White willow bark extract is obtained from the bark of Salix alba (white willow) through aqueous-ethanol extraction. The primary bioactive compound is salicin, a phenolic glycoside that is metabolized in the body to salicylic acid, the pharmacological precursor to aspirin.
The extract also contains flavonoids, tannins, and other salicylates that contribute to its analgesic and anti-inflammatory effects. Unlike synthetic aspirin, willow bark extract provides a slower, sustained release of salicylic acid with reduced gastrointestinal side effects. Commercially, white willow bark extract is used in natural pain relief supplements, anti-inflammatory formulations, sports recovery products, and weight loss supplements.