Hair growth has four phases. In one hair follicle, Dogs have on average 5 to 22 hairs that are in a constant cycle of growth. New hairs grow, mature hairs rest and old hairs come loose and shed.

Anagen Phase: When hair follicles begin to grow new hair.

Catagen Phase: When hair transitions and stops growing the outer root sheath attaches to the hair.

Telogen Phase: When the hair rests and is at a standstill, at this stage it does not grow or shed.

Exogen Phase: Where the hair falls out ready for a new hair to grow.