1. INTRODUCTION:

Cosmetic is derived from the Greek word “adorn,” or to add something aesthetically pleasing to someone or something. It can be described as a substance that comes into contact with the skin, hair, nails, lips, teeth, and mucous membranes, among other body parts¹. Hair is important part of human body and it influence the overall appearance of person². One essential element of mammalian skin is the Hair Follicle (HF). While specialized nasal hairs, eyebrows, and eyelashes have some protective effects against the environment, thick scalp hair provides protection against actinic damage.

As a functionally unique mechanosensory organ, HF contributes to sensory perception by providing the broad tactile sensation range of the covered skin surface. Hair performs thermoregulation, physical protection, tissue restoration and regeneration, and psychosocial functions The medical therm of hair loss is alopeciaIt can be temporary or permanent^3,4

2. HAIR AS A COMPOSITE MOLECULAR SYSTEM:

2.1 Structure and Function:

Among its many functions are protection and thermoregulation. Hair controls body temperature in mammals, including nonhuman primates, by retaining heat or warding off cold. Hair can serve as a disguise and a sexual lure. Human hair serves as a sensory organ and aids in sweat thermoregulation. Humans also have specialized hair, such brow and eyelash hair. Because hair affects a person’s identity and self-perception, it plays a significant role in human psychology. Alopecia and other hair loss disorders are the conditions where the psychological role of hair is most apparent.

2.2 Anatomy of Human Hair:

Hair follicles located in the fatty layer of the scalp are where hair grows. Hair follicles actually grow in groups of one to four hairs called “follicular units,” which is the opposite of the common misconception that hair grows in single strands. A hair bulb, which houses the growth mechanism for hair production, is located at the base of each hair follicle. The blood arteries in the dermis provide sustenance for the hair follicles. The hair shaft is created by the division and development of cells. The hair retains its delicate structure while it is still growing beneath the epidermis. Its outer layer hardens into keratin once it pushes past the epidermis.⁵

Cortex:

Hair is primarily composed of fibrous α-keratin proteins, which are organized within three main components: the protective cuticle sheath, the fibrous cortex, and the medulla.

Cuticle:

Composition: The cuticle, derived from a single cell layer in the follicle, contains β-keratins and features a layered, scale-like structure with edges facing outward. It includes several sub-layers:

Epicuticle: A thin membrane that covers the scales, enhancing protection.

Exocuticle: Rich in cysteine, giving it strength and rigidity due to the sulfur bonds.

Endocuticle: Situated between the cuticle and cortex, it has low sulfur content, which leads it to swell in water and affects hair texture.

Cortex:

Structure: The primary structural element of hair is the cortex, which is made up of cortical cells arranged in macrofibrils with intermediate filaments. Make-up: composed of two keratin protein types, neutral-basic (type II) and acidic (type I), which can form stable structures ranging from dimers to tetramers to an IF. The Ifs are encircled by matrix proteins that are rich in cysteine, glycine, and tyrosine. These proteins form robust disulfide connections, which increase the mechanical strength of the hair.

Pigmentation:

Melanin: Melanin particles dispersed throughout the cortex determine hair color, with variation in pigment quantity and distribution affecting the shade.

1. Color and Melanin: Hair color is influenced by both the type and quantity of melanin present, as well as the arrangement of pigment granules in the hair cortex.

2. Medulla and Structure: Coarser hair may contain vacuolated cells in the medulla, the innermost part of the hair, which constitutes an empty space and contributes minimally to the hair’s mechanical strength.

3. Keratin and Molecular Bonds: Hair consists mostly of keratin, a protein with long molecular chains held by various interactions, from strong covalent bonds to weaker hydrogen bonds and hydrophobic interactions. Reactivity of hair depends on the availability of these reactive groups, which is influenced by fiber structure.

4. Ethnic Hair Types: Human hair is typically classified into three main ethnic categories (Asian, Caucasian, and African), though the amino acid composition of hair keratin is largely consistent across these groups.

The passage highlights both structural and biochemical characteristics, emphasizing how these elements contribute to the physical properties and diversity of hair.

Figure 1: Transverse Section of a Hair Follicle. This transverse hair follicle section shows the hyaline layer, hair cortex and medulla, Huxley and Henle layers, and outer or dermic coat. Henry Vandyke Carter, Public Domain, via Wikimedia Commons

3. HAIR GROWTH CYCLE:

The human hair growth cycle is further divided into the growth phase (anagen I-VI), regression phase (catagen) and resting phase (telogen) [Hair loss is the separate active process which is called as exogen]., whereas HF remained empty during stage. Among the matrix keratinocytes that create the inner root sheath and hair fiber, phase angen exhibits a higher metabolic activity.

