The roots of mod­ern day were cul­ti­vated in Japan in the late 1930s. In 1939, Japan­ese der­ma­tol­o­gist Dr. Okuda detailed his ground­break­ing work in sur­gi­cal hair restora­tion for burn vic­tims. He described using a punch tech­nique to extract round sec­tions of hair-bearing skin, which were then implanted into slightly smaller round holes made in the scarred or burned areas of the scalps of his patients. After the skin grafts healed, they con­tin­ued to pro­duce hair in the pre­vi­ously bald areas of scalp. In 1943 another Japan­ese der­ma­tol­o­gist refined Okuda’s tech­nique by using sig­nif­i­cantly smaller grafts of one to three hairs to replace lost pubic hair in his female patients.

In 1952, Dr. Nor­man Oren­tre­ich, a New York der­ma­tol­o­gist, per­formed the first known hair trans­plant in the U.S. on a man suf­fer­ing from male pat­tern bald­ing. Oren­tre­ich essen­tially rein­vented modern-day hair transplantation.

Seven years later, after much crit­i­cism, Oren­tre­ich pub­lished his find­ings and set forth his the­ory of “donor dom­i­nance” in the Annals of the New York Acad­emy of Sci­ences. His work demon­strated that the hair from the back and the sides of a man’s scalp was for the most part resis­tant to the bald­ing process. How­ever, his tech­nique mir­rored the less aes­thet­i­cally “punch graft” process of Okuda instead of the more nat­ural, smaller graft­ing tech­nique of Tamura.

It wasn’t until the mid 1990s that sur­gi­cal hair restora­tion pro­duced natural-looking results. Newer tech­niques, such as fol­lic­u­lar unit micro graft­ing, fol­lic­u­lar unit trans­plan­ta­tion, and fol­lic­u­lar unit extrac­tion, have made hair trans­plan­ta­tion a vir­tu­ally unde­tectable, viable option for many.

Hair Fol­li­cles

Hair has two dis­tinct struc­tures — first, the fol­li­cle itself, which resides in the skin, and sec­ond, the shaft, which is what is vis­i­ble above the scalp.

Two sheaths, an inner and outer sheath, sur­round the fol­li­cle. These struc­tures pro­tect and form the grow­ing hair shaft. The inner sheath fol­lows the hair shaft and ends below the open­ing of a seba­ceous (oil) gland, and some­times an apoc­rine (scent) gland. The outer sheath con­tin­ues all the way up to the gland. A mus­cle called an erec­tor pili mus­cle attaches below the gland to a fibrous layer around the outer sheath. When this mus­cle con­tracts, it causes the hair to stand up which also causes the seba­ceous gland to secrete oil.

Hair Shafts

The hair shaft is made of a hard pro­tein called ker­atin and is made in three lay­ers. This pro­tein is actu­ally dead, so the hair that you see is not a liv­ing struc­ture. The inner layer is the medulla. The sec­ond layer is the cor­tex and the outer layer is the cuti­cle. The cor­tex makes up the major­ity of the hair shaft. The cuti­cle is a tightly formed struc­ture made of shingle-like over­lap­ping scales. It is both the cor­tex and the medulla that holds the hair’s pig­ment, giv­ing it its color.

Hair Growth Cycle

Hair on the scalp grows about .3 to .4 mm/day or about 6 inches per year. Unlike other mam­mals, human hair growth and shed­ding is ran­dom and not sea­sonal or cycli­cal. At any given time, a ran­dom num­ber of hairs will be in one of three stages of growth and shed­ding: ana­gen, cata­gen, and telogen.