Pantetheine is the cysteamine amide analog of pantothenic acid (vitamin B₅). The dimer of this compound, pantethine is more commonly known, and is considered to be the most potent form of vitamin B₅. Pantetheine is an intermediate in the catabolism of coenzyme A by the body.

Pantetheine is the product of dephosphorylation of phosphopantetheine:

In E. coli, this reaction is catalyzed by for example alkaline phosphatase. The reverse reaction, phosphopantetheine synthesis, is catalyzed by various kinases:

These kinases are able to act upon pantothenoic acid as well and are present in both microorganisms and animal livers.

Pantetheine is degraded by pantetheinase, which splits it into cysteamine and pantothenic acid:

Since pantetheine is a part of coenzyme A, a common cofactor, it is thought to have been present in prebiotic soup. A synthesis mechanism has also been suggested. Pantetheine may also be a component in prebiotic peptidyl-RNA synthesis.