It is a compatible solute which serves as a protective substance by acting as an osmolyte and thus helps organisms survive extreme osmotic stress.

[4] Ectoine is found in high concentrations in halophilic microorganisms and confers resistance towards salt and temperature stress.

Ectoine was first identified in the microorganism Ectothiorhodospira halochloris,[5][6] but has since been found in a wide range of Gram-negative and Gram-positive bacteria.

[13] It stabilizes proteins and other cellular structures and protects the skin from stresses like UV irradiation and dryness.

[7] Due to its protein stabilizing properties, ectoine has been evaluated as a topical treatment for hay fever.