Hair follows a specific growth cycle with three different phases that occur simultaneously. Humans have approximately 100-150 lashes per eye (upper lid) and lose between two and five from each eye every day.

There are three stages of hair growth:

Anagen (Growth) Phase

The anagen phase is also called the growth stage. During this phase (which lasts between 30 and 45 days), lashes are actively growing. Only about 40 percent of the upper lashes and 15 percent of the lower lashes are in the anagen phase at any one time. Each lash will grow to a specific length and then stop.

Catagen (Transition) Phase

The catagen phase is also known as the transition phase. During this phase, the lash stops growing, and the hair follicle shrinks. If an eyelash falls out or is plucked out during this phase, it won’t grow back right away because the follicle needs to complete the catagen phase before it can move on. This phase lasts between two and three weeks.

Telogen (Resting) Phase

The telogen phase is also referred to as the resting phase. This phase can last more than 100 days before the eyelash falls out and a new one begins to grow. Because each individual lash is in its own phase of the growing cycle, it is normal for a few lashes to fall out most days. It typically takes between four and eight weeks to fully replace an eyelash.