Allulose is a sugar found naturally in small amounts in some foods and manufactured for use as a sweetener. It is less sweet than sucrose and behaves differently in browning, moisture retention and crystallization.
A recipe developed for sugar may need more than a simple weight-for-weight replacement. Products sold as allulose can also be blends. Check the formulation and manufacturer's baking guidance; this culinary description does not establish suitability for an individual's dietary or medical needs.
Reference: Further reading.