Hair Biology and Hair Loss: A Comprehensive Review of Anatomy, Growth Cycle, Etiologies, and Therapeutic Interventions

NVL Suvarchala Reddy V., K. Lalitha, M. Ganga Raju, G. Tejasree, C. Lakshmi Tejaswini, L. Varalakshmi, B. Sirisha,

doi:10.5281/zenodo.15581707

Review Paper | Open Access
Volume 02 | Issue 06 | Article Id IJSRT/250305100

Hair Biology and Hair Loss: A Comprehensive Review of Anatomy, Growth Cycle, Etiologies, and Therapeutic Interventions
NVL Suvarchala Reddy V.* K. Lalitha M. Ganga Raju G. Tejasree C. Lakshmi Tejaswini L. Varalakshmi B. Sirisha
Department of Pharmacology, Gokaraju Rangaraju College of Pharmacy, Bachupally, Hyderabad

Abstract

Hair is an integral component of human biology and identity, serving essential roles in protection, sensory perception, and personal aesthetics. Structurally, it comprises the hair follicle embedded in the dermis and the keratinized shaft that extends above the skin. Hair growth follows a complex cycle consisting of four phases�anagen (active growth), catagen (transition), telogen (resting), and exogen (shedding). Any disruption in these phases may result in hair disorders, most commonly hair loss. Hair loss, or alopecia, is a widespread concern affecting individuals regardless of age or gender, and can arise from genetic predisposition, hormonal imbalances, nutritional deficiencies, environmental factors, or stress. This review explores the anatomy and physiology of hair while highlighting the mechanisms and contributing factors behind various types of hair loss, including androgenetic alopecia, alopecia areata, telogen effluvium, and traction alopecia. Treatment options encompass both preventive and therapeutic approaches, ranging from dietary and lifestyle modifications to pharmacological interventions. Medications such as minoxidil, finasteride, and dutasteride are commonly used to manage androgenic hair loss, while newer therapies like JAK inhibitors show promise for autoimmune-related conditions. In addition to allopathic medicine, traditional herbal remedies have gained popularity due to their natural bioactive compounds that promote hair health. Ingredients such as Amla, Bhringraj, Hibiscus, Fenugreek, and Onion are known for their antioxidant and anti-inflammatory properties, which support follicular strength and scalp nourishment. Various hair care formulations�serums, oils, foams, sprays, and lotions�are also reviewed for their effectiveness and application suitability. Overall, this paper emphasizes a holistic and personalized approach to hair care, combining scientific understanding with natural and lifestyle-based strategies. Recognizing the multifactorial nature of hair loss is crucial for developing sustainable and effective solutions to improve both hair and scalp health.

Keywords

Probiotic,GUT Flora, Vitamin, GIT track, Microbs

Introduction

Hair is a unique and essential part of the human body, composed primarily of keratin—a fibrous protein also found in nails and skin. It grows from follicles embedded in the dermis and varies significantly in texture, color, and density among individuals. Beyond its protective role, hair contributes to thermoregulation and sensory input, while also serving as a marker of cultural identity, age, and health. The health of hair is influenced by genetic, hormonal, nutritional, and environmental factors. In recent years, increased attention has been given to hair care due to rising concerns over hair loss, damage, and scalp conditions. This paper aims to provide a comprehensive overview of the structure and function of human hair, examine common hair problems, and evaluate current treatments and maintenance strategies. ^[1]

Understanding Hair: A Defining Trait of Mammals

Hair is a filamentous biomaterial that grows from follicles located in the dermis, and is found exclusively in mammals, making it one of the defining characteristics of the mammalian class. The term "hair" typically refers to two distinct parts: (1) the portion beneath the skin, known as the hair follicle or the bulb when extracted which houses stem cells that enable hair regeneration after shedding or injury; and (2) the shaft, the visible, filamentous part that extends above the skin’s surface ^[2].

Anatomy of Hair: Root and Shaft

Human hair is composed of two primary anatomical components: the hair root and the hair shaft. Anatomy of hair is depicted in figure1.The hair root lies beneath the surface of the skin and is the living part of the hair. It is embedded in the hair follicle, a tunnel-like structure that extends into the epidermis and dermis. In contrast, the hair shaft is the visible, non-living part that protrudes above the skin’s surface. It consists of keratinized dead cells and does not engage in any biochemical activity ^[3].