[1] It is likely involved in maintaining cellular redox balance and plays a role in microbial resistance to the antibiotic fosfomycin.

It was isolated and identified (as its bacillithiol-S-bimane derivative) in 2009 from Staphylococcus aureus and Deinococcus radiodurans,[1] although it was first detected in 2007, as an unidentified thiol in Bacillus anthracis.

[2] The naturally occurring free thiol form of bacillithiol has since been synthesised and characterised along with its biosynthetic precursors and its symmetrical disulfide.

[3] Bacillithiol appears to participate in the sensing of peroxides by Bacillus,[4] but may also substitute for glutathione, which is the most common intracellular thiol in eukaryotes and some bacteria.

[5] Furthermore, in vitro kinetic studies have established that bacillithiol is a preferred thiol substrate for the antibiotic resistance enzyme FosB.