It is further divided into six sub phases, one of which is called pro-anagen, and includes phases I–V.The met-anagen phase follows, which leads to hair growth on the Epidermal surface. The follicle at the end of the anagen is firmly fixed in the subcutaneous tissue and rests deep, whereas the bulb shifts position by migrating more superficially, beneath the arrectorpilati muscle insertion. Apoptosis, final differentiation, and HF involution mark the end of the anagen period. The catagen phase, which lasts two to five weeks, is a brief conventional phase of the cycle that falls between the anagen and telogen phases and molecular changes associated with apoptosis. The initial cessation of bulb melanin formation is an indication of involution. The matrix Keratinocytes stop proliferating and go through terminal differentiation, while melanocytes stop making melanin and absorb dendrites. Stem cells that are lateral to the dermal papilla during the catagen phase are immune to apoptosis and permit reproduction during the early anagen phase. The follicle moves into the telogen phase, which is defined as the relative rest in terms of activity and proliferation, after regression. Three to four months make up the telogenperiod.The hair is not as securely. The connection between the lower portion of hair and the follicular During telogen, sac disappearance activity differs greatly from inaction. Although the precise nature of the process is yet unknown, the structure of the hair root suggests that this exogenous process involves proteolytic processes among cells at the base of telogen hair.Kenogen happens between the appearance of new anagen hair and the hair follicle staying empty following telogen hair loss. The decline in normal hair cycles and the rise in kenogen hairs in conjunction with Vellus hair are the main signs of AGA worsening.⁴

4. Types of hairfall and their treatments:

4.1 Androgenetic alopecia:

Alopecia may be caused by a variety of causes, including hormone imbalance, autoimmune illnesses, genetics, and environmental factors.⁶

Androgenetic alopecia (AGA) is indeed the most prevalent form of hair loss, significantly impacting both men and women. It has a clear genetic component, and histological studies reveal characteristic changes in hair follicle structure, especially in genetically susceptible scalp regions.

Specifically:

1. Histological Characteristics: In affected areas, terminal hair follicles shrink (known as follicular miniaturization), the growth (anagen) phase of the hair shortens, and hair shaft thickness decreases. This miniaturization results in finer, shorter hairs over time⁷.

2. Patterns of Hair Loss:

Men: Typically exhibit receding hairlines at the temples and thinning at the crown (back of the head), commonly categorized as the Norwood–Hamilton pattern.

Women: Experience more diffuse thinning at the scalp’s midline, often referred to as the Ludwig pattern.

3. Underlying Mechanism: Androgenetic alopecia, particularly in men, is linked to genetic variations in the androgen receptor^7,8. A critical factor in this process is dihydrotestosterone (DHT), which is converted from testosterone via the enzyme 5α-reductase. DHT binds to androgen receptors in hair follicles, triggering the miniaturization process. Notably,⁹ AGA is not directly correlated with androgen levels in the bloodstream; instead, it is the sensitivity of hair follicles to DHT that drives the condition.

4. Androgenetic alopecia (AGA) is influenced by genetic factors, with a variability in how sensitive hair follicles are to normal levels of circulating androgens. This variability is often attributed to multiple genes, with the androgen receptor gene located on the X chromosome. This means that in men, the susceptibility to AGA can be inherited maternally¹⁰.

For women, research is more limited, but genetic predisposition is also evident¹¹. Women’s cases may sometimes involve more complex hormonal interactions, especially if signs of hormonal imbalances, such as acne or hirsutism (excessive hair growth), are present.

Women experience hair loss nearly more commonly than men do, making it a problem that is typically disregarded and undervalued.

Treatment:

The European guideline for diagnosing and treating androgenetic alopecia emphasizes halting hair loss and, if possible, reversing follicle shrinkage to encourage hair regrowth¹². Treatment success is ideally documented through standardized photos and, if available, a phototrichogram.

Currently, two medications are recognized as effective for androgenetic alopecia:

1. Topical minoxidil solution – suitable for both women and men.

2. Finasteride tablets (1 mg) – recommended only for men.

These therapies aim to address the underlying causes of hair loss and promote healthy hair regrowth where possible.

Topical treatment with minoxidil:

The rate of DNA synthesis in anagen bulbs increased, indicating that minoxidil accelerated the transition to the anagen phase by stimulating telogenfollicles secondary hair germ cells.¹³

Minoxidil, a calcium channel opener, is an established topical treatment for androgenetic alopecia. It’s available in a 2% solution for women^14,15and a 5% solution or foam for men¹⁶, which can typically be purchased over-the-counter. Although primarily approved as a once-daily treatment for men, the 5% foam may soon be approved for once-daily use by women, simplifying treatment routines.

