I've taken Grape Seed Extract and Pycnogenol for years, and have read the research from them. I got hemorrhoids from eating Coconut Oil, and they weren't healing well after I backed off the Coconut Oil even though I was taking Grape Seed Extract and Pycnogenol. I tried Horse Chesnut, and it didn't help either. This product along with Vitamin C cleared them up within days, showing me that Citrus Bioflavinoids are the best of the Bioflavinoids category to heal blood vessels. I then use Grape Seed Exract to add elasticity to the collagen as a fine tuning for blood pressure.