In the C-2 position, chitin has an amino group, while chitosan has an N-acetylamino group instead.

Chitin has an α-1,4′-glycosidic linkage, while chitosan has a β-1,6′-glycosidic linkage.

In the C-2 position, chitin has an N-acetylamino group, while chitosan has an N-acetylamino group in the C-3 position instead.

In the C-2 position, chitin has an N-acetylamino group, while chitosan has an amino group instead.