Most at home laser hair removal devices use intense pulse light (IPL) to damage the hair follicle, they usually can take longer to see results and generally don’t have the volume to cover the larger body areas.
What these at home devices do is heat the hair shaft to the point that it singes the follicle, but not so much that the follicle is permanently demolished.
Over a few sessions, you’ll reduce the amount of hair, but probably not as much as a clinical treatment.
With less power also comes less effectiveness, the at home devices don’t work as well as the pro models. The amount of energy that is used in these small devices is far less than the machines used in clinics.
If they are not used properly, these devices can cause permanent pigmentation problems.