From the Guidelines
The telogen phase is a critical resting stage of the hair growth cycle, lasting approximately 2-3 months for scalp hair, during which hair follicles become dormant and growth stops completely. This phase is characterized by the hair shaft detaching from the blood supply at the base of the follicle, with approximately 10-15% of all hairs in telogen at any given time 1. The detached hair remains anchored in the follicle until it's eventually shed during normal activities like washing or brushing, or when pushed out by a new hair in the subsequent anagen (growth) phase. Telogen hairs can be identified by their characteristic white bulb at the root end. Certain conditions like telogen effluvium can disrupt this phase, causing excessive shedding when too many follicles enter telogen simultaneously due to triggers such as stress, illness, hormonal changes, or medications 1. Understanding the telogen phase helps explain normal hair shedding patterns and provides insight into various hair loss conditions.
Some key points to consider about the telogen phase include:
- The duration of the telogen phase can vary depending on the individual and the location of the hair on the body
- The telogen phase is a normal part of the hair growth cycle, but disruptions to this phase can lead to hair loss conditions such as telogen effluvium
- Hair growth after the telogen phase is approximately 1 cm/month, as seen in patients after chemotherapy-induced alopecia 1
- Iron deficiency has been linked to hair loss conditions, including telogen effluvium, although the evidence is not conclusive 1.
In terms of managing hair loss conditions related to the telogen phase, it's essential to address any underlying triggers or disruptions, such as stress, illness, or hormonal changes. Additionally, maintaining good hair care practices, such as gentle washing and brushing, can help minimize shedding and promote healthy hair growth. Overall, understanding the telogen phase is crucial for managing and treating hair loss conditions, and healthcare professionals should prioritize this knowledge when advising patients on hair growth and maintenance.
From the Research
Telogen Phase of Hair Growth
- The telogen phase is a stage of the hair growth cycle characterized by relative proliferative quiescence 2
- During this stage, the hair follicle is in a state of maintenance, retaining the hair fiber with minimal energy expenditure 2
- Telogen is a highly energy-efficient default state of the mammalian coat, whose function centers around maintenance of the hair fiber and prompt responses to its loss 2
- The telogen phase can be divided into two sub-stages: early 'refractory' and late 'competent' telogen, with changing activities reflected in hundreds of dynamically regulated genes in telogen skin 2
- Telogen serves as an interpreter of circadian output in the timing of anagen initiation and is the key stage during which the subsequent organ regeneration (anagen) is actively prepared 2
- This stage is not a period of dormancy, but rather a period of preparation for the next hair growth cycle, with the hair follicle able to launch a new regeneration cycle in response to various stimuli 2