The Human Hair: From Anatomy to Physiology

December 2013 in “ International Journal of Dermatology ”

Barbara Buffoli, Fabio Rinaldi, Mauro Labanca, Elisabetta Sorbellini, Anna Trink, Elena Guanziroli, Rita Rezzani, Luigi Fabrizio Rodella

hair growth cycle anagen catagen telogen exogen follicular stem cells alpha-keratin keratin-associated proteins immune privilege alopecia areata neurohormones scalp hair pubic hair axillary hair phalangeal hair

Studysummary This review summarizes the anatomical and physiological aspects of human hair and its clinical significance, but does not report new research findings.

Our plain-language summary. Not medical advice or a treatment recommendation. Consult a qualified healthcare professional before changing treatment. Full disclaimer

The 2013 document is a review that provides an extensive summary of human hair's anatomy, physiology, and clinical significance. It explains the hair growth cycle, which consists of anagen, catagen, telogen, and exogen phases, and the role of follicular stem cells and cell interactions in this process. The review discusses the molecular structure of hair, particularly the importance of alpha-keratin and keratin-associated proteins, and the concept of immune privilege in hair follicles, which is relevant to disorders like alopecia areata. Hair is classified based on various characteristics, including its response to hormones. The review also examines the growth patterns, structure, and clinical implications of different types of hair, such as scalp, pubic, axillary, and phalangeal hair. It notes the influence of neurohormones on hair growth and pathology, the effects of aging on hair, and the diagnostic uses of hair for testing substances like drugs or metals. The document underscores the importance of hair research in multiple scientific and medical disciplines.

View this study on onlinelibrary.wiley.com →

Discuss this study in the Community →

Research cited in this study

33 / 33 results

research Variations of Scalp, Pubic, and Axillary Hair

8 citations , October 2011 in “Anthropologischer Anzeiger”

This study found significant differences in hair traits among scalp, axillary, and pubic hair in Bengalee Hindu caste females, suggesting these variations could aid in forensic personal identification.

research Human Hair Follicle: Reservoir Function and Selective Targeting

97 citations , September 2011 in “British Journal of Dermatology”

The human hair follicle can store topical compounds and be targeted for drug delivery with minimal side effects.

research Can the Hair Follicle Become a Model for Studying Selected Aspects of Human Ocular Immune Privilege?

21 citations , June 2011 in “Investigative Ophthalmology & Visual Science”

This article argues that human scalp hair follicles could serve as a surrogate model for studying immune privilege in the human eye, offering a novel approach for ocular IP research.

research Melanocyte Stem Cells: A Melanocyte Reservoir in Hair Follicles for Hair and Skin Pigmentation

240 citations , April 2011 in “Pigment Cell & Melanoma Research”

This review discusses the identification and characteristics of melanocyte stem cells, emphasizing their role in hair pigmentation, greying, and skin repigmentation, but reports no new research findings.

research A Neuroendocrinological Perspective on Human Hair Follicle Pigmentation

56 citations , November 2010 in “Pigment Cell & Melanoma Research”

This article discusses the role of neurohormones and neuropeptides in hair follicle pigmentation and outlines promising neuroendocrinological strategies to address greying and damage, but reports no new clinical results.

research The Pathogenesis of Primary Cicatricial Alopecias

150 citations , October 2010 in “The American Journal of Pathology”

This review discusses the pathogenesis and challenges in treating primary cicatricial alopecia, highlighting the need to understand immune protection collapse in hair follicle stem cells; it reports no new clinical results.

research Human Hair Melanins: What We Have Learned and Have Not Learned from Mouse Coat Color Pigmentation

140 citations , August 2010 in “Pigment Cell & Melanoma Research”

This article discusses mouse genetic studies to explore factors influencing melanogenesis, highlighting pH and cysteine's roles, and proposes a hypothesis for human hair color diversity; it reports no new results.

research Investigation of Aging Effects in Human Hair Using Atomic Force Microscopy

20 citations , July 2010 in “Skin Research and Technology”

This study found that aging in Korean individuals is associated with changes in hair diameter and surface structure, as observed through atomic force microscopy.

research Targeting to the Hair Follicles: Current Status and Potential

142 citations , January 2010 in “Journal of dermatological science”

This review covers follicle-targeting drug delivery systems, exploring their potential for improving localized and systemic therapies, and highlights the need for further research into follicle penetration mechanisms.

research Loose Anagen Hair Syndrome

40 citations , January 2010 in “International Journal of Trichology”

This review discusses the diagnostic criteria and guidelines for managing loose anagen syndrome and differentiating it from non-scarring alopecias, but it reports no new clinical results.

research Does Collapse of Immune Privilege in the Hair-Follicle Bulge Play a Role in the Pathogenesis of Primary Cicatricial Alopecia?

