Follicular unit transplantation (FUT) is a hair restoration technique, also known as the strip procedure, where a patient's hair is transplanted in naturally occurring groups of 1 to 4 hairs, called follicular units. Follicular units also contain sebaceous (oil) glands, nerves, a small muscle, and occasional fine vellus hairs. In follicular unit transplantation, these small units allow the surgeon to safely transplant thousands of grafts in a single session, which maximizes the cosmetic impact of the procedure. FUT is considered an advance over older hair transplantation procedures that used larger grafts and often produced a pluggy, unnatural look. In a properly-performed follicular unit transplant, the results will mimic the way hair grows in nature and will be undetectable as a hair transplant. In recent history, FUT had been the most common procedure for hair restoration. As of 2017, the newer follicular unit extraction (FUE) procedure has become the most common procedure. Key concepts Follicular unit transplantation uses follicular units to accomplish a number of objectives critical to the hair restoration process: Maximizing hair transplant growth Since the follicular unit is a distinct anatomic and physiologic entity, preserving it intact during the graft dissection is felt to maximize growth. In FUT, after hair is removed from the back of the scalp in a single strip, stereo-microscopic dissection allows the individual follicular units to be removed from this strip without being damaged. In the older mini-micrografting techniques, hair was harvested in multiple strips with the follicular units in each strip edge showing damage from the harvesting blades. The strips were then cut into smaller pieces, a process that would break up follicular units and risk additional damage to the follicles. Ensuring the naturalness of hair transplant Follicular Unit Transplantation enables the hair transplant to look natural both at the individual follicular unit level and in regards to the overall graft distribution. Since scalp hair normally grows in follicular units of 1 to 4 hairs, the exclusive use of these naturally-occurring units in FUT ensures that each graft will be identical to the surrounding follicular units. Thus, when the transplanted follicular units grow hair after a transplant, the overall results of the transplant will appear natural. Additionally, by using individual follicular units, rather than larger grafts, the surgeon has a greater total number of grafts with which to work. This allows the surgeon to distribute the grafts more evenly over the scalp for