Appropriate preservation of cells & tissue is a critical factor in hair transplantation procedures. When the follicular units are harvested from the donor area, this tissue experiences multiple forms of stress related to the procedure. This can be especially true in automated operations where the grafts are dumped into a holding vessel by a suction. The gentler the live hairs & roots are handled the better the survival rate. Free radicals generated by normal metabolism are thought to be slowed by thermal cooling, and grafts should be refrigerated upon removal and before being placed into the recipient area for best results.