This solution is the only topical medication for androgenetic alopecia backed by high-level (level 1) evidence, showing effectiveness in large-scale studies.

Results include:

Stopping hair loss in 80–90% of those treated.

Thicker hair observed in around 50% of cases^14,16

Reported side effects include scalp redness, scaling, occasional contact dermatitis, and in some women, hypertrichosis (excess hair growth) around the temples.

Systemic treatment with finasteride:

Finasteride, a type II 5α-reductase inhibitor, is approved for men aged 18–41 in Germany for the treatment of androgenetic alopecia at a dose of 1 mg taken once daily⁹. Like minoxidil, finasteride is backed by level 1 evidence and has shown success in clinical studies, with results including: Stopping hair loss in 80–90% of users.Thickening of hair observed in about 50% of users.Finasteride is generally well tolerated but has some mild side effects, including a reversible loss of libido, erectile dysfunction (about 2% incidence), and a slightly higher incidence of gynecomastia (breast tissue enlargement in men). Despite concerns on some online platforms about a potential link to prostate cancer, breast cancer, or infertility, these claims lack scientific backing.

Important considerations:

Finasteride is not approved for women, as it can cause genital defects in male fetuses and has shown to be ineffective in postmenopausal women. Dutasteride, a dual 5α-reductase inhibitor, is approved only for benign prostatic hyperplasia and is not recommended off-label for alopecia treatment⁹.

4.2 Alopecia areata:

Alopecia areata is a condition characterized by sudden, often round, patches of hair loss on the scalp, which can sometimes spread in a centrifugal or multilocular pattern. This autoimmune condition has a genetic component and is associated with other autoimmune diseases like atopic eczema, Hashimoto’s thyroiditis, Graves’ disease, and vitiligo.

Here’s a summary of key aspects:

Forms:

Alopecia areatatotalis affects the entire scalp.

Alopecia areatauniversalis affects the entire body.

Symptoms:

Initial symptoms often include a marked and diffuse hair loss. Around 1-2% of people experience this in their lifetime, making it the third most common type of hair loss after androgenetic and diffuse alopecia¹⁷.

Treatment:

Treatment options for alopecia areata vary based on the severity of the condition and patient needs. Here’s an overview:

Mild Cases: Observation: Waiting for spontaneous remission may be appropriate if the hair loss is mild and not distressing. Zinc Supplementation: Zinc, as an immune modulator, is generally side-effect-free and can be used in children, although its effectiveness is not definitively proven¹⁸.

1. Topical Corticosteroids: These can be applied for several weeks with minimal risk, although their efficacy is not fully established. However, a high-dose steroid foam has shown benefits in certain cases when tested against a control side of the head^19,20.

2. Intralesional Corticosteroid Injections: nTriamcinolone crystals may be injected directly into affected areas if the patient has only a few stable patches. This method is often preferred for localized, stable lesions²¹

Systemic Corticosteroids: Rarely, oral corticosteroids may be used but are generally reserved for more severe cases.

Hair related issues: Split ends, dry hair, and dandruff greasy hair, hair that is frizzy, hairs on the legs, Heat damage, color damage, and hair loss grey hair.²²

5. TYPES OF HAIRS:

One of the four curl patterns that Andre Walker, Oprah Winfrey's stylist for decades, is credited with creating, is a system for classifying hair. When you were researching your hair type, you might have read of it before.

Type 1	Straight hair
Type 2	Wavy hair
Type 3	Curly hair
Type 4	Coily hair

Figure 3: Types of hair

Based on how tight or unfastened the coils and curls are, these types are similarly separated into subcategories; this offers every range an A, B, or C. knowing what each type requires is crucial for maintaining its health and style.

Type 1: Straight:

Type 1 hair not having any natural ringlets. whether or not or not they are thick or thin, atrocious or coarse, the man or woman beaches fall from root to tip without swaying. on the grounds that this sort of hair is susceptible to grow to be oily, many stylists recommend reading the label to make certain the product you're buying won't make your hair oilier. Dry shampoo is a wonderful desire for oldsters with immediately, oily hair due to the fact frequent washing might likely cause your scalp to create too much oil. additionally, dry washes are counseled for this hair kind.

Type 2: Wavy hair

Type 2A

Type 2 hair has certainly a smooth, tousled texture hair has a tendency to be without delay from the scalp to near eye degree. Furthermore, you've got a sloppy, ill-defined wave from the extent of the eyes to the ends. Avoid the operation of products that are delicate or oil painting- primarily grounded to avoid leveling out that surge. rather, define your swells with a gel or upload a light scum to the bottom.

