Placebo: A pill, topical cream, or injection made to appear exactly like a test medication, but without any of its active ingredients.
Polysorbate 80: An emulsifying agent that has been marketed extensively by "private" companies as a hair growth promoting agent.
Postauricular Flap: Surgical procedure that takes hair-bearing scalp from the area behind the ear and rotates it 90 degrees to the front, forming a hairline.
Posterior Scalp: Back of the head.
Preauricular Flap: Surgical procedure that takes hair-bearing scalp from the temple area and rotates it about 90 degrees to the front, forming a hairline.
Progesterone: Female sex hormone that induces secretory changes in the lining of the uterus essential for successful implantation of a fertilized egg. Synthetic compounds with progesterone-like activity have been developed that, often along with estrogen, are used in oral contraceptives.
Propecia: The brand name for 1mg dose of finasteride, approved for the prevention and treatment of male pattern baldness.
Prosthetic: An artificial replacement.
Punch Graft: A group of ten to twenty hairs in a circular graft.
Recipient Site: Bald area where hair grafts are transplanted.
Rejection: Tissue not accepted by the body and which, therefore, dies.
Retin-A: A brand name for a prescription acne medication. Has in some cases shown to be effective against hair loss, particularly when combined with minoxidil. It can cause extreme scalp irritation that can make hair loss worse.
Retroauricular Area: Area behind the ear.
Rogaine: The brand name for minoxidil topical hair growth solution, available over the counter in 2% solution and in a 5% extra strength solution.
Rotational Flap: A surgical procedure that lifts a three-sided area of hair-bearing scalp and pivots it 90 to 180 degrees into the balding area.
Scalp Reduction: Surgical procedure in which an ellipse of bald scalp is removed from a small midline bald spot and the hair-bearing scalp between the ears is pulled together and sutured closed. This reduces the bald area.
Scarring Alopecia: Patchy hair loss with obvious sign of scalp inflammation.
Scleroderma: A disease of the skin and connective tissue that can cause hair loss over the affected areas.