Body hair transplant is taking out the follicles from the various donor areas of the body and not from the scalp itself. There are various differences between scalp donor & body hair donor and includes the orientation of follicular units, the skin type & laxity, the depth of hair follicle below the skin and most importantly thickness and curl of hair.
Body hair transplant is recommended when there is not sufficient scalp donor hair follicle to cover all of the recipient area. The compatibility of scalp and body hair as far as color and curl is concerned, is very important. If for example, the body hair of a specific patient is curly and his scalp hair is straight, then body hair transplantation on this patient will be difficult. Body hair usually grows to about 5cm, so the potential body hair transplant patient, must accept that he will cut his hair to the maximum of that length.
These patients must know their limitations and must be carefully selected.