complexes — separate doses by 2 hours.

Contraindications and Precautions

None known.

Pregnancy Use

Safety has not been scientifically established.

Practice Points / Patient Counselling

• Grapeseed extract has considerable antioxidant activity and appears to regenerate alpha-tocopherol radicals to their antioxidant form.

• Grapeseed extract also has anti-inflammatory actions, reduces capillary permeability, enhances dermal wound healing and reduces photo-damage, inhibits platelet aggregation and may enhance rhodopsin regeneration or content in the retina.

• It is popular in Europe as a treatment forvenous insufficiency and capillary fragility, both of which are supported by clinical evidence. It is also used to relieve eye strain, stabilise diabetic retinopathy and connective tissue disorders.

• Preliminary research has identified cardioprotective effects due to a variety of mechanisms. Possible benefits in pancreatitis and multi-organ protection against damage caused by several pharmaceutical drugs. Anticarcinogenic activity has also been reported.

• Most clinical research has been conducted in Europe with a commercial grapeseed product known as Endotelon®.

• Due to concerns with bioavailability, it is recommended that only preparations containing low-molecular-weight proanthocyanidins be used.

Answers to Patients’ Frequently Asked Questions

What will this herb do for me?

There is evidence that grapeseed extract is a useful treatment for venous insufficiency and capillary fragility and has considerable antioxidant activity. It is also used to treat eye strain, diabetic retinopathy, and enhance wound healing when applied locally.

When will it start to work?

It appears to relieve symptoms of venous insufficiency within 10 days and eye strain within 5 weeks.

Are there any safety issues?

Research suggests it is well tolerated and generally safe; however, people taking anticoagulant medicines should refer to their healthcare professional before taking this substance.