Willow bark has been used for centuries by herbalists and health professionals worldwide. It is rich in a broad spectrum of phenolic glycosides, including the highly valued salicin. Planetary Herbals Willow Aid unites this concentrated willow extract with Chinese corydalis, boswellia extract, guggul and other renowned soothing botanicals. Lifestyle Recommendations: Drink plenty of pure water, exercise regularly, and supplement the diet with unsaturated fatty acids. Other Planetary Herbals products to support comfort and flexibility include: Flex-Ability and Borage Super GLA 300.