What is the exogen phase of hair growth, also known as the (exogen) shedding phase?

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From the Research

The exogen phase is a distinct stage of the hair growth cycle characterized by the active shedding of hair strands from the follicle, occurring after the telogen phase and involving the breakdown of anchoring points by proteolytic enzymes, as supported by the most recent study 1.

Key Characteristics of the Exogen Phase

  • The exogen phase is a short-lived phase, typically lasting only a few days, during which the old hair is released and expelled from the follicle 2.
  • This phase is distinct from the telogen phase, which is the resting phase of the hair cycle, and is characterized by the preparation for shedding rather than the actual shedding process itself 3.
  • The exogen phase is a normal physiological process that occurs in all individuals, with humans shedding about 50-100 hairs daily, and is not directly related to pathological hair loss conditions like alopecia 1.

Clinical Relevance of the Exogen Phase

  • Understanding the exogen phase is important for explaining why some hair shedding is normal and expected as part of the continuous renewal process of hair follicles 2.
  • The exogen phase is relevant to the diagnosis and treatment of hair loss conditions, as it can help distinguish between normal and pathological hair shedding 1.
  • Further research is needed to fully understand the mechanisms and regulation of the exogen phase, as well as its relationship to other phases of the hair growth cycle 3.

References

Research

Exogen Hairs in Women with and without Hair Loss.

Skin appendage disorders, 2017

Research

Exogen hair characterization in human scalp.

Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 2007

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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