39 citations , November 2009 in “Clinical and Experimental Dermatology”

This study reports that in primary cicatricial alopecias, increased expression of certain immune markers in the hair-follicle bulge suggests a collapse of immune privilege, which may contribute to follicle destruction.

research Methods in Hair Research: How to Objectively Distinguish Between Anagen and Catagen in Human Hair Follicle Organ Culture

132 citations , September 2009 in “Experimental Dermatology”

This study introduced a new classification system for distinguishing between anagen VI and early catagen stages in human hair follicle organ culture, using it to confirm eflornithine's ability to induce premature catagen.

research The Biology of Hair Growth

10 citations , January 2009 in “Elsevier eBooks”

This review discusses the structure, functions, and growth cycle of human hair, emphasizing its reduced growth and protective roles, and reports no new research findings.

research Molecular Evolution of the Keratin Associated Protein Gene Family in Mammals: Role in the Evolution of Mammalian Hair

119 citations , August 2008 in “BMC Evolutionary Biology”

This study found that while the KRTAP gene family is unique to mammals, humans have a similar number of these hair gene types as other primates despite having less body hair.

research Neuroendocrinology of Epithelial Hair Follicle Stem Cells

42 citations , March 2008 in “Molecular and Cellular Endocrinology”

This review explores the potential (neuro-)endocrine influences on hair follicle epithelial stem cell biology and emphasizes the need for more systematic research, but it provides no new empirical results.

research Hair Follicle-Specific Keratins And Their Diseases

138 citations , March 2007 in “Experimental cell research”

This review discusses hair keratins and hair follicle-specific epithelial keratins and their association with inherited hair disorders, reporting no new clinical results.

research Shape Variability and Classification of Human Hair: A Worldwide Approach

95 citations , January 2007 in “Human biology”

This study proposes a new, objective method to classify human hair into eight categories based on specific shape measurements, rather than traditional ethnicity-based classifications.

research Human Hair Keratin-Associated Proteins: Sequence Regularities and Structural Implications

52 citations , May 2006 in “Journal of Structural Biology”

This study identified two key pentapeptide quasi-repeats in human keratin-associated proteins, which are similar to motifs found in sheep wool.

research Biology of the Hair Follicle: The Basics

224 citations , March 2006 in “Seminars in Cutaneous Medicine and Surgery”

This article discusses the hair follicle's regenerative cycles and the molecular mechanisms influencing them, emphasizing the need for therapeutic targeting of the "hair cycle clock" to manage hair growth disorders, without reporting new research findings.

research Human Hair Keratin-Associated Proteins

226 citations , January 2006 in “International review of cytology”

Keratin-associated proteins are crucial for hair strength and structure.

research Corticotropin-Releasing Hormone and the Skin

137 citations , January 2006 in “Frontiers in bioscience”

This review discusses the role of corticotropin-releasing hormone in human skin, focusing on its regulation, receptors, and functions, and highlights parallels with the hypothalamo-pituitary-adrenal axis; it reports no new research findings.

research Human KAP Genes: Only Half of It? Extensive Size Polymorphisms in Hair Keratin-Associated Protein Genes

53 citations , June 2005 in “The journal of investigative dermatology/Journal of investigative dermatology”

This article reviews extensive genetic polymorphisms in the keratin-associated proteins of human hair, indicating complexity but reporting no new clinical results and calls for further research on their potential impact on hair structure.

research Multiscale Modelling of Human Hair

49 citations , June 2004 in “Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences”

This study developed a multiscale model to understand human hair fiber mechanics and found that the yield stress decreases linearly with temperature, supported by both simulations and experimental stretching of hair fibers.

research Hair Follicle Differentiation And Regulation

199 citations , January 2004 in “The International Journal of Developmental Biology”

This review discusses advances in understanding hair and hair follicle structure, gene expression, and molecular signals in hair formation, without reporting new clinical findings.

research Variations of Hair Follicle Size and Distribution in Different Body Sites

405 citations , January 2004 in “Journal of Investigative Dermatology”

This study found that hair follicle characteristics vary significantly across different body sites, with the forehead and calf showing the highest potential follicular reservoirs, challenging previous assumptions about skin appendage distribution.

research Human Hair: A Unique Physicochemical Composite

203 citations , June 2003 in “Journal of the American Academy of Dermatology”

This article reviews the structure and chemistry of hair across ethnicities and how these factors affect hair properties and treatment responses, but reports no new research findings.

research Stress And The Hair Follicle

61 citations , March 2003 in “American Journal Of Pathology”

Stress can cause hair loss and skin issues by affecting hair growth cycles.

research Morphogenesis and Renewal of Hair Follicles from Adult Multipotent Stem Cells

949 citations , January 2001 in “Cell”

This study demonstrated that multipotent stem cells in adult mice whisker follicles migrate to produce whisker growth, and that this process requires precise control of stem cell trafficking.

research The Skin POMC System (SPS): Leads and Lessons from the Hair Follicle

66 citations , October 1999 in “Annals of the New York Academy of Sciences”

This article discusses the potential role of a local skin POMC system in the murine hair cycle and cutaneous stress responses, with no new results presented.

research Principles of Hair Cycle Control

109 citations , December 1998 in “The Journal of Dermatology”

This review discusses the hair follicle cycle's complex regulation and highlights the potential for targeting catagen control in future therapies without presenting new experimental data.

research Growth Factors in Hair Organ Development and the Hair Growth Cycle

90 citations , October 1996 in “Dermatologic Clinics”

This study found that red ginseng oil may enhance hair growth and protect skin from UV damage in mouse models by promoting regenerative processes and reducing inflammation.

research Personality Disorders and Psychopathologic Symptoms in Patients With Androgenetic Alopecia

43 citations , July 1994 in “Archives of Dermatology”

This study found that the prevalence of personality disorders in individuals with androgenetic alopecia was significantly higher than in the general population, irrespective of gender.

research Electron Microscope Observations on the Glassy Layer of the Hair Follicle

24 citations , December 1957 in “Experimental Cell Research”

This study observed that the glassy layer of hair follicles in guinea pigs consists of thick collagen-type fibrils organized into two distinct arrays, whereas in young mice, the fibrils are thinner and develop between the outer root sheath and fibroblasts.