Grape Seed Extract (GSE) is classified as a proanthocyanidin also known as OPC’s. They are a class of compounds, which belong to the bioflavonoid family. This is the same class of compounds which pycnogenol (pine bark) belongs to. These compounds share similar properties. (In fact, grape seed extract has all the same benefits of pycnogenol). They function mainly as antioxidants, anti-inflammatories and as enhancers of connective tissue and blood vessel strength. These compounds not only are powerful antioxidants but may enhance capillary strength as well. GSE has been used to improve edema (swelling) in individuals with chronic venous insufficiency. No side effects have been reported with this compound. Most of the benefits of grape seed extract have been demonstrated in laboratory animals or in cultured cells. For example, the ingestion of grape seed extract by rabbits fed a high cholesterol diet appeared to have an inhibitory effect on atherosclerosis associated with inhibition of LDL oxidation. GSE selectively killed two human oral cancer cell lines, more efficiently than human oral normal cell lines.

The recommended adult daily dosage is 50 to 100mg, although up to 200mg (in divided doses) is a safe and effective dose. GSE should be taken with meals.

OPCs found in GSE may have some anticoagulant properties when taken in high doses. Individuals on blood-thinner drugs such as Coumadin (warfarin), heparin, Trental (pentoxifylline) and aspirin should take high doses of GSE only under medical supervision, as high doses of OPCs might cause excessive bleeding.

A study suggests that when taking Pycnogenol, more NO is provided in response to neurotransmitters allowing for better expansion of arteries to carry more blood. This process serves to meet the enhanced oxygen demand of the performing muscle and avoid anaerobic metabolism. This was reported by Dr. Yukihito Higashi, lead researcher of the study. "These results also lead me to determine that Pycnogenol will be a useful natural alternative therapy in various diseases in which oxidative stress is involved in the pathogenesis."

The double-blind, randomized, placebo study was held at the Hiroshima University Graduate School of Biomedical Sciences in Japan. Every day for two weeks young healthy men either took 180 mg Pycnogenol or a placebo. To identify Pycnogenol's effect on the release of NO, an inhibitor of the amino acid L-arginine was infused in patients, which restricts the expansion of arteries in response to the neurotransmitter acetylcholine.

After two weeks of supplementation with Pycnogenol, results revealed blood flow increased in response to acetylcholine stimulation by 42 percent. In contrast, the control group receiving the placebo did not show a pronounced blood flow increase in response to neurotransmitter stimulation.

"Acetylcholine stimulates the cells of arteries to produce NO from L-arginine faster," Dr. Higashi said. "In turn, the NO causes the muscle surrounding arteries to relax, which results in an increase of blood vessel diameters. When subjects had taken Pycnogenol the relaxation of arteries was increased by 42 percent as compared to the group taking placebo tablets."

According to Frank Schonlau, Ph.D, director of scientific communications for Horphag Research, worldwide distributors of Pycnogenol, "While more research is warranted, this is an encouraging breakthrough especially to athletes as Pycnogenol seems to allow people to move faster when exercising by satisfying the enhanced muscle oxygen demand and increasing the blood flow to active muscles. When people are performing heavy physical activity, nerves release neurotransmitter acetylcholine to arteries supplying muscles, which makes them expand, a process that requires enhanced production of NO."

A multitude of studies about Pycnogenol and sports nutrition have been conducted. Most recently, a year ago, Pycnogenol was demonstrated to improve blood circulation and support a lasting aerobic muscle activity during any kind of activity and enhance sports endurance by alleviating cramping and muscular pain in athletes. In short, Pycnogenol is effective for enhancing and prolonging muscle performance during sport, supports muscle adaptation to higher work-load and allows for faster physical recovery.