Type 2B

Type 2B hair curls from its center to the ends, just like kind 2A. The S form of the ringlets is more distinct. Straightening it is able to take a bit extra work, but applying salt spray makes it simple to gain that beachy fashion. The balayage style, in which hairdressers hand-paint pigment on the out of doors layer of hair, is most applicable for kind 2B.

Type 2C

The most nicely-described S-shaped waves are type 2C. This type of hairs are regularly thick and they will be at risk of frizz in awful weather. Lovelace Cosmetics logo recommends to use a diffuser, which is a toothy tool that snaps onto the end of your blow dryer, to eliminate the frizz. Anti humidity products are encouraged proper right here.²³

Type 3: Curly

Type 3A

Type 3A hair are having loose loops made from S-formed curls. The curls' circle is pretty larger than a taper candle's huge stop. essential styling advice: cleaning with this shape of hair can reason frizz and damage curl definition. After your curls are dried, resist brushing them to save you poofy hair. grasp stylist Silvana Castillo, who based The Curl Whisperer, an Miami salon that makes a speciality of hair sorts along with three and 4, shows products and techniques that accentuate herbal curls. What would possibly she advocate exceptional? Drop the ponytail. Hair health might also moreover go through if hair is pulled again into buns or ponytails, despite the fact that this may be required for certain activities like walking out or assembly paintings-related obligations. at the same time as performed regularly, this technique may additionally result in thinning and lack of hair across the hairline, similarly to a discount of curl definition, Castillo said.the load for the ponytail places non-prevent stress at the hairline, inflicting this example, often called traction alopecia, to boom.

Type 3B

The circumference of kind 3B curls is throughout the identical width as a Sharpie marker's barrel. Curls have too much the extent and grow from the roots. those ringlets are usually require moisture to maintain their form unique spiral. But, live away from sulfates and silicone on your curl products. Over time, they may dry up your hair and result in breakage, regardless of the reality that they may in short lessen frizz.

Type 3C

3B curls have a circumference that is approximately the equal diameter because the barrel of a Sharpie marker. Curls broaden through the roots and have an excessive amount of volume. Typically, those ringlets need moisture to keep their feature spiral form. but, keep away from the usage of silicone and sulfates in your curl arrangements. Whilst they may briefly reduce frizz, they will purpose your hair to dry out and break over time. instead of blow-drying your hair, the yank Academy of Dermatology advises letting it air dry.²⁴

Type 4: Coils:

Type 4A:

An S-fashioned coil which you may wrap round a timber stick is the curl shape for 4A hair. in step with Castillo, "type 4 hairs is the more touchy." It requires several wetness and you need to be extraordinarily type with it. but wetness does now not usually require the usage of oils. Deep conditioning masques, butters, and creams are all first rate options for maintaining your hair healthful. Castillo claims that at the same time as a few stylists recommend for designs that will let you tuck away touchy ends to shield them as they develop out, these appears frequently reason more damage than gain. The hair is out of imaginative and prescient, however conditioning remedies can not reap it both. "The coil development absolutely disappears after weeks of wearing your hair in a preventative style”. even as you eliminate the braids, the cuticle will become like tiny fish hooks that latch on to each other and smash as it remains dry and open," Castillo described. put on it loosely simply so it stays moistened alternatively.

Type 4B:

4B hair has zigzag curls. Shingles are a not unusual method for highlighting and shaping your curls. moist hair is first step within the shingling. After the use of a variety of go away-in conditioning to hydrate and situation your hair, lightly untangle it collectively along with your fingertips and divide it into four portions. Twist the curls around collectively with your index finger after which work curl cream or gel at some stage in the complete duration of each curl.

Type 4C

Type 4C coils are the tightest & maximum sensitive. if you comb too often or aggressively, you hazard breaking them, therefore it is essential to regularly use wealthy conditioners to nourish your hair. Shea butter lotions and coconut oils stay famous. Co-washing, which involves rinsing your hair using moisturizing conditioner as opposed to shampoo, is becoming extra well-known. How approximately in phrases of styling? The natural texture of 4C hair is being embraced via many human beings.²⁵

6. CHEMICAL HAIR TREATMENTS:

Hair Straightening: This involves breaking and re-forming disulfide bonds in the hair's keratin structure using reductive agents (like thioglycolic acid) or alkaline agents (like sodium hydroxide). While effective for achieving straight hair, these processes can compromise hair integrity, leading to damage and decreased strength.

