Our hair is part of what we call the integumentary system of the human body, which also includes the skin and nails. Hair is, in fact, a type of modified skin. It is made up of keratin, a form of protein, and is produced in tunnel-like structures in the skin called follicles. Inside the hair follicle is the hair bulb that is comprised of cells that deposit keratin and melanin, which is responsible for giving your hair its color. The hair that breaks through your skin from the follicle is the hair shaft. The shaft is basically composed of dead cells comprised of keratin fibres. In fact, the totality of hair on our head is a huge lump of dead cells, which explains why we don't experience any pain when we go for a haircut.
“We don’t know why, but we have universally established that the cells back there are immune to the attack,” Buckler said. That’s why doctors have worked at relocating follicles from the back of the head to the front to attempt to cure baldness. “That’s proven. If you relocate those cells, they’ll remain immune. “But that is a messy, bloody surgical procedure.”

A popular skin care drug—which is intended to target eczema—was just found to have an unusual side effect: hair growth. According to an article on Newsweek, the FDA-approved drug dupilumab was given to a 13-year-old alopecia sufferer to treat her eczema. The patient, who hadn’t grown hair on her scalp since she was two, suddenly grew a significant amount of hair on her head after continual use of the drug, a study in the journal JAMA Dermatology reports.
Another shampoo which is part of a “system” that includes conditioner and serum. And it’s yet another shampoo which has worked well on its own for many people. The HairGenesis shampoo (and the other products) contains a proprietary formula that is patent-pending, and the company says that the goal of the shampoo is to prepare hair for “maximum growth potential.” It also uses a lot of impressive sounding phrases to describe what the HairGenesis shampoo does.

Aside from medication and lasers, some opt for hair transplants — a procedure where hairs are removed from another part of your body and then transplanted to the thinning or balding areas. Does it work? In a word, yes. Research suggests that most hair transplant recipients report are "very satisfied" with their results. While successful, transplants are also far more expensive than medications, foams, or lasers with costs averaging anywhere from $4,000 or $15,000.
McElwee is an associate professor in the Department of Dermatology and Skin Health at the University of British Columbia (UBC) in British Columbia, Canada and director of the Hair Research Laboratory in the Vancouver Coastal Health Research Institute (VCHI) at Vancouver General Hospital (VGH). A hair research scientist, McElwee is one of only a small group of research scientists worldwide who studies hair biology and associated diseases. 

Dupilumab is FDA approved for treating eczema aka atopic dermatitis and sold under the brand name Dupixent.  As the story goes, a patient with alopecia totalis (a form of areata which leaves a person’s head completely bald) was being treated for eczema by the drug Dupixent. After 6 weeks the patient first began to notice progress in terms of hair growth and at 7 months she had noticeable pigmented hair growth on her scalp. Notably, the patient stopped taking the dupilumab for a period of time and noticed her growth subsided; when she began taking the drug again the hair improved once more. This provides another useful therapy option for patients seeking treatment for AA. One would imagine a topical version would be worthwhile to investigate.
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