White willow (Salix alba) can be considered the nature’s aspirin. Derived from a tree species native to central and southern Europe and cultivated in North America, white willow bark contains salicin, which the body transform into salicylic acid, which has the same effect as aspirin. In fact, aspirin was originally synthesized using white willow bark and it worked without any of the adverse effects.
Due to the tannins in white willow, some people can develop stomach upset from it. Also, because of the chemical similarities to aspirin, you should not take it if you’ve had an allergic reaction to aspirin in the past.
Researchers have shown that when stacked with guarana seed extract (which contains natural caffeine) and Citrus aurantium (another supplement which is available at supermarkets and health food stores), white willowincreases the body’s aptitude to utilize fatty acids while keeping lean muscle tissue.