What Happens During Telogen, the Resting Phase?
What Happens During Telogen?
The Resting Phase
After the active growth of anagen and the quick transition of catagen, the follicle enters a period of complete pause: telogen. It's the most misunderstood phase of the hair cycle; a lot of people assume "rest" means "problem," when it's actually the opposite: a necessary, programmed step.
What happens during telogen?
During telogen, the follicle enters a state of complete biological rest. The old hair, already transformed into a "club hair" during the previous catagen phase, stays anchored in the pore, but no longer grows or develops.
Despite the appearance of inactivity, something important starts happening behind the scenes: toward the end of telogen, a new anagen phase already begins forming underneath the old hair, even before it's released. In other words, the resting of one hair and the start of growth for the next aren't separate events in time; they overlap.
How long does it last, and how many hairs are in this phase?
Telogen lasts about three months on average. At any given moment, between 9% and 15% of scalp hairs are in this phase.
That's useful context for understanding the pace of the hair cycle itself: since telogen alone lasts about three months, any event that pushes a larger number of follicles into this phase at once will only show up as visible shedding much later, typically two to three months after the original event.
Why does telogen matter so much for understanding hair loss?
A range of factors can push the transition from anagen to telogen earlier than expected, including inflammation, hormonal changes, physical or emotional stress, nutritional deficiencies, poor sleep quality, and certain medications. When this happens broadly, a larger number of follicles enter telogen at the same time, which is the mechanism behind what's known as telogen effluvium, something we touched on briefly in earlier articles.
On the flip side, certain factors favor the transition back into anagen, such as increased local blood flow, direct stimulation of the follicle, and the presence of specific growth factors. That helps explain why approaches to hair health tend to focus on improving circulation and the follicle's environment, rather than trying to "force" growth directly.
What This Means for You
If you've been dealing with heavier shedding a couple of months after a stressful event, physical or emotional, telogen is the piece that explains that delay: today's effect can be a reflection of something that happened two or three months ago. It also means that, in most cases, this type of shedding tends to resolve on its own as follicles complete the cycle and return to anagen.
FAQ
How long does the telogen phase last?
About three months on average, though it can vary from person to person.
Can a hair in telogen still be "saved"?
A hair that's already in telogen won't start growing again; it will eventually be released during the next phase (exogen). What matters at that point is the health of the follicle itself, since it's the follicle that will produce the next hair, in the new anagen phase that already starts forming during telogen.
The Doctor Prime Perspective
Telogen is a reminder that rest, in hair just like in many other areas of health, isn't the same as failure. It's a programmed phase with a clear function: preparing the ground for the next growth cycle.
Continue reading: What Is the Exogen Phase? Inside the Natural Shedding Mechanism
Selected References:
NCBI Bookshelf (NIH), StatPearls: Anatomy, Hair
PMC / National Library of Medicine (NIH), Using the Mechanisms of Action Involved in the Pathogenesis of Androgenetic Alopecia to Treat Hair Loss
PMC / National Library of Medicine (NIH), Integrative and Mechanistic Approach to the Hair Growth Cycle and Hair Loss