Introduction
Hair is present on every part of the skin, protecting it from direct exposure to external factors. Hair morphology is different in each part of the human body, but the hairs on the scalp are considered to be the essential part of esthetics. The hairs are grown from the hair follicle at birth; they are small with age. These follicles grow and form a sebaceous gland that secretes sebum, natural oil that nourishes hair, and the hair on the scalp is called terminal hair, And when the follicle size decreases, the hairs start to shed, causing hair thinning.
What Is the Composition of Human Hair?
The single hair strand is composed of a sulfur-rich protein structure, lipids, minerals, water, melanin, and vitamins; it is a dead structure without living cells. In a cross-sectional view, hair is divided into three parts: cuticle, cortex, and medulla. The cuticle is made of keratin and multiple layers of flat cells directed towards the shaft; the cuticle is made of a-layer, a b-layer made of protein, and f-layer made of fiber; this layer is water-resistant and provides texture and luster to hair.
The cuticle can be damaged due to external factors like climate change and chemical and heat appliances which can make hair porous and lose its functional properties. The cortex comprises keratin consisting of amino acid residue and melanin granules; this layer provides strength and elasticity to the hair and can be damaged due to oxidative chemical changes leading to easy breakage.
The medulla is a soft protein layer seen in thicker and white hair. The hair thickness is classified into three, fine with less than 60 microns, medium with 60-80microns, and thick with 80-150 microns. The shape of hair and the cortex determines the susceptibility to damage. The greater the diameter of the cortex, the greater the strength of the hair, and this factor increases the longevity of the hair.
What Are the Causes of Hair Damage?
The damage to hair due to internal or external factors is called weathering. Modern research techniques help find the cause of the breakdown of hair at the nano-level. If it is due to the breakdown of chemical bonds or loss of elasticity or strength, the difference in single fiber leads to loss of shine and the changes that occur in the diameter of the hair.
As per the studies, the weathering can be natural or accelerated; natural weathering occurs due to physical damage to hair that happens while hair grooming, and accelerated weathering occurs due to excessive physical and chemical use on hair that leads to damage to cuticle and breakdown of hair protein, this can also lead to the breakdown of hair or split ends of hair.
The hair can be damaged due to excessive exposure to sunlight, the use of hair drying and grooming appliance, and harsh chemicals and metals used to straighten and curl hair; this can also lead to the breakdown of hair or split ends of hair.
The hair can be damaged due to excessive exposure to sunlight, use of hair drying and grooming appliances, and harsh chemicals and metals used to straighten and curl hair. In shampoo and other hair cosmetic products, this can break the cuticle layers and make hair look dull, frizzy, and thin.
What Is the New Research Found on Hair Regrowth?
The hair follicle is formed in the embryo with molecular signals called the hedgehog signal pathway, which is present in the body since birth and gradually shed off after birth. These signals are automatically shut down to prevent the crosslinking of messages.
Recent studies have shown that activation of the hedgehog signal pathway help in the growth of new hair follicles when keratinocytes and fibroblasts are activated; the study was carried out on mice and showed positive results, but the inappropriate activation of hedgehog can lead to the growth of tumors on the skin, but with the treatment of hedgehog inhibitor Vismodegib the growth of tumor was inhibited and new hair follicle was intact. However, the research still needs to go through several trials for effective results to show in humans.
Recent studies have found QR 678 scalp injection helpful in the regrowth of hair follicles; this treatment is considered an advanced non-surgical treatment better than stem cell treatment and plasma-rich protein treatment used for hair regrowth; 80% of hair regrowth was found in 90% of people who were injected in the duration of 6 months, this treatment is approved by Food Drug and Administration.
A scientist has found that in acute cases of hair loss, the immune cells attack the skin, which causes hair fall to stop; they use glucocorticoid to inhibit the immune reaction affecting the skin and leading to hair loss. In addition, the use of glucocorticoid helped activate regulatory T-cells, which produce TGF- beta 3, which is helpful in the growth of new hair follicle stem cells.
For effective hair growth, the hair cycling stages are essential to increase the hair growing phase and delay the hair losing or shedding phase; research is done to find a medicine that can help restore the hair and maintain the texture and volume, and hair density.
Therapy like topical Finasteride and Minoxidil have shown to be effective in a few people for hair growth; Finasteride prevents the conversion of testosterone to dihydrotestosterone which is the leading cause of hair loss by inhibiting 5 alpha reductase type 2 enzyme, while Minoxidil helps in increasing the hair growth phase and shortening the hair loss phase by producing enzyme 2-4-di-amino-6-piperidine pyrimidine-3-oxide, it also helps in enlarging the hair follicle size. However, this medicine is to be used regularly to maintain the results; the prolonged use of these drugs has many side effects; Finasteride has been shown to have sexual dysfunction in both men and women, and minoxidil is shown to have problems related to hypertension, headache, water retention.
Conclusion
Hair plays an essential role in esthetics as they affect the beauty of a person, they help in boosting the self-confidence of a person, and losing hair at an early age can be painful and affect self-esteem; the recent advancement in hair regrowth is promising but are still under trial, if this trial is successful then the problem of hair loss will be solved. Before opting for any treatment related to hair, it is advised to take the opinion of a healthcare provider with good experience and have shown effective results with no complications.