Pharmaceutical-grade heparin is derived from the mucosal tissue of animals that have been slaughtered for meat such as pigs and cattle. Research conducted between 2003 and 2008 eventually led to the synthetic development of low molecular weight heparins in 2011.

Heparin is found across various different animal species including invertebrates that do not have a coagulation system similar to that found in humans.

In addition to the heparin derived from pigs and cattle, pharmaceutical-grade heparin is also extracted from other animals including turkeys, mice, camel, whales, lobsters, freshwater mussels, clams, shrimps, and mangrove crabs.

Heparin is released from the granules present in mast cells. It acts as an anticoagulant agent to prevent blood clots form forming.

Heparin is capable of inducing angiogenesis when its copper salt is formed. Angiogenesis refers to the formation of new blood vessels. Heparin that does not contain copper is non angiogenic. Heparin can also act as an inhibitor of angiogenesis when it is administered alongside corticosteroids. This effect is independent of the anticoagulant activity of heparin.

Test tubes, vacutainers and capillary tubes contain lithium heparin and are marked with green stickers and green tops. These are used for collecting and transporting blood samples for a wide range of tests. Another anticlotting agent is EDTA, but heparin is preferred because it does not affect the levels of most ions, although the ionized calcium level may be depleted if the blood heparin concentration is too high. In cases where blood levels of lithium need to be assessed, royal-blue-topped vacutainers containing sodium heparin are used.