Hair Waving: Similar to straightening, this involves breaking disulfide bonds and then re-oxidizing them to form curls. It also utilizes ammonium salts as reducing agents and requires careful neutralization to stabilize the new shape.²⁶

7. HEALTH HAZARDS:

Both shampooing and chemical treatments can inadvertently damage hair. Shampoos might lead to dryness and scalp issues due to harsh ingredients, while chemical treatments can weaken hair fibers, making them prone to breakage and loss of moisture. The use of harsh chemicals like formaldehyde in some treatments raises safety concerns²⁶

Chemical shampoos may seem to be enhancing the structure of hair throughout its length, but they can actually harm the roots.²⁷

Sensitive people may experience significant irritation from the artificial ingredients used in synthetic shampoos. · It causes nervous system damage and even cancer. · Synthetic shampoo active components can cause headaches, nausea, dizziness, and even vomiting.²⁸

8. CONCLUSION:

Hair is a key aspect of personal identity, and while cosmetic treatments can modify its appearance, they often come with risks. Ongoing research into hair biology and improved formulations aims to develop safer products that minimize damage while allowing for desirable aesthetic changes.

9. REFERENCES:

1. Gite Shital S., Jadhav Aishwarya J., Zalte Amar G., Saudagar Ravindra B. A Review on Oils used in Herbal Cosmetics. Res. J. Topical and Cosmetic Sci. 2013; 4(1): 61-64.

2. Pratibha Gavarkar, Rahul Adnaik, Dhanashree Chavan, Ashwini Bagkar, Rupali Bandgar. Physicochemical Investigation of Some Marketed Herbal Hair Oil. Research J. Topical and Cosmetic Sci. 2016; 7(2): 70-72. doi: 10.5958/2321-5844.2016.00011.X

3. Nanda Badhe, Lina Shirode, Shivam Lale. Formulation and Evaluation of Herbal Hair Tonic. Research J. Topical and Cosmetic Sci. 2015; 6(2): 86-90. doi: 10.5958/2321-5844.2015.00012.6

4. Human Hair Follicle: An Update on Biology and Perspectives in Hair Growth Disorders Treatment By Ines Brajac Marija. Container: Hair : Therapy and Transplantation. 2014; 4(1) DOI: 10.4172/2167-0951.1000115

5. Akshay Katkale, Rohini Jadhav, Sneha Sonawane. Formulation and Evaluation of Polyherbal Antidandruff Shampoo. Research Journal of Topical and Cosmetic Sciences. 2024; 15(2): 63-9. doi: 10.52711/2321-5844.2024.00011 \

6. Upeksha Rajapaksha, Nuwanthi P Katuwavila. Medical Remedies for Alopecia. Research Journal of Topical and Cosmetic Sciences. 2024; 15(2): 107-6. doi: 10.52711/2321-5844.2024.00018

7. Blume-Peytavi U, Blumeyer A, Tosti A, et al. S1 guideline for diagnostic evaluation in androgenetic alopecia in men, women and adolescents. Br J Dermatol. 2011; 164: 5–15

8. Heilmann S, Brockschmidt FF, Hillmer AM, et al. Evidence for a polygenic contribution to androgenetic alopecia. Br J Dermatol. 2013; 169: 927–30.

9. The Finasteride Male Pattern Hair Loss Study Group: Long-term (5-year) multinational experience with finasteride 1 mg in the treatment of men with androgenetic alopecia. Eur J Dermatol. 2002; 12: 38–49.

10. Whiting DA. Chronic telogen effluvium: increased scalp hair shedding in middle-aged women. J Am Acad Dermatol. 1996; 35: 899–906.

11. Kantor J, Kessler LJ, Brooks DG, Cotsarelis G. Decreased serum ferritin is associated with alopecia in women. J Invest Dermatol. 2003; 121: 985–8.

12. Blumeyer A, Tosti A, Messenger A, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men. J Dtsch Dermatol Ges. 2011; 9(Suppl 6): 1–57.

13. Suchonwanit P, Thammarucha S, Leerunyakul K. Minoxidil and its use in hair disorders: a review. Drug Des Devel Ther. 2019; 13: 2777. doi:10.2147/DDDT.S214907

14. Lucky AW, Piacquadio DJ, Ditre CM, et al. A randomized, placebocontrolled trial of 5% and 2% topical minoxidil solutions in the treatment of female pattern hair loss. J Am Acad Dermatol. 2004; 50: 541–53.

15. Van Zuuren EJ, Fedorowicz Z, Carter B. Evidence-based treatments for female pattern hair loss: a summary of a Cochrane systematic review. Br J Dermatol. 2012; 167: 995–1010.

16. Olsen EA, Dunlap FE, Funicella T, et al. A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. J Am Acad Dermatol. 2002; 47: